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Hey!

I just found this forum, and I have had absolutely NO luck elsewhere. I have a 1990 Geo Tracker 4wd with a 3spd auto tranny (TH180). I have owned it about 1.5 years, now. When I bought it, the tranny shifted fine. After about 4 or 5 months, the tranny began a delayed shift into 2nd when cold. That progressed over time to NOT shifting into 2nd when cold. The kickdown cable was inop when I bought it, and thought that it COULD