GB2553829B

GB2553829B - Thermal isolation of transmission components

Info

Publication number: GB2553829B
Application number: GB1615803.2A
Authority: GB
Inventors: Kirby Mark
Original assignee: Jaguar Land Rover Ltd
Current assignee: Jaguar Land Rover Ltd
Priority date: 2016-09-16
Filing date: 2016-09-16
Publication date: 2019-10-30
Anticipated expiration: 2036-09-16
Also published as: GB2553829A; GB201615803D0

Description

THERMAL ISOLATION OF TRANSMISSION COMPONENTS

TECHNICAL FIELD

The present disclosure relates to a vehicle transmission assembly, and particularly, but not exclusively, to means for insulating parts thereof. Another aspect of the invention relates to a vehicle comprising a vehicle transmission assembly.

BACKGROUND

In an automotive vehicle, there are various components which exhibit peak performance when operated within a given ideal temperature range. An important example of this is in the powertrain of the vehicle, which includes the engine and the transmission, and in which a non-optimal temperature can lead to reduced vehicle performance. In particular, continuous elevated transmission temperature may cause excessive wear of components and ultimately may shorten the operational lifetime of the transmission. Conversely, low temperatures are detrimental to transmission performance and may greatly increase wear. One consequence of this is a reduction in the efficiency of the powertrain of the vehicle while the system reaches its operating temperature. This may affect the system at any time during its operation, but will be especially pronounced when first running the vehicle from cold when there is little or no heat retained in the powertrain from previous operation.

It is, therefore, clearly advantageous to be able to control the temperature of the transmission within a peak operating window and to ensure that the transmission reaches its ideal operating temperature as rapidly as possible after start-up. If this can be achieved, the enhanced performance of the transmission can translate into improved vehicle performance and fuel economy.

It is one object of the invention to provide a vehicle transmission assembly which addresses at least one of the problems described above.

SUMMARY OF THE INVENTION

According to an aspect of the invention, there is provided a vehicle transmission assembly comprising a transmission housing having an interior surface defining at least one oil bearing chamber, and at least one insulating member provided on at least a portion of the interior surface of the transmission housing. The at least one insulating member insulates the transmission housing from oil within the at least one oil bearing chamber. The at least one insulating member is a plastic moulding. A benefit of the invention is that the at least one insulating member provides thermal insulation between transmission oil contained within the at least one oil bearing chamber and the transmission housing. This reduces heat transfer between the transmission oil and the transmission housing, enabling the transmission oil to reach its optimum temperature more rapidly after vehicle start-up. Thus, transmission components housed within the oil bearing chambers may reach their peak operating temperatures more rapidly, leading to enhanced transmission performance. This, in turn, may lead to improved vehicle performance and better fuel economy of the vehicle.

Providing the at least one insulating member as a plastic moulding allows the insulating member to be formed as an independent, free-standing unit, before insertion in the transmission housing.

An exterior surface of the at least one insulating member may abut with at least a portion of the interior surface of the transmission housing. Alternatively, a gap may be provided between the at least one insulating member and at least a portion of the interior surface of the transmission housing.

The at least one oil bearing chamber may comprise a gear chamber and a sump chamber.

The at least one insulating member may comprise at least one drain aperture for allowing passage of transmission fluid from the gear chamber to the sump chamber.

The at least one insulating member may include an insulating sleeve provided in the gear chamber. The insulating sleeve may be positioned to substantially encircle components housed in the gear chamber. The insulating sleeve may be substantially cylindrical. The insulating sleeve may comprise an output shaft-receiving opening.

The insulating sleeve may comprise a plurality of ridges surrounding the output shaftreceiving opening. The plurality of ridges may be configured to mate with corresponding features on an interior surface of the gear chamber. This ensures a close fit of the insulating member with the transmission housing.

The insulating sleeve may have a substantially open end. This enables assembly of transmission components in the transmission housing after insertion of the insulating member.

The at least one insulating member may include a sump insert. The sump insert may be provided in the sump chamber. The sump insert may have a generally open boxlike structure.

