126 transmission intermittent no reverse or park - PeachParts Mercedes-Benz Forum

gbrebes · #1 06-16-2008, 01:28 AM

I have searched multiple times for the answers to an intermittent problem with the transmission on my 1984 300SD. In the beginning, after I had driven to my destination the car would not shift from Drive to Park. It would go to Neutral, but stop at Reverse. This would only happen rarely, so I would shut off the car in Neutral and drive out of the parking lot without putting it in Reverse. Then it started to happen more often, so I consulted this fine forum and I decided to change my shifter bushings. Upon inspection, my old bushings were not very worn at all, but I replaced them anyway. The transmission not going into park after a drive came back, so I then inspected the rubber hose that is connected to the transmission modulator valve. It looked old and was disintegrating, so I replaced it.
The transmission worked as it should for a while, then the "not shifting into reverse or park" started happening again. This time I pulled apart the shifting linkage and started to fiddle with the small black plastic lever that attaches to the metal shifting lever that is attached to the transmission body. I squeezed this plastic lever and the larger metal lever that it is attached to together and I heard a click. I could now push the metal lever into the reverse and park positions. I put the linkage back together, but I still get the "won't shift into reverse or park" situation intermittently.

Does anyone know what this black plastic lever that is attached to the transmission is called?
Does anyone know what can be done to alleviate this problem other than a rebuilt transmission? The car has 198,000 miles on it.

Thanks a lot for any help and sorry for the long post,

Gilbert

gbrebes · #2 06-17-2008, 02:26 AM

Have I really stumped the experts? Or is my query just too complicated and hard to diagnose?

Please excuse the shameless bump, there are a lot of posts up in here.

Gilbert

turbobenz · #3 06-17-2008, 06:32 AM

maybe the linkage needs to be adjusted

gbrebes · #4 06-17-2008, 06:59 PM

Thanks for the suggestion, I'll try that.

Giblert

81300sd · #5 07-27-2008, 07:21 AM

Have you found a solution for that yet?

Mine before the rebuild was doing that. Shut the car off and it would then shift into park.

My ATSG manual says its a sticky governer. Not sure, my trans at 229,000 miles was completely wasted. The K-3 clutch pack was totally worn out and the planetary gear assembly was busted. Good thing for a donor trans.

gbrebes · #6 07-28-2008, 01:15 PM

Hello,

No, I have not found a solution yet. My symptoms are a little different than yours in that even when I shut the car off, it still will not go into park or reverse. Every time so far though, when I drive to my next destination, the car will go into park. It seems at the moment to be related to the car being warmed up or not. I searched deeper into the archives and found this thread along with a link to another thread which seems promising.

http://www.peachparts.com/shopforum/showthread.php?t=225893&highlight=tranny+reverse

I am hesitant to start pulling things out of the transmission at this point because the problem is still very intermittent. I will probably try a fluid/filter change first and see if it helps at all.

Thanks for bumping this topic back to the first page, I always feel guilty for doing it myself on a thread that I have started.

vstech · #7 07-28-2008, 01:21 PM

Heck, why feel guilty? most of us techs have a short attention span, if it's not on the upper half of the first page... it's gone to us.
on my 82D I had a similar problem, I could not shift to R or P, and if I put it in N then revved the motor, I could then pop it into P, but it felt weird, like it would pop back out if I left the car running... it turned out to be a totally worn out drum and other issues that were not repairable with a rebuild even!!! I had to get another tranny to fix. good thing I had a 4 speed sitting around to throw in.