sporatic loss of OD and converter lock up

[Galen]

Occasionally, my trans will for no reason shift out of OD and into 3rd gear. If I kick it in neutral and do a quick kill of the engine, it goes back to working fine. I have even flicked the key fast enough to not require use of the starter, so I am pretty sure it is electric related. Any ideas what it could be?

Oh yea, 95 GTP with 4E60 trans.

Thanks all!

Galen

[sharkey]

you must mean a 4t60e.

does the check engine light come on when this happens??? if your car is not obd2, find out how you can read the codes off the ecm, usualy its just jumping 2 pins on the diagnostic plug. find out if there are any codes.

it deffinitly sounds like an electrical problem. this can range from the ecm to the wiring itself, to the solonoids in the tranny. it should be setting a code when it happens if it clears up right after shutting the key off (it would set a soft code, that means it clears it when the key is turned off).

[bszopi]

You need a scan tool to read a 95 ECM. GM took out the pins to allow for "jumping" to get the codes in 94.

[Vetter]

My 1994 GTP does the exact same thing!

Things I've changed so far:
VSS
IAC
Cam Sensor
Timing corrected(The cams were off)
shifter solenoids
TCC switch
Had the tranny completely rebuilt, w/ new Torque converter.

And it still does the same thing, drive excellent for a while, then drops out of OD, and the TC won't lock up, until I shut the engine down, and re-start it.

HELP!!!!!! I don't know what to do next. I don't want to drive the car, in worry the new tranny will fry if I drive it in 3rd, and no lock up.

[Galen]

Thanks for letting me know what I don't need to change. I hate you spent all the $$$$ and are still having the troubles. I just finished with my B.S., so may have time to try to trace the problem down later this month. If I find anything, I will be sure to let you know!

Galen

Oh yea, I have changed the ECU in my car chasing another problem and the problem persisted, so don't try changing that.

[Quinky]

Could be the lock up valve in the valve body is worn out..

[Jman]

TCC has a signal from your brake switch to kick off "lock up" when you hit your brakes. If the switch is out of adjustment, it will cause your tranny to downshift out of overdrive prematurely. Take your car down the highway and lift up on the back of your brake pedal from underneth, and see if the convertor locks. Thats a quick way to start. If not, there are other checks as well, but try that first.

[Quinky]

TCC has a signal from your brake switch to kick off "lock up" when you hit your brakes. If the switch is out of adjustment, it will cause your tranny to downshift out of overdrive prematurely. Take your car down the highway and lift up on the back of your brake pedal from underneth, and see if the convertor locks. Thats a quick way to start. If not, there are other checks as well, but try that first.

not a bad idea.. The brake switch isn't a real commen problem... I'd have the computer scanned for codes.. It definatly sounds electronic..

[Vetter]

I tried the brake switch, but the computer is shutting it down, until I turn the key off, then on.
I had the computer scanned, and I'm getting a PO705 code, I replaced the MLPS, so now I have to beleive it's internal trans pressure. The guy who rebuilt my tranny, refuses, and says it has to be a loose wire some where, and he is going to charge me $70 an hour, to find the loose wire. So my next step, is going to bring it to a guy, who can put it on a diagnostic, and tell me what the Torque converter slippage is, another $60!

[Quinky]

Tell him to check the wiring harness right at the mlps.. the wires like to break and you wont always see it...

Have someone hook a scan tool up to the computer, run the car through all the gears and make sure that the computer is reading all the right gears...

[Vetter]

I replaced the MLPS, because the wires did look to be pulled out of it a small amount, but that didn't cure my problem. I have gone thruogh all the wireing, and haven't been able to find any loose wires. I am bringing the car to a guy, who can put it on a diagnostic, and tell me if the TC is slipping. My only guess at this point.

[Jman]

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=43998&item=4517674513&rd=1

Check that out before you give anybody else your hard earned $

[DEI37]

I have this problem from time to time. Mine sets the check engine light, and it's a engine misfire. Extra load causes the trans to downshift to third, and/or keeps the TC unlocked.

[Vetter]

I have this problem from time to time. Mine sets the check engine light, and it's a engine misfire. Extra load causes the trans to downshift to third, and/or keeps the TC unlocked.

Just courious, will it re-set itself, or do you have to shut off the engine, and turn it back on, before it will go into OD again?

[BoringLumina]

Same problem here anybody found resolution?

Guys,

It was cold out this morning (5°F) and my car didn't shift into OD or lock-up for the whole 37 mile drive into work. The difference is that today the check engine light did not come on as it usually does at about 8 miles into the drive. Pulled into a gas station 1 mile from work and turned car off then back on to check tranny level. Well the oil is darker brown than it used to be, to cold to smell anything. So then when I pulled out I had all 4 gears and lock up and CHECK ENGINE. Car is a 95 Lumina with 193,000 miles. The car also has something like the TCC shudder. Usually the check engine light comes on 1 mile before the shudder starts. It was actually nice to drive into work without the shudder but the high engine RPM's makes me nervous as does an ailing transmissioin.