According to an aspect of the invention, there is provided a method of assembling a vehicle transmission assembly. The method comprises providing a transmission housing having an interior surface defining a gear chamber, providing at least one insulating member on at least a portion of the interior surface defining the gear chamber, and installing transmission components in the gear chamber, such that the at least one insulating member at least partially surrounds the at least one transmission component. The at least one insulating member is a plastic moulding. The at least one transmission component may include a plurality of gear sets.

Providing the at least one insulating member on at least a portion of the interior surface defining the gear chamber may comprise inserting the at least one insulating member into the gear chamber. In this way, the at least one insulating member may be provided as a simple pre-formed, free-standing component which may be slotted into place before insertion of other transmission components.

Providing the at least one insulating member on at least a portion of the interior surface defining the gear chamber may comprise moulding the at least one insulating member on at least a portion of the interior surface defining the gear chamber.

In examples outside of the scope of the invention, providing the at least one insulating member on at least a portion of the interior surface defining the gear chamber may comprise depositing the at least one insulating member on at least a portion of the interior surface defining the gear chamber.

According to an aspect of the invention, there is provided a method of assembling a vehicle transmission assembly, the method comprising providing a transmission housing having an interior surface defining a sump chamber, providing at least one insulating member on at least a portion of the interior surface defining the sump chamber, installing at least one transmission component in the sump chamber, such that the at least one insulating member at least partially surrounds the at least one transmission component. The at least one insulating member is a plastic moulding. The at least one transmission component may comprise a transmission control apparatus.

As above, in this aspect of the invention providing the at least one insulating member on at least a portion of the interior surface defining the gear chamber may comprise inserting the at least one insulating member into the sump chamber. Providing the at least one insulating member on at least a portion of the interior surface defining the sump chamber may comprise moulding the at least one insulating member on at least a portion of the interior surface defining the sump chamber. In examples outside of the scope of the invention, providing the at least one insulating member on at least a portion of the interior surface defining the gear chamber may comprise depositing the at least one insulating member on at least a portion of the interior surface defining the sump chamber.

According to one aspect of the invention, there is provided a vehicle incorporating a vehicle transmission assembly according to the above aspects of the invention.

Within the scope of this application it is expressly intended that the various aspects, embodiments, examples and alternatives set out in the preceding paragraphs, in the claims and/or in the following description and drawings, and in particular the individual features thereof, may be taken independently or in any combination. That is, all embodiments and/or features of any embodiment can be combined in any way and/or combination, unless such features are incompatible. The applicant reserves the right to change any originally filed claim or file any new claim accordingly, including the right to amend any originally filed claim to depend from and/or incorporate any feature of any other claim although not originally claimed in that manner.

BRIEF DESCRIPTION OF THE DRAWINGS

One or more embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

Figure 1 is a cross section of an automatic transmission, suitable for use with the invention;

Figure 2 is a perspective view of a portion of a vehicle transmission assembly of the invention, comprising a transmission housing, a first insulating member and a second insulating member;

Figure 3 is a side view of the vehicle transmission assembly of Figure 2;

Figures 4a and 4b are perspective views of the first insulating member of Figure 2;

Figure 5 is an end view of the first insulating member of Figures 4a and 4b;

Figure 6 shows a lower portion of the first insulating member of Figures 4a and 4b;

Figures 7a and 7b are perspective views of the second insulating member of Figure 2;

Figure 8 shows an upper portion of the second insulating member of Figures 7a and 7b;

Figures 9a and 9b are side views of the second insulating member of Figures 7a and 7b;

Figures 10a and 10b are front end and rear end views, respectively, of the second insulating member of Figures 7a and 7b;

Figure 11 is a perspective view, from below, of the vehicle transmission assembly of Figure 2, showing the first and second insulating members positioned in the transmission housing ready for use;

Figure 12 is a perspective view of the vehicle transmission assembly in Figure 11 from an alternate angle, showing the first and second insulating members positioned in the transmission housing ready for use, with drain apertures of the first and second insulating members and the transmission housing aligned; and

Figure 13 shows the vehicle transmission assembly incorporated in a vehicle.

