300sd transmisson slips pulling off - PeachParts Mercedes-Benz Forum

acrimson300sd · #1 04-05-2008, 06:47 PM

Hello all I am in need of help fast. First off the car is a 83 300sd The transmission was shifting fine no harsh shifts or other problems associated with theses cars. Drove it to work today did great but when I left the car wouldn't pull off it just sat and slipped it finally tried to pull off but I decide to leave it.
I checked the fluid it was normal nice red fluid at full level. It will reverse just fine. I finally got it to pull off slowly and its fine through all gears but slips really bad pulling off if you get in the throttle at all. Never had any problems out of it no slippage at all ever.
If anyone knows what is going on with it please let me know. Could it be a vacuum issue? bad modulator? any ideas please help!!!!!!!!!!!!!!!

OMEGAMAN · #2 04-05-2008, 07:31 PM

You say "I checked the fluid it was normal no nice red fluid at full level"
Do you have fluid on the stick?

acrimson300sd · #3 04-05-2008, 07:37 PM

Yes it was normal not low not over filled and it was clean red not burnt brown

acrimson300sd · #4 04-05-2008, 08:27 PM

Any ideas anyone please help

Rick H · #5 04-06-2008, 12:07 AM

Do search on B2 piston .The part is about $130 and you can install it with the tranny in the car you have to drop the cross member then the tranny will come down enough to get to it .There are to round covers on the passengersside it`s one of those don`t remember witch one. Hope this helps Rick

acrimson300sd · #6 04-06-2008, 12:14 AM

Ok I will do that. Would that be the brake band piston?
Thanks Rick!

Rick H · #7 04-06-2008, 12:44 AM

I don`t know about the brake band I`ve never heard it called that but I`m not sure about that. I had the same problem with a 83 300D not sure if they are the same. It would slip in 1st when you went to take off then once you got roll it would shift fine.There is a up graded piston the old ones come a part. There is a sleave that needs to be replaced too. I got the parts from Phil . He will get you the right stuff you need if you decide that`s your problem. It sure sounds like it to me. If you pop that cover off and it comes out in pieces you know thats your problem. There is good info on this site about it this is where I found out about it.

acrimson300sd · #8 04-06-2008, 12:52 AM

Thanks again Rick that sounds just like what I needed. The Fastlane listing calls it a brake band piston. I think it acts on the froward band in the transmission allowing it to grip the drum thus making the shift. Which is similar to a servo in a GM 700r4 which I am unfortunately very familiar with.

Rick H · #9 04-07-2008, 12:16 PM

I ran into a good pictorial of this job on the www.dieselgiant.com

leathermang · #10 04-07-2008, 12:45 PM

First try a couple of cans of Trans-x...
do a search to find others that have used it..
not a snake oil.. it can help if your problem is caused by varnish build up in the tiny holes in the trans valve body....

acrimson300sd · #11 04-08-2008, 01:59 AM

The B2 piston was in about 3 parts totally destroyed so I don't think trans-x is the fix this time. Thanks to everyone for responding so quickly
Also I am wondering when replacing the sleeve with the plastic one there is a black seal at this sleeve but I cant seem to find anywhere to buy one not on Fastline nor dieselgiant. Does this seal have to be replaced when replacing the sleeve? I have found a new outer o-ring seal but not the inner one. The seal can be seen here http://www.dieselgiant.com/merdedesb2piston52.JPG Any help please?

Rick H · #12 04-08-2008, 09:57 AM

Right on .Glad to hear that was your problem beats having to have the tranny rebuilt. Of all the stuff I`ve learned from this forum this is the one that`s saved me the most doe.I`m pretty sure that I did replace that seal when I did mine it`s been a few yrs ago.You might check with Phil again just to make sure he`s not missing something. I know I got all my parts from him.

blindwolf · #13 04-08-2008, 10:15 AM

Does the new plastic bushing need the sleeve or is it just part of the old style metal bushing? Russell usually sends everythjing you need to replace in one of his kits. Give him a call, if you bought the part from him.

acrimson300sd · #14 04-09-2008, 04:59 PM

I want to thank everyone again for your response!
I ordered the parts from Phil and they are on the way. It is actually costing me more to do the piston than a full rebuild but a ton less time. It was about 170 for all the piston parts and I can get a rebuild kit local for 130 and the bands relined for 15ea. I am glad to spend more money for less work thats for sure!!