Sickinger

I am thoroughly stumped on this issue, and any guidance that can be provided will be greatly appreciated. I have a 1992 Plymouth Laser N/A with an automatic transmission that has given me nothing but pain. Quite a while back, the transmission crapped out on me when I was driving around in D.C. I was going around 70 and the car felt like it hit something in the road and the rpm's shot up real high, and the only way to continue driving was to put the car in 2nd and crawl back to Norfolk. I had the transmission diagnosed at that place on Witchduck right off of 264, but they would only do an external diagnostic and wanted $300 to even go in and take a look at what was wrong. Being in the Navy, that was a little too rich for my blood at the time so I ended up buying a used (but assumed good) transmission from DSMTrader. It was a mistake, but I felt there was a chance that it would work out. In putting the new tranny on the car, the timing became off and when the car was started up, some valves were bent. I ended up getting a U-Wrench-It head and putting it on, but it never really worked. I heard a whole lot of ticking and couldn't resolve it. I finally gave up and took it in to a mechanic. The mechanic was able to put the engine back to where it is running great, and then the bad news, the transmission was crap. The guy had another transmission available so he put it on, and he tested it and called me saying it was ready. I went to pick up the car, it sounded great. I went on a test drive and had the O/D on. I got up around 70 and the car had shifted all 4 times and was running very smooth. Then it seemed to lose hold on the gear and shifted very hard back into third. The car went back into O/D briefly but then fell back into third and stayed there. I turned around and went back to the mechanic. When I pulled up and put the car in park, the idle seemed to be surging. It would climb up, then fall and it kept doing it. I asked him to put a Translab shiftkit and a new end clutch set when he had the car, which he did. He told me that the end clutch kit might fix the problem but it didn't. As for the surging idle, he said that it was an air sensor and that he could put another one in there. When I went to pick up the car again, and test drove it, same exact thing. The tranny fell out of O/D but didn't even go back into it, it just stayed in third. I turned around again and took the car back. To make it even worse, when I pulled in and put it in park, the idle started doing that surge thing again. It won't hold a steady idle, it just keeps climbing up and falling down. This time, the mechanic told me that he would have to take it to his friend to see about it. Three weeks have gone by and I hadn't heard a word until today. I called him up and asked what the deal was I was told that the transmission had been taken completely apart but there was no reason why the car would not maintain the O/D gear. So my questions are this:

After looking over a completely field stripped transmission and finding no probable cause for the car to not maintain O/D, where else could the problem be?

What can I do about this revving idle problem, and how much pain will I have to go through to fix that?

Thanks for getting all the way through this post, and I appreciate any help or advice that anyone can give me. I'm about $2,600 deep in this project and would hate to give up but I am running out of options.

g S x

Idle surge information:
http://www.dsm.org/how-tos/tttt/tttt3.html

i'm not too sure about automatic transmissions, but its possible that the transmission computer is acting up.

HatefulMechanic

cracked case losing pressure on the end clutches.


yet another reason you should have had a good tranny shop fix it to start with....

bmwisthekey

read this
http://vfaq.com/index-main.html

on top click link for intake then scroll down to the links about idle surge.

not shure whats wrong with the tranny they have some auto tranny info on that site as well. typically us dsmers try and stay away from the auto trannys in them as much as possible

Sickinger

Thanks for the links and the all of the tips so far. I hear you on the whole auto tranny thing, but I'm kind of stuck for now. I've posted this question on a few other sites, and a few people are coming back with TCU. Could that cause the problem with maintaining O/D?