DETAILED DESCRIPTION

Figure 1 shows a schematic of an automatic transmission 10 for a vehicle 12, suitable for use with the present invention.

The transmission 10 forms a part of the powertrain of the vehicle, and is responsible for transferring power from the engine to the wheels. Referring to Figure 1, the transmission comprises gear sets 14, a torque converter 16, a hydraulic system 18, transmission control apparatus 19 and a transmission housing 22.

The gear sets 14 of the transmission 10 are provided to offer different gear ratios and are housed in a gear chamber 44 of the transmission housing 22.

The torque converter 16 is provided between the engine 17 (shown in Figure 13) and the transmission 10, and acts as a clutch to couple torque from the engine to the transmission 10. The torque converter 16 is housed in a bell housing 26 which may be bolted to the transmission housing 22 or alternatively may form an integral part of the transmission housing 22.

The hydraulic system 18 comprises transmission fluid (not shown) such as oil, a transmission pump 28 mounted at a front end 30 of the transmission housing 22 and driven off the torque converter 16, a plurality of oil transfer passages 32 provided in the transmission housing, and a transmission sump 34 located below the transmission housing 22. The transmission oil pump 28 pulls fluid from the transmission sump 34 via a filter and this oil is then sent under pressure to the transmission components as required by means of the oil transfer passages 32. In this way, the hydraulic system 18 provides general lubrication and cooling of transmission components, thus ensuring effective operation of the vehicle transmission 10 in use.

The transmission control apparatus 19 comprises a transmission control unit 20 that is mounted to a lower portion of the transmission housing 22 and is responsible for controlling components of the transmission 10. The transmission control unit 20 may receive a variety of inputs from sources such as vehicle sensors (not shown), and use these to determine when the transmission should change gears. The transmission control unit 20 may then generate and send command signals to components of the transmission to implement a gear change. The inputs received by the transmission control unit 20 may include, for example, inputs from sensors on the vehicle such as vehicle speed and wheel speed sensors, and inputs from an engine control unit (not shown). In the art, transmission control units positioned internal to gearbox housings may sometimes be referred to as ‘mechatronics’ or ‘mechatronic units’. It should be noted that, although the transmission control apparatus 19 has been described in terms of an electronic control module (i.e. the transmission control unit 20), the transmission control apparatus 19 may comprise any component that is used in the control of the transmission such as, for example, a control valve assembly (not shown).

Referring now also to Figure 2, the transmission housing 22 comprises a front portion 36, a rear portion 38, an upper portion 40, a lower portion 42 and an interior surface 43. The transmission housing 22 further comprises two oil bearing chambers 45; a gear chamber 44 and a sump chamber 46.

The gear chamber 44, which houses transmission components such as the gear sets 14 in use, is a generally cylindrical-shaped cavity that is formed by a gear chamber casing 48 of the transmission housing 22. The gear chamber casing 48 is provided with an interior surface 50 that defines the gear chamber 44, and comprises a front end 52 and a rear end 54. The front end 52 of the gear chamber casing 48 defines a generally circular shaped opening 56 at the front portion 36 of the transmission housing 22, adjacent the torque converter housing 26. The rear end 54 of the gear chamber casing 48 comprises a rear wall 58 having an output shaft-receiving opening 60 through which an output shaft 61 of the transmission extends in use. The rear end 54 of the gear chamber casing 48 is located at the rear portion 38 of the transmission housing 22. Note that the shaft 61 is shown in Figure 1, but is not shown in Figures 2 and 3.

The sump chamber 46 is provided at the lower portion 42 of the transmission housing 22 and comprises a generally rectangular-shaped cavity formed within an upper sump chamber casing 62 and a lower sump chamber casing 64. From comparing Figures 1, 2 and 3, it will be noted that the lower sump chamber casing 64 is not present in Figures 2 and 3. Thus, the lower sump chamber component 64 is a component that is separable from the rest of the transmission housing 20.

