Kickdown=Clunk=Transmission Broke!
 

My SEARCH produced no result.

1985 MB300CD Turbo w/ 221,000 km. Here's what happened:

The car is running under normal operating temperature. I pressed the accelerator hard to kickdown to merge onto the H-way and all of a sudden, CLUNK sound from the tranny. From then on I get all rpm but "no full-engagement" on the gear. I say "no full-engagement" as I was able to coast along with partial-engagement. The car appear to be stock in one gear and can move/coast the car very slowly while modulating the accelerator.

What do you think went wrong?

On my 1984 MB300DT, at 180,000 km. I completely lost all forward gears and the transmission had to be rebuilt.

These trannies are costing alot of $$$!

:mad:

Is reverse normal? If it is, I'd look to the B2 piston and it's "rod".

Yes, reverse is normal. The B2 piston you're talking about, will it require removal of the tranny?

This gives you the general idea (although on a 126): http://business.baylor.edu/Richard_Easley//autofaqs/b2piston.htm

On a 123, some have done it with the trans in the car by dropping the rear support and, I believe, loosening the exhaust and manhandling it.

There was a recent post on the B2 in a 123, changed out with the tranny still in the car. Check the "search" with <B2 and 123> in the field and good luck.