I have a 1989 190D with the 4 speed automatic transmission. Other than occasionally being a little rough with the 3-2 down-shift, the transmission shifts fine. The other day, as I was accelerating Up to speed on the interstate (65 MPH), everything was still going smoothly. However, once I got to 65 MPH and stopped accelerating, there was this constant clatter coming from the transmission. Some times it seemed that I could put a little pressure on the shifter and the noise would lessen.

I got off of the interstate at the next exit and headed back home on the back roads. Once again, the transmission shifted fine, but the clatter did come back once I got into 4th gear and was not accelerating.

The next day, I removed the cover from the shifter lever and went back-out to repeat the event. I drove for miles (never going more than 55 MPH) on back roads with no noises. I decided to hit the interstate again (same place, same acceleration) and the same thing happened but I still couldn't diagnose what exactly was causing the clattering.

Does this sound like an internal transmission problem?

If I do need to replace the transmission, which year/model will fit mine. I've heard that any 1986-1989 2.5 Diesel (including the 2.5 Turbo) will work. I also saw a thread in this forum where someone used the transmission from a gas 2.3 (year was not specified). I can certainly find gas 2.3 transmissions.

 

try look at the centre bearing carrier on the drive shaft first.

 

Well, it was the transmission. I did go ahead and replace the center bearing, and both of the flex disks. I got the transmission from Adsitco (Mercedes Benz Parts & Accessories - Adsit Company Inc.) as recommended by Potomac German Automotive. The transmission replacement was a job (especially from under the car in my driveway). After dropping the transmission mount, there was enough room to get to all of the 17mm tranmission to engine bolts. I had over 20 inches of 1/2 drive extensions (with wooble) and a 10 in breaker bar. I would guide the socket and extensions on to the head of the bolts (with my son's help). Once securely on, I would have him hold it there until I could get back and actually break it free.

For me, the hardest part was getting the transmission free from the engine and getting it back on. The engine wanted to tilt forward as the transmission weight was being removed (or added) and kept putting everything in a bind. I was also worried about dropping the torque converter. I finally got it off by shear force (a big yank on it). However, while putting the new one back in, I used my floor jack to keep the engine in one place and it slide together easily. Still, I would advise anyone to be careful with the torque converter. Mine never dropped but I constantly kept an eye on it. Also, lifting the transmission onto the jack (I just used my trusty floor jack and a piece of wood) while under the car is something (profanity is required to accomplish).

I've been driving the car for several months now (over 2,000 miles) with no issues. Well, I did forget to put the o-ring for the dipstick tube in. So I did yank it out several times to try and stop the leak. Luckly, I looked at the old transmission and saw that the o-ring was still in it. I pulled it out and put it in the new one and the leak stopped.

The transmission has a 1 year warranty. I plan to put a few more 1,000 miles on it and have it professionally flushed and put in that high dollar fluid. Hopefully, it will be good for over 100,000 more miles.