My wifes diesel 190 makes a annoying groan from the gearbox/driveshaft/diff ? when travelling at low speeds in higher gears. The noise seems to come from the rear of the gearbox but could be travelling along the driveshaft from the diff. The noise goes away once the load is reduced i.e. changing down to a lower gear [ 5 speed manual] or increasing roadspeed . There is no noise at high speed or high engine revs and no noise on the overrun. I have replaced both flexi discs and the centre bearing feels ok offthe car . The vibration damper is worn but my dealer tells me this is only available with a complete drive shaft !, I am not convinced that the damper will cure the noise. I have replaced all the subframe mounts and rear suspension links/ bushes. Do you think it is worth replacing the motor and trans mounts ?. Replacing the ultra expensive driveshaft ?, rebuilding the gearbox, or replacing the diff?. I have not driven another manual 190 diesel but I cannot believe that this noise can be normal, I have tried synthetic oils and additives with no improvement the noise is so unBenz like , please offer your advice p-lease Thanks Linds U.K.

Here in the US you can get the BALANCER for the driveshaft & many times that is the problem. Or you can try removing the balancer to see if that is the problem. ON my racecar I removed it over 4 years ago & no problems even at 130mph. There are several DIFFERENT bolt circles on the flex-disc. ie; 80mm, 90mm, & 100mm. Let me know the size & I can look up the correct part number.
Is the center support in good shape.

__________________
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator

Thanks again M.B.DOC I will try to measure the bolt centres for the vib damper over the next few days, not the most accessable of parts on 190's. The centre suppourt seems OK but I'am not sure how flexible/ spongy the mount should be? the driveshaft UJ as a slight tightspot when moving in one plane, but I would think this was more likely to cause a vibration at higher road speeds than the noise at low speeds under load, what do you think?
Thank you for sharing your knowledge and experience it is much appreciated. Linds U.K.

My 300D 2.5 turbo has this same noise. Has anyone figured out what it is?