Got a 93 with 3.1 automatic, basically runs really good but have one issue can't figure out. At highway speeds act like it should best I can tell, but when slowing down to turn or stop, it acts like a manual without the clutch pushed in. However when you get slow enough, around the time it shifts into first, it immediately returns to normal.

I will add it does stay somewhat higher idle until the slower speed is reached, so could be an idle issue, but if the clutch not releasing the idle would follow the speed, like a manual etc.

Just got this a little while back and the trans fluid looks dark as 15/40 diesel oil, but with 200+ on the odo, I'm concerned about trying to service it at this point without knowing the history. I did pull a few quarts out through the fill tube just so I could at least give it some fresh blood without removing too much clutch material, but not well versed in trans.

Sorry for long post, any ideas would be appreciated.

 

Here's another weird thing I just noticed, in drive it slips sometimes in the lower gears like just starting out. But never in OD, lol

 

Sorry, what Vehicle do you own?

Some 1993 Vehicles have THM700-R4 Transmission, and some have a 4L60E Transmission.

 

Not sure, read on here and believe it's a 700r4, but it's just a stock 92 rs 25 anniversary 3.1 automatic with overdrive. I can get under there and look for some numbers if that would help.

Also this morning when we first crunk it up it lurched forward just a little like it was in gear, but it's an auto in Park.

 

I'll defer to those with more AT experience, but it sounds like you are describing a lock-up torque converter that is not unlocking properly under all circumstances.

 

10-4, thanks

 

At cruising speed / throttle, you should be able to tap lightly on the brake pedal...just enough to light the brake lamps...and you should feel the converter unlock, and see the rpm increase on the tach or hear it. If it's not unlocking, that's a problem.

I had a '90 Cavalier that had the TCC fail, or more correctly was just worn out. I disabled the TCC, and used it as a straight 3 speed automatic (was a 3 speed with lock-up) thereafter. The car was too rusted away to invest in fixing it for an extra mile per gallon here and there.

There can be some other reasons for this. Again, auto trans is not my strength. Lets here what some of the real experts here think.

 

I put a new icm on the distributor, I had already done a full tune up, and now it seems to be acting right.

The old icm was working but at times after warming up it would sound like it had a racing cam in it, but it doesn't lol.

Reckon the ign system being a bit off would cause tranny to act up a little?

Don't know but seems ok for now, other than still moves forward a bit on crank ups.

 

Engine Load, and certain types of malfunctions (Poor Engine operating, miss-fires, Etc) will cause erratic TCC Lock-Up behavior...or no Lock-Up at all.

 

Awesome, thanks for all the info. Seems to be ok now so will put some miles on it see how it goes.