Auto transmission electrical problem

[phillip fair]

My transmission has been shifting great no problems at all. Yesterday I was driving and it felt like it was slipping I pulled off the road it wouldn't go forward or reverse nothing I checked the fluid which was fine. I then shut off the car and started to call a wreaker, I cranked it up and pulled it into drive and tried to drive home to my disbelief it now shifted perfect no problems I drove it all the way home. About an hour I jumped in it again and it started slipping again it was like I shiffted it into neutral, again I pulled over put it in park shut off the engine and restarted it, now it shifts fine with no problems. I know that it is electrical but there is no codes and I haven't been able to duplicate it when I had my scanner attatched. Has anyone run into this before and is there a common solution I really like the automatic because that is what came in me 240SX Convertible and I don't want a stick. If anyone has any answers I would like to hear them

[JeromeS13]

What gives you the idea that its an electrical problem? Mine did pretty much the same exact thing a while back. I ended up just swapping the transmission and putting in a new torque converter. Problem solved.

-Jerome

[rogoman]

Have you run the transmission diagnostic procedure as outlined in the FSM?

[phillip fair]

I asumed it was electrical because when it would do it I can shut off the engine started back up immediately and the problem would go away for several miles. When it did again I repeated the procedure with the same results. I also have an OTC Genisis diagnostic computer and I have checked for codes and there are none. I have driven the car with the scanner hooked up and looked at all of the inputs. I'm going to talk to transmission mech tomorrow and see what he thinks. Thanks for the suggestions. I'll keep the torque converter in mind.

[guyaverage]

I agree that this is most likely an electrical problem, probably the inhibitor switch if I had to take a guess (on the passenger side of the transmission, its connected to the shift connector rod). An internal hydraulic problem usually wouldnt clear itself up completely, reappear without notice, then disappear again. Electrical problems however would do exactly that. If you dont have an FSM (factory service manual) you might want to download it and check out the location of the electrical connections (the 3 right behind the battery, the connection to the ATCU under the passenger kick panel, etc) and disconnect, clean, and maybe gently bend the tabs to make a better connection. If you have never dropped the pan, there are 3 more connections inside there too that can be accessed.

I would make a big bet that many "bad transmissions" have been swapped out when they arent bad at all, but the electrical connections to them are.

[phillip fair]

Finely found the problem. about a thousand miles ago I serviced the transmission with Mobil 1 ATF as it turns out Mobil 1 has alot of detergents in it and it will clean every last bit of sludge out of your transmisson. I ran all kinds of diagnostics on it and everything came back good out of desperation I dropped the pan the fluid and the inside of the pan spotless I was checking the connections inside the transmission and something told me to take a close look at the filter. To my amazment I discovered the the filter was almost completely clogged with sludge. I replaced it with a new one and now it shifts better than it did when I bought it. Mobil 1 will throughly clean the inside of a transmission that you will swear that it has been rebuilt. I'll keep you guys informed if I expeirence anymore problems related to this