wont go into reverse or park unless...

[seafood54]

My wife's '85 300D, aka "Pain" continues to vex me. Now...it refuses to go from drive past neutral, into reverse or park, unless you shut the engine off. Then everthing acts normally. HELP please.. and thanks.. Franko

[seafood54]

let me ask/describe this a different way..

My wife's '85 300D shifter will not go from neutral into reverse or park with the engine running. Turn the engine off, and everything functions properly, the shifter passing from drive through neutral into reverse and into park. But not with the engine running... Any thoughts? thanks... Frank

[SD Blue]

Possibly shift linkage bushings? Does there seem to be a little excessive play in the shift lever? (www.**************.com has a little tool for installing them.)

[Slcom1983]

Could it be with the mechanism that prevents doing the same while the car is moving?

[seafood54]

I dont know if there is such a mechanism, and I would think, if there was one, it might be called a transmission shift interlock, but I've done searches regarding these terms, but found only threads refering to the dorr locking system.

Anyone know if there is a 'transmission shift interlock' system?

[david s poole]

there is a neat little option built into the valve body so that if someone were to try and put car into reverse when it was moving forward at 25mph[i think]the lever will not move past neutral[bingo you just saved your trans]this consists of a valve with a solid steel plunger that pops out of the secondary valve body when set speed is reached and then goes back when slowing down below 10mph.unfortunately this is accessed by removing the trans pan and first taking down the valve body and then removing the big plate with the secondary valve body on it.you will have to dissassemble the reverse safety valve and clean out the dirt that is causing it to stick[yes dirt] while you are there good idea to remove small v/body from plate and clean out the filters for the govenor[they will be in the underside of the small v/body.one more thing replace the main plate gasket as you go back together.[the original is probably ready for the smithsonian] by the way the reason you can move the lever when engine shuts down is because no more pressure from front pump.david poole european performance dallas tx.

[pmckechnie]

I had this exact problem on my 91 300D. The problem was the governor was hung up. This is an easy yet hard fix. The governor is behind a cover on the left rear of the trans. Remove the cover, remove the governor assembly, clean it, reinstall and problem fixed. (On my car anyway). The hard part of the job is getting the governor out of the trans after the cover is removed. There is a snap ring that is hard to get to with out a special tool. My local trans man didn't even have one. I got mine out just using whatever I could find.
Good luck.

[OMEGAMAN]

Originally Posted by david s poole

there is a neat little option built into the valve body so that if someone were to try and put car into reverse when it was moving forward at 25mph[i think]the lever will not move past neutral[bingo you just saved your trans]this consists of a valve with a solid steel plunger that pops out of the secondary valve body when set speed is reached and then goes back when slowing down below 10mph.unfortunately this is accessed by removing the trans pan and first taking down the valve body and then removing the big plate with the secondary valve body on it.you will have to dissassemble the reverse safety valve and clean out the dirt that is causing it to stick[yes dirt] while you are there good idea to remove small v/body from plate and clean out the filters for the govenor[they will be in the underside of the small v/body.one more thing replace the main plate gasket as you go back together.[the original is probably ready for the smithsonian] by the way the reason you can move the lever when engine shuts down is because no more pressure from front pump.david poole european performance dallas tx.

Dayamn I'm impressed. Is that feature on all mb automatics or just some.

[david s poole]

it was on all that i'm aware of. did you know about the second fluid pump in line with govenor at the back so that you can tow start the car?pull to 35mph and slip into drive and voila! spins engine and starts.i think they dropped this in 1993 something about needing the room for more gears.david poole european performance dallas tx.