The upper sump chamber casing 62 comprises a generally rectangular shaped (in plan view) upper wall 66 and four side walls 68 depending therefrom, forming an open boxlike structure. The upper wall 66 of the upper casing 62 comprises attachment points for attaching componentry to the upper wall 66 of the upper casing 62, and oil transfer lines and passages 32 to enable routing of transmission fluid from the sump chamber 46. For example, as best seen in Figure 2, the transmission housing 22 comprises a mounting portion 72 for attaching the transmission control unit 20 to the transmission housing 22.

The upper sump chamber casing 62 further comprises a circumferential flange 74 that protrudes perpendicularly from an end of each of the side walls 68 of the upper casing 62, and extends about the entire circumference of the upper casing 62. The flange 74 is provided with a plurality of through-holes 76 about its circumference which form attachment points for attaching the lower sump casing 64 to the upper sump casing 62.

The lower sump chamber casing 64 is formed by the transmission sump 34, which is provided as a tray or pan, and is usually formed from a metal such as steel, but may also be a suitable plastics material. The transmission sump 34 also comprises a circumferential flange (not shown) having a plurality of through-holes (not shown), and these form attachment points for attaching the transmission sump 34 to the upper sump chamber casing 62.

To form the sump chamber 46, the lower sump chamber casing 64 is mounted to the upper sump chamber casing 62 by means of bolts (not shown) provided at the attachment points of the corresponding upper and lower sump chamber casing flanges. When the sump chamber casings 62, 64 are assembled in this way, interior surfaces 78 and 80 of the upper and lower casings respectively, together define an interior surface 82 of the sump chamber casing, which in turn defines the sump chamber 46.

Referring now also to Figure 3, a vehicle transmission assembly 84 in accordance with an embodiment of the invention is shown. The vehicle transmission assembly 84 comprises the transmission housing 22 and at least one insulating member 86. In this particular embodiment of the invention, the vehicle transmission assembly 84 is provided with two insulating members 86 for insulating the transmission housing 22 from oil within the gear chamber 44 and the sump chamber 46. However, in other embodiments of the invention there may be provided only one insulating member 86, or alternatively there may be provided more than two insulating members 86.

The two insulating members 86 of the vehicle transmission assembly 84 are formed by a first insulating member 88 and a second insulating member 90.

The first insulating member 88 is arranged in the gear chamber 44 of the transmission housing 22, and is provided on the interior surface 50 of the gear chamber casing 48. Thus, the first insulating member 88 is positioned between the transmission oil contained in the gear chamber 44 and the transmission housing 22 in use. The second insulating member 90 is provided on the interior surface 78 of the upper sump chamber casing 62 such that it sits between a portion of the transmission housing 22, and transmission oil contained in the sump chamber 46, in use.

In this way, the insulating members 88, 90 of the invention provide thermal insulation between transmission oil contained within oil bearing chambers 44, 46 of the vehicle transmission assembly 84, and the transmission housing 22. This reduces heat transfer between the transmission oil and the transmission housing 22, thus enabling the transmission oil to reach its optimum temperature more rapidly after vehicle startup, such that the transmission components housed within the oil bearing chambers 44, 46 are also able to reach their peak operating temperatures more rapidly.

The first insulating member 88 will now be described with reference to Figures 4 to 6, which show different views of the first insulating member 88 in isolation from the transmission housing 22.

The first insulating member 88 is an insulating sleeve formed as a plastic moulding. In principle, a different suitable insulating material could be used to make the insulating member, so long as the material can hold its shape and is robust enough to withstand the harsh environment in which it will be located. For example, the first insulating member 88 may be formed of polyurethane foam, a polyamide such as nylon, or rubber. In embodiments outside of the scope of the invention, rather than being provided in the form of a moulding, the first insulating member 88 may be provided as an insulating coating deposited on the internal surface of the transmission casing. The insulating coating may be deposited by spraying and may be formed of a suitable insulating material such as Zylon RTM. It is currently preferred, however, that the sleeve is a free standing component, rather than a deposited component.

