Trans Slips in Park and Won't reverse

[scott863]

My '81 with 3 speed auto makes a rubbing noise on the shifter when moving from Drive to Park (resistance increases as well), and reverse won't select at all, it worked fine 3 days ago. I'm the 2nd owner and it has 80k original miles.

When the car is put in park, if it's on any sort of incline it will roll forward when the engine is turned off. Thankfully the parking brake works very well.

I've replaced some cracked vacuum hoses in the engine bay, and I know the trans uses vacuum hoses for certain duties as well.

I have the monster 1200+ page Porsche Service guide, but the guide doesn't mention this friction issue, or rolling when in Park.

I'm much more familiar with manual trans.

If it turns out I need a new trans, how difficult is a swap to later 4 speed auto?

Thanks,

Scott
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My posrche history

1. '74 914 1.8
2. '66 912
3. '69 911 E
4. '86 944
5. '87 944
6. '81 928

[IXLOR8]

Any update with your trans?

[scott863]

I finally got underneath the car tonight, there's a decent amount of trans fluid leaking. Also, my shift cable looks like it's in pretty bad shape.

I think the non-reverse and rolling in park have to do with the trans shifts from D to N, but it never actually gets into R or P.

I'm going to clean it up, bring fluid level to the proper one, then try to find source of the leak.

Anyone have any experience with a bad shift cable and tracing leaks? I have the full multi-volime Porsche Service guide, but need to look again for anything about leaks.

[scott863]

Had a better look today while someone shifted through the gears, for R and P the shifter cable goes from pulling to pushing, and there is a break in it, and it just flexes, but doesn't change gears. For a trans, $200 shifter cable beats a rebuilt trans, especially since I plan to swap in a 4 speed auto in the future.

[JandeVries]

Seems to be the cable, but as far as the leaks, just screw down the pan,after dropping down the ATF oil in a bucket with measurement( should be about 2 liters) and replace both the gasket and the filter(mercedes S 126 part). See how much oil there is in the bucket and top it up again at the cold level,and take it out for a spin.
Check when warm again if the oil is at the warm/hot level.
If all the gears work fine, you're done.
If the R still doesn't work, there is a adjustment nut at the passenger side, don't know exactly the location from memory anymore, but it is an adjustment nut, and let's say if you put a wrench on it at 12 o'clock, you can try to set it at 5 past one, see if it helps, but sincerely, if adjustment is needed it looks like a revision or replacement of the automatic transmission is in need in time. Been there, done that.

[scott863]

Hej Jan, hoe haat met?


I started the car up (on the jack stands and ramps in front) and it ran fine in reverse with me selecting it manually. One question, what is that lever on the passenger side of the transmission case?

[MPDano]

Originally Posted by scott863

Hej Jan, hoe haat met?


I started the car up (on the jack stands and ramps in front) and it ran fine in reverse with me selecting it manually. One question, what is that lever on the passenger side of the transmission case?

Hi Scott,


That lever should have a return spring hooked up to it. It is connected to the Bowden Cable that runs from your throttle under the hood. I am currently still having problems trying to get mine adjusted, but I believe my cable housing compressed somehow, which is why I have almost 2 inches of slack in mine. That lever you are seeing has an adjustment on it to adjust this Bowden Cable, but just fine (small) adjustments.

[Danglerb]

Leo, this thread is more than 2 years old.

[MPDano]

Can't we all just get along?