Transmission troubles... if its not one thing...

[Kooterskkar]

Aright, first off its not for a lumina, its for a corsica, but no one ever goes to the corsica section, so im postin it here.
'89 corsica 125k miles Th125C auto transmission. I think the early luminas had those too didnt they?
This thing was low on fluid for a while, about a month I think. And I think it did some serious damage in that time. It has always kinda slipped going into third gear, so I changed the fluid, and filter. I think I made it worse though. I have to let off the gas, or the engine will rev up before it will go into third now. First off I dont think I put the right amount of fluid back in there. The manual sai 3.8L... Kinda strange I though but OK. Checked fluid after I poured in a gallon of it. WAY low on the stick. So I put in another quart. Moved up a little but not a whole lot. Put in anoter quart, now its a half inch above the full line. Ive checked it every which way I can. Drove it around the block and checked it, still the same, drove it to the mall and checked it, still the same. Drove it home and let it sit a half hour or so, then cut it back on, put it in drive, then reverse, then park again. Checked it, STILL high. Wtf? It was way too low, I added 2 quarts and all of a sudden its too high? Is there something im doing wrong here?
Does anyone know EXACLTY how many quarts of fluid it takes to refill a TH125C after a change? This is really pissing me off.

[dwalmop]

I thought it was about 3 qts. after fluid and filter change. How high on the dipstick is it?

[richtazz]

a half inch above the line is approx 1/2-3/4 of a quart high. drive it a bit and check the fluid. IF you see foam developing, you're too high and need to get some out. A cheap siphon kit hose stuck thru the dipstick tube will get the extra out easily. IF you don't see any foaming of the fluid, don't worry about it too much, but I would still get it out if it was mine.

[Kooterskkar]

Yeah but thats the thing, the manual said 4 quarts, but it was low before, and I know more than 4 quarts drained out of it. And when I refilled it I poured in 4 quarts, and it was too low. So i added more and it was still low, added ONE more quart and all of a sudded its too high?
If it was too high would it cuase it to slip like it does?

[tblake]

drive the car for a while, get out, leave it running in park, and then check the tranny fluid, this should give you an accurte reading.

[jeffcoslacker]

If the pump is not able to create enough draw at the pickup the pan will overfill with fluid and make a correct level hard to acheive.

[Kooterskkar]

And what exactly might cuase that?

[Fireplug]

First what type of trans fluid did you use? And sec after a trans filter and fluid change you have to put in 4 qts of dextron 2 transmission fluid. A overfiled trans will slip in gear.

[trannyman52]

Dextron III is the proper oil ,,,,the 125-C can,,,and advised to be some-what over-filled,,a quart is O.K. helps oil planitary sets,,,,the "slip" is probably caused by damage to the direct clutch in the tranny,,,not good to be run low on oil,,,,sorry!!!!!

[jeffcoslacker]

Originally Posted by Kooterskkar

And what exactly might cuase that?

Worn pump/internals

[Kooterskkar]

I figured this thing was fucked when I first got the car. It has ALWAYS slipped a little going into third. I tried siphoning out some fluid yesterday, just made it worse. So i put it all back... and now im pricing a manual transmission, clutch, flywheel, clutch master, lines, and all the other parsts ill need (linkage, shifter, pedal) I can rip from a JY car.

[jeffcoslacker]

Was there a clutch pivot available that would work with that car? And is an ECM change called for also? Just thoughts.

[dwalmop]

sounds like a BIG job.

[Kooterskkar]

Yes I can rip all the shifter parts out of a 1st gen cavalier, OR if I get lucky and find a manual corsica i'll get it out of there. BUT... manual corsicas are pretty damn rare. I dont think an ECM swap is required, but I did think of that, and im gonna grab one just for good measure. I shouldnt need it though, cuz this car doesnt have a park/nuetral rev limiter, which would be the only thing to worry about I think.

[richtazz]

you'd also need a wiring harness, as the VSS sensor and neutral safety switch are different in a stick and auto. GM 3-speed autos are a dime a dozen, and pretty tough. Unfortunately for you, the only way to kill one is to overheat it, which happens when they are run low on fluid. IF you suspect your trans is shot, replace it with the same unit, swapping for a manual is WAY more involved than you think, especially in a computer controlled vehicle.