Referring now to Figures 4a and 4b, the insulating sleeve 88 has a generally cylindrical shape and is dimensioned such that when the sleeve is positioned inside the gear chamber casing 48, the sleeve abuts the interior surface 50 of the gear chamber casing 48.

The insulating sleeve 88 comprises a front end 92, a rear end 94, an upper portion 96 and a lower portion 98. The sleeve 88 further comprises an interior sleeve surface 100 that faces the gear chamber 44 in use, and an exterior surface 102 that abuts the interior surface 50 of the gear chamber casing 48 in use.

The front end 92 of the insulating sleeve 88 provides a generally circular shaped opening 104 that corresponds with the open front end 52 of the gear chamber casing 48 when the vehicle transmission assembly 84 is assembled for use. The rear end 94 of the sleeve 88 comprises a rear wall 106 having a circular output shaft-receiving opening 108. When arranged for use, the output shaft-receiving opening 108 of the sleeve 88 aligns with the output shaft-receiving opening 60 of the transmission housing 22 to allow the output shaft 61 to extend through, in use.

The rear end 94 of the sleeve 88 further comprises a key formation 110 in the form of a plurality of ridges surrounding the output shaft-receiving opening 108. With particular reference to Figure 5, the ridges 110 of the sleeve 88 extend about the entire circumference of the output shaft-receiving opening 108, and extend radially outwards from an edge 111 of the output shaft-receiving opening 108. In use, these ridges 110 abut with corresponding grooves (not shown) on the interior surface 50 of the gear chamber casing 46 in the manner of a key and ensure a close fit between the sleeve 88 and the transmission housing 22 in the region surrounding the output shaftreceiving openings 60, 108.

Referring now to Figure 6, the insulating sleeve 88 further comprises a plurality of generally rectangular shaped apertures 112. These apertures 112 are generally provided on the lower portion 98 of the insulating sleeve 88 and provide access to mounting points on the inside of the gear chamber casing 48, as well as providing drainage routes for transmission fluid from the gear chamber 44 to the sump 34 via the sump chamber 46.

In more detail, and with reference to Figure 6, the apertures comprise a plurality of drain apertures 114, a park lock aperture 116, and a transmission pump aperture 118. The drain apertures 114 of the sleeve 88 are positioned such that, when the sleeve 88 is positioned in the gear chamber casing 48 for use, the drain apertures 114 of the sleeve align with drain apertures in the gear casing 115 and drain apertures 116 in the second insulating member 90, as best seen in Figure 12. In this way, transmission fluid is able to drain from the gear chamber 44 to the sump chamber 46, thereby allowing the transmission fluid to be cooled and recirculated by the hydraulic system 18 during operation. The park lock aperture 116 is located to the rear end 94 of the sleeve 88 and enables a park locking system of the vehicle, which locks up the transmission and prevents it from rotating, to be fitted to the transmission housing 22. The transmission pump aperture 118 is provided at the front end 92 of the insulating sleeve 88 and aligns with corresponding openings in the transmission housing 22 and the second insulating member 90 to allow components associated with the transmission pump 28 to extend through, in use.

The second insulating member 90 will now be described with reference to Figures 7 to 10, which show different views of the second insulating member 90 in isolation from the transmission housing.

Referring to Figures 7a and 7b, the second insulating member 90 is a sump chamber insert formed as a plastic moulding and having a generally rectangular shape, and will hereinafter be referred to as the ‘sump insert’. The sump insert 90 is dimensioned to correspond with the shape of the interior surface 78 of the upper sump chamber casing 62. In embodiments outside of the scope of the invention, the second insulating member 90 may be formed of an insulating coating which may be deposited on the interior surface 50 of the upper sump chamber casing 62. As with the first insulating member 88, the second insulating member 90 may be formed of suitable insulating materials, including, but not limited to, polyurethane foam, nylon, or rubber.

