Mercedes 190d Transmission sometimes won't shift into gear


#1

I recently acquired a 5 spd '84 Mercedes 190D (4 cyl diesel) with 160k miles with the intention of using it as a commuter and converting it to run on veggie oil. Since I’ve had it, it has occasionally been tough to shift into 1st gear when getting started. When this happens, the shifter does not push into 1st, but with a little gas or letting the car roll a bit, it will click into place. No other gears are a problem. But, twice recently, I’ve exited the highway after driving in 5th gear for 30+ minutes and then not been able to shift into any of the gears. I’ll put the clutch all the way to the floor, but when I try any of the gears, I get resistance from the shifter and feel a kind of rubbing - but not the typical screeching of gears not meshing that you would hear when you miss a gear with the clutch out. I can shift into reverse, but when I do this(with the clutch in) the car stalls. The last time this happened I turned the car of and then back on again and it shifted right into first like there was no problem. What could this be - clutch, clutch bearing, shift bearing, transmission fluid, transmission, or some kind of vaccuum thing?


#2

I think the clutch is not disengaging all the way. If it’s a hydraulic clutch, there may be a leak in the system. If it’s a cable-operated clutch it may need adjustment.

Is it easier to get in gear if you pump the clutch a few times?

Does it ever give you this problem when the engine is off?


#3

Assuming that this is a manual transmission, I agree with mcparadise that the clutch is not completely disengaging and it most likely is a problem in the hydraulic clutch. If the synchronizers are in good shape they will block the shift rather than allowing the clutch dog teeth to slip through to grind against the gear clutch teeth. It also could be a defective input shaft pilot bearing/bushing; a problem with the clutch disk; or a problem with the pressure plate.


#4

You car has a hydraulic clutch that shares a reservoir with the brakes, as I recall. Make sure the fluid level is OK. It may be a problem with the slave cylinder, causing the cluck not to fully disengage.


#5

Thanks all for the advice. I think you’re right that the clutch is not fully disengaging. I sometimes hear a metallic rattle when the car is idling, out of gear and the clutch is out, that goes away when I push the clutch in. Could this rattling be the input shaft pilot bearing?

As far as I know the shift problem only happens when the car is running.

My first thought, as mentioned below, is to check the hydraulic system and fluid level. If those aren’t the culprit, what is the next step?