Mercedes-Benz Forum banner

1985 300td tranny shift issues

2K views 11 replies 6 participants last post by  kent5915 
#1 ·
Hi and thanks for any help

I have owned this 85 300td for 5 yrs now and am getting rather pissed with a tranny issue that has bugged me from the beginning and seemingly is getting worse. I start her up and she generally does not want to go into any gear. I generally have to put her in park and rev the engine to 4000 rpm a few times , then she will go into gear.

Now it is a california 85 but seemingly has 722.315 trany - I think trany and engine maybe out of another car.
Now I have removed much of the californai BS similar to this:
vacuum amplifier on '85 722.4

I have also installed a new Bowden cable

I changed the trany filter and put the best synthetic trany oil that money can buy into her

I also have good vacuum (over 22 PSI)

Now sometimes she will just go into gear after startup but other times no way I have to rev her a few times So - I still have the problem.

I am wondering if it could be the pressure converter (part no 1233001133) - or at least how do I test it.

I guess the other option is its internal in the trany

Any suggestions would be greatly appreciated

Kent
 
See less See more
#3 · (Edited)
I would look at shifter bushings as was stated....wouldn't be vacuum as it would still shift, it can be a few things linkages, Bowden cable, bushings or the transmission its self.....fluid level is very crucial to these trans, to low and it will not go into gear.....check the fluid at engine temperature, idling in park....fluid level should be between the two marks.....confirm you have adjusted all the linkages per FSM.....post some photos of your linkage arrangement, could be a chance something is up with the linkage or hooked up wrong from the swap...

Diy for bushings

http://www.benzworld.org/forums/w123-e-ce-d-cd-td/1417360-diy-console-shifter-bushing-replacement.html
 
#7 · (Edited)
This.

:thumbsup:

Also, disconnect the vacuum going to the modulator. It should shift on time, harsh but on time. If not, then definitively something is going on with pressure.
Maybe one of those K1 or K2 lil piston nightmares....
 
#5 ·
thanks guys

ya I played with vacuum hoses yesterday - thought I had it fixed but then last night when shopping same thing - did not want to go into gear until I rev the shit out of her first

I was going to change the linkage plastic bits but could not seem to get at them - I may order the kit from mercedes source with the tool to change - does anyone have a cheaper place to buy the tool
 
#8 · (Edited)
Sounds like the front pump in the transmission Is weak to me. That's at least if it were a GM product, I would think a MB auto would be the same.
We could get GM automatics to come back to life with a bottle of TransX, when the pump started going out.
But once you start using TransX you have to add it about once every 6 monthes and drain a little fluid out the pan. And then change the fluid ever so often.

 
#9 ·
thanks again

So yesterday i played with the bowden cable - readjusted and took car out for test drive - it shifted smooth and I told myself - problem solved

Got up this morn and low and behold it did not want to go into gear - same headache - no gears (forward nor reverse) until engine ran for a while ugg

Now I stated it would not go into gear until after its been reved for a while - I should specify - it generally goes into reverse after one or two long revs but still does not go into any forward gears until after several long revs

I am starting to ponder - can it be the K1 or K2 spring or how about the B1 B2 or B3 spring - probably in all liklihood its a combination of things

guess I will try trans x first and think about the other possibilities - which springs can be changed without pulling the tranny

cheers And thanks and have a great day
 
#11 · (Edited)
It really sounds like you are low on fluid....the same thing happened to my car after I changed the fluid....after I reeved the fluid got sucked into the converter....happen the next day too when my fluid was low.....topped it off and it came back to life.....if its not the fluid its like others say, its probably the pump...
 
#12 ·
thanks again

I checked fluid again and it was low but by only 250 ml- anyhow added a transmission conditioner (resolone (spell) could not find trans x)

Not sure why when I checked a week ago the level seemed fine - best keep an eye on that one

more importantly- I noticed that my Bowden cable keeps slipping out of position - perhaps herein is the partial culprit - for some reason the bowden cable keeps slipping over the upright pin that attached it to the throttle linkage - I actually noticed it was off the other day - so I put it back in place then I readjusted the bowden cable according to mercedes source manual and it seemingly ran like a dream (okay just a heck of alot better) but then yesterday morn it wouldn't go into gear easily but had to get to an appointment so took my other drive and then in the afternoon when I got home I saw that the cable was off again yesterday

anyhow got up this morning made sure that the bowden cable was in its proper place and she went into gear without having to overly rev her

guess its time to reconstruct the lever (throttle linkage) that pulls the bowden cable - it is held on by a c-clip and I guess its worn too much so that the cable hops over her - probably whenever I hit a bump

no matter great that I am getting somewhere & the trany does feel a tad clunky - maybe getting to be time to change whatever springs and modulator that I can

cheers and thanks for all the great advice from great people
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top