Mercedes-Benz W202 manual gearbox faults
W202 manual: the gear jumps out, for example third. What causes it?
The most common cause is a missing or worn rubber bushing on the gear shift rod or the gear lever. Replace the rubber bushings and check the centring of the shift gate. If they are fine, the cause can be wear of the synchroniser and the engagement sleeve.
The gear won't engage or reverse won't engage. What do I check?
See whether the shift rod has come loose from the gearbox end. The rod's locking screws can loosen, and they can be seen from under the car with a long Torx 27 key. Reverse and fifth gear are operated with the same lever, so a loose rod prevents reverse.
The gears engage randomly or first gear won't go in without force. What could be the cause?
First it is worth adjusting the gear selector rods and checking that the clutch releases properly. A leaking input shaft seal can drain the gearbox oil, after which the gears start to stick. In that case the bearings and seals are renewed. The first gear synchroniser can also be worn.
What can cause a rumbling and grinding noise from the manual gearbox area?
The noise does not always come from the gearbox. The propshaft support bearing can growl when the throttle is off. Find out whether the fault is in the gearbox by turning the propshaft with the gear and the handbrake engaged: if it does not turn, the fault is in the gearbox. Also check the oil quantity.