It is important that before fitting the replacement unit, the cause of the original gearbox failure is identified, and where appropriate, remedial action is taken. Failure to do so may result in similar problems with the replacement gearbox, which will not be covered by the gearbox warranty.
Before installation, always visually check that the replacement gearbox is compatible with the unit it is replacing. The gearbox supplied may be fitted with temporary transport items (locking pins, tools etc).
Always carefully read any information or instruction labels that may be supplied with the unit, or attached to the gearbox or packaging, as they may be specific to the gearbox supplied.
It is good practice that all ancillary parts should be checked and thoroughly cleaned prior to refitting to the exchange unit.
The gearbox is supplied without gearbox oil. It should be filled with oil that meets the vehicle manufacturer’s specifications, and should only be filled using the method and quantity of oil recommended by the vehicle manufacturer.
Filling the gearbox with oil until it runs out of the filler plug hole may result in the gearbox being either underfilled or overfilled with oil, both of which may lead to premature failure of the unit.
- On 4 X 4 vehicles the transfer box may also require filling as a separate unit.
- Some gearboxes are very slow to fill, and may take additional time to fill with the correct quantity of oil.
Gearbox Mountings and Linkages
Carefully check all engine and gearbox mountings for damage and wear and renew as necessary.
Inspect all gear change linkages and cables for damage and wear, and replace as necessary.
After installing the gearbox, the linkage and/or cables should be adjusted in accordance with the manufacturers recommended procedures / specifications.
Locating Dowels and Spigot Bearing
The locating dowels MUST be fitted to the gearbox before fitment. If the dowels cannot be removed from the old unit or have been misplaced, then new items must be purchased and fitted before the gearbox is installed. Spigot bearings or bushes (if fitted) should always be replaced when replacing the gearbox.
Flywheel and Clutch
When replacing the gearbox, it is good practice to replace the clutch assembly. Prior to installation, check that the driven plate can slide smoothly along the input shaft splines.
If the vehicle is fitted with a Dual Mass Flywheel (DMF), this must be checked for wear (radial and axial movement) as recommended by the vehicle manufacturer. Excessive wear in the DMF may lead to premature gearbox failure.
Driveshafts / Propshafts
Check propshaft universal joints and bearings for wear and replace as necessary. Excessive play in a bearing or joint can result in gearbox oil seal leakages, damaged gearbox bearings and premature gearbox failure.
Before installing driveshafts, check any joints or support bearings for wear. Also check the splines for wear, the condition of the locating clip / circlip and oil seal running area and replace as necessary.
Check wheel bearings for wear / excessive movement and replace as necessary.
On front wheel drive vehicles, check the lower suspension arms and bushes for wear, as any excessive movement may cause premature gearbox or driveshaft failure.
ALWAYS support the weight of the gearbox during removal and fitment. Failure to do so could cause clutch component damage, resulting in gear selection issues.
Do not use the bellhousing bolts to draw the gearbox on to the engine, as this can also lead to damage to the clutch components, gearbox casing and the input shaft and bearings.
After road testing the vehicle, check that all bolts are correctly tightened and that linkages and/or cables are correctly aligned. Inspect for oil leaks and re- check oil levels.