Transmission went south

[rg2098]

Well went to the store today, every thing's normal except for the new rust hole I found in the firewall under the battery on my rust free southern body and slicing my finger good pulling goop off the rust. Came out of the store, started my car, put it in D and press the pedal. It revs but I'm not moving, whats going on, I check to make sure its in D and not N and sure enough its in D. So I try to move the shifter a few positions and try again, shut the car off then restart, check the fluid (full), disconnect the kick-down switch. NOTHING WORKS. I was able to nurse the car the mile home.

-reverse works completely normal
-will not shift into first, can get it to catch slightly around 3000 rpm with the brakes depressed (load) and
s l o w l y get it to move until it gets to the point to shift into 2nd
-once nursed up to speed all the other gears shift flawlessly with no slippage.

I just replaced the vacuum modulator. 1-2 was tad harsh, 2-3 slipped a bit maybe 200 rpm, 3-4 was fine.

Someone please tell me whats wrong and that its a simple adjustment or spring.

Where can I get a quality rebuilt transmission?

[mplafleur]

Sounds like the B2 piston broke. I hear it has been replaced without removing the trans in a W123. A W126 has more room though.

See:

http://transmission.articles.mbz.org/b2/

[Astroman]

Stop spinning up the engine, wearing away your B2 band and running the metal bits from the B2 piston through the transmission! Ok, that said, go read all up about the B2 piston replacement, set aside a saturday morning, about 200 bucks, and get it done. Don't forget to change the transmission filter, fluid, and do the K1 accumulator spring upgrade while you're there. Then you will once again be a happy camper..

[1985 300SD Sady]

Originally Posted by rg2098

Well went to the store today, every thing's normal except for the new rust hole I found in the firewall under the battery on my rust free southern body and slicing my finger good pulling goop off the rust. Came out of the store, started my car, put it in D and press the pedal. It revs but I'm not moving, whats going on, I check to make sure its in D and not N and sure enough its in D. So I try to move the shifter a few positions and try again, shut the car off then restart, check the fluid (full), disconnect the kick-down switch. NOTHING WORKS. I was able to nurse the car the mile home.

-reverse works completely normal
-will not shift into first, can get it to catch slightly around 3000 rpm with the brakes depressed (load) and
s l o w l y get it to move until it gets to the point to shift into 2nd
-once nursed up to speed all the other gears shift flawlessly with no slippage.

I just replaced the vacuum modulator. 1-2 was tad harsh, 2-3 slipped a bit maybe 200 rpm, 3-4 was fine.

Someone please tell me whats wrong and that its a simple adjustment or spring.

Where can I get a quality rebuilt transmission?

From what this says and whatI have seen in previous threads and this one, looks like youll be replacing the B2 piston. Sure stinks about the rust too doesnt sould like such a fun day

[DieselBone]

Yup its the B2. Make sure you read all the threads and get the parts you need. Its an easy job, however I haven't done one with the trans in the car. It shouldn't take longer than a day to finish if you have all the parts.
Good luck! Keep us updated!

[rg2098]

I will order the parts today and they will be here tomorrow. I completely forgot about the B2 piston trying to figure out what went wrong. I willlet you know how it comes out.

Note: K1, filter, fluid all done within the last 500 miles.

What would I do without you guys and this forum!

[rockhopper]

Mine did the same thing a month ago...had my local mechanic replace the B2 piston and 2,000 miles later it's shifting great.

[d.delano]

Hey Rockhopper- bet I can guess who your mechanic is(Rick?). Why did it take 2k miles to shift well again?

[rockhopper]

sorry, should have clarified...it's been 2,000 miles since the repair and it has been running/shifting great since the repair. Yes, Rick installed the B2.

[d.delano]

Sweet. How much did it set you back? It's a relief knowing he can do it successfully, as I may have to do the same you never know. My car shifts well now w/ a slight flare from 2-3.

[rockhopper]

sent you a PM.

[rbarnes]

My '83 300D has the exact same symptoms. It happened while I was sitting at a red light. Will not engage in first without revs and feathering the throttle, shifts and runs fine once it makes that first shift. Pulled some fluid and put in some Trans-X without success. Will definetly check out the B-2 piston. Thanks for the thread, I hope it gets me on the right track.

[rg2098]

Yup, it was the B2, new parts will be here tomorrow. This pile of parts was one contained unit at one time. Definetly a catastrophic failure of the B2. I remember hearding a pop when it put it in park when I got to the store. Amazing I could hear it in the passanger compartment with the engine running.

THANKS!

[rg2098]

For the record, it was not that difficult to do,

1)remove engine shock mounts
2)remove engine mounts and lower engine until resting on body
3)remove rear transmission mount
4)proceed with removing the B2.

I was able to get plenty of clearence with all the mounts out.

[mplafleur]

Originally Posted by rg2098

Amazing I could hear it in the passanger compartment with the engine running.THANKS!

Then it was your dad that broke it?