The sump insert 90 has a generally rectangular-shaped body 120 comprising a generally rectangular-shaped main portion 122 and four side walls 124 extending therefrom. The body 120 of the sump insert comprises an interior surface 125 that faces the sump chamber in use, and an exterior surface 127 that abuts the interior surface of the upper sump chamber casing in use. The body 120 of the insert 90 is further provided with a plurality of apertures 126 of varying size and shape to provide access to mounting points of the sump chamber casing and to provide drainage routes for transmission fluid to pass from the gear chamber 44 to the sump chamber 46 in use.

In more detail, a generally L-shaped aperture 128 provides access to the attachment portion 72 for mounting the transmission control unit 20 and enables routing of transmission fluid to the components of the transmission by means of oil transfer passages moulded into the housing 22 of the transmission assembly 84. A plurality of drain apertures 115, which align with corresponding openings 114, 116 in the insulating sleeve 88 and transmission housing 22 respectively, provide a route for transmission fluid to drain from the gear chamber 44 to the sump chamber 46 in use. A transmission pump aperture 129 allows for extension of the transmission pump through the sump insert 90 in use.

As best illustrated in Figures 10a and 10b, the main portion 122 of the sump insert 90 has a generally C-shaped lateral profile that provides a close fit between the sump insert 90 and the interior surface 78 of the upper sump chamber casing 62, which is cylindrical.

The vehicle transmission assembly 84, comprising the transmission housing 22 and the first and second insulating members 88, 90 positioned for use, is best illustrated in Figures 2, 11 and 12.

The first and second insulating members 88, 90, both provided as plastic mouldings, may be formed separate of the transmission housing 22 and subsequently slotted into position before assembly of the remaining transmission components. In this way, the first and second insulating members 88, 90 are provided as pre-fabricated, selfstanding or self-supporting, units that are inserted into their respective oil bearing chambers 44, 46. Alternatively, the insulating members 88, 90 may be moulded directly into the transmission housing 22 prior to machining.

When the insulating members 88, 90 are positioned for use, the insulating sleeve 88 is positioned in the gear chamber 44 and the sump insert 90 is positioned in the sump chamber 46. The insulating sleeve 88 abuts with the interior surface 50 of the gear chamber casing 48 and the sump insert 90 abuts with the interior surface 78 of the upper sump chamber casing 62. The ridges 110 of the insulating sleeve 88 align with the corresponding grooves on the interior surface 50 of the gear chamber casing 46, and the apertures of the insulating sleeve align with the corresponding apertures of the transmission housing 22 and the sump insert 90.

In this particular embodiment of the invention, the sleeve 88 and the sump insert 90 abut with surfaces of the transmission housing when positioned for use. However, in other embodiments there may be provided a gap between the insulating members 88, 90 and the transmission housing 22 to provide additional insulation.

The first and second insulating members 88, 90 provide insulation between the transmission housing 22, and the gear chamber 44 and sump chamber 46, guarding against heat loss from oil housed within these chambers. This is advantageous as it enables transmission components to reach their optimum operating temperature more rapidly than they would without this insulation being present. This beneficially impacts the overall efficiency of the system, as the transmission operates with reduced efficiency for a shorter period of time during start-up. In this way, the invention increases vehicle performance and, in turn, has a positive impact on fuel economy.

Turning now to Figure 13, this shows the transmission assembly 84 implemented in a vehicle 12. Drive from the engine 17 is directed via the transmission 10 to a rear differential 130 of a rear drive axle 132 by the drive shaft 61 running longitudinally along the centre of the vehicle 12. The engine 17 is therefore configured to drive a set of rear wheels 134, and the vehicle in this embodiment is a rear wheel drive. However, it should be noted that the transmission assembly 84 of the invention could be used in any type of vehicle 12 having a transmission 10, for example the transmission assembly 84 could equally be used in a vehicle having all wheel drive.

It should also be noted that although the above description relates to use of the invention with an automatic transmission, the invention could equally be used with a manual transmission.

