Transmission not staying in Park?

[Jeff Wilk]

So......here's the issue....1975 Eldorado....yesterday, the first time i had the car running since having the dash out, when I put the car back into PARK on a slight incline and withiut the parking brake on it started rolling backwards. While doing that I also heard a ratcheting sort of sound as id some lock mechanism in the transmission was trying to catch but would not.

When I had the dash out one thing that had to be removed and replaced was the dash shift indicator mechanism. Part of that has this small bracket bolted to the steering column shift collar that rotates as you move the shft lever. Now, before removing it I had always noticed that the pointer never fully lined up with the letters on the dash. So when I replaced it I made sure that adjustment was made too.

I cant see how that adjustment would be causing this but thought Id mention it.

I also had 2 broken speedo cables  ....one from trans to cruise unit and other from cruise to dash. I replaced it with a new one and bypassed the cruise unit running it direct from transmission to the head unit in dash. Works fine.

Any other ideas?  What to check for?

The trans did have a full rebuild at AAMCO about 5 years ago before I biught it and had the real good warranty that transferred to me. Problem is finding an AAMCO with someone who actually knows these transmissions and wants to do the warranty work.

Jeff

[wbdeford]

It sounds like your shifter is just a little bit out of adjustment such that you almost get the lever on the transmission into Park, but not quite.  The "tooth" that engages to lock it in park is in just enough to give you the ratcheting sound, but not enough to hold it. 

The shop manual has an adjustment procedure.  Do you have one?  In the 71 manual, it is the very first thing listed under SERVICE INFORMATION in the TRANSMISSION-ELDORADO section.

[Jeff Wilk]

Thanks. I do have the manual and will check that out first before taking the dash parts off again as all thise plastic/chrome trim bits dont like being disturbed!!!

Jeff

[76eldo]

It's not going to be a dash related problem.
The shifter linkage needs an adjustment and the bushings in the linkage could be worn out too.

Brian

[wbdeford]

If you reach down under the hood from the driver side to find the shift lever on the transmission and pull it toward the front of the car, I imagine you will feel it move slightly and click into Park.

[TJ Hopland]

90% chance its worn bushings in the crank arm.   Its a bracket on the engine side of the firewall that changes the direction of the shift linkage from vertical off the column to horizontal to the transmission.   Its not much different than the RWD design but for some reason wear in the Eldo version is a much bigger problem.

Its come up here before.   Many years ago I did a write up when I repaired mine.   I was not able to find any OE parts.   These must not have started wearing out till well after the factory was supporting em so there didn't ever seem to be a lot of replacement parts made and not enough demand for aftermarket to get involved.    I repaired mine using bushings from a universal door hinge bushing repair kit.  It took a little custom fitting but it wasn't too bad of a job.

There were 2 styles of that crank assembly.   Reliability or availability of parts seems to be about the same for both.   It must be the different angles required for the FWD that caused the wear in some cases.     

[Mike Josephic CLC #3877]

TJ is there a chance you still have a copy of the article you wrote
and if so, could you post it here?  Thanks.

[TJ Hopland]

I don't still have it.   Seems like this came up here within the last year and the person that asked the question wrote about how he did it.    There were also some part numbers given.    Sorry my memory isn't better about how I did it or to narrow down how to search here. 

Basically there is a bracket that bolts to the firewall,  its kind of a U shape and has a couple holes in that that a shaft and crank arm pivot in.  One end is a plastic bushing that is also what holds the shaft in place via a recess in the shaft and a ridge in the bushing, this one does not seem to wear, its the other one or lack of one that has the wear problem.  That is where I and a few others have found you can fit one of the door hinge repair bushings.