Claims

1. A vehicle transmission assembly comprising; a transmission housing having an interior surface defining at least one oil bearing chamber, and, at least one insulating member provided on at least a portion of the interior surface of the transmission housing, wherein the at least one insulating member insulates the transmission housing from oil within the at least one oil bearing chamber, and wherein the at least one insulating member is a plastic moulding.

2. A vehicle transmission assembly as claimed in claim 1, wherein an exterior surface of the at least one insulating member abuts with at least a portion of the interior surface of the transmission housing.

3. A vehicle transmission assembly as claimed in any one of the preceding claims, wherein the at least one oil bearing chamber comprises a gear chamber and a sump chamber.

4. A vehicle transmission assembly as claimed in claim 3, wherein the at least one insulating member comprises at least one drain aperture for allowing passage of transmission fluid from the gear chamber to the sump chamber.

5. A vehicle transmission assembly as claimed in claim 3 or claim 4, wherein the at least one insulating member includes an insulating sleeve provided in the gear chamber and positioned to substantially encircle components housed in the gear chamber.

6. A vehicle transmission assembly as claimed in claim 5, wherein the insulating sleeve is substantially cylindrical.

7. A vehicle transmission assembly as claimed in any one of claims 5 or 7, wherein the insulating sleeve comprises an output shaft-receiving opening.

8. A vehicle transmission assembly as claimed in claim 7, wherein the insulating sleeve comprises a plurality of ridges surrounding the output shaft-receiving opening, configured to mate with corresponding features on an interior surface of the gear chamber.

9. A vehicle transmission assembly as claimed in any one of claims 5 to 8, wherein the insulating sleeve has a substantially open end.

10. A vehicle transmission assembly as claimed in any one of claims 4 to 9, wherein the at least one insulating member includes a sump insert, and wherein the sump insert is provided in the sump chamber.

11. A vehicle transmission assembly as claimed in claim 10, wherein the sump insert has a generally open box-like structure.

12. A method of assembling a vehicle transmission assembly comprising; providing a transmission housing having an interior surface defining a gear chamber, providing at least one insulating member on at least a portion of the interior surface defining the gear chamber, wherein the at least one insulating member is a plastic moulding, installing transmission components in the gear chamber, such that the at least one insulating member at least partially surrounds the at least one transmission component.

13. A method of assembling a vehicle transmission assembly as claimed in claim 12, wherein the transmission components include a plurality of gear sets.

14. A method of assembling a vehicle transmission assembly as claimed in claim 12 or 13, wherein providing the at least one insulating member on at least a portion of the interior surface defining the gear chamber comprises inserting the at least one insulating member into the gear chamber.

15. A method of assembling a vehicle transmission assembly as claimed in claim 12 or 13, wherein providing the at least one insulating member on at least a portion of the interior surface defining the gear chamber comprises moulding the at least one insulating member on at least a portion of the interior surface defining the gear chamber.

16. A method of assembling a vehicle transmission assembly comprising; providing a transmission housing having an interior surface defining a sump chamber, providing at least one insulating member on at least a portion of the interior surface defining the sump chamber, wherein the at least one insulating member is a plastic moulding, installing at least one transmission component in the sump chamber, such that the at least one insulating member at least partially surrounds the at least one transmission component.

17. A method of assembling a vehicle transmission assembly as claimed in claim 16, wherein the at least one transmission component comprises a transmission control apparatus.

18. A method of assembling a vehicle transmission assembly as claimed in claim 16 or 17, wherein providing the at least one insulating member on at least a portion of the interior surface defining the gear chamber comprises inserting the at least one insulating member into the sump chamber.

19. A method of assembling a vehicle transmission assembly as claimed in claim 16 or 17, wherein providing the at least one insulating member on at least a portion of the interior surface defining the sump chamber comprises moulding the at least one insulating member on at least a portion of the interior surface defining the sump chamber.

20. A vehicle incorporating a vehicle transmission assembly as claimed in any one of claims 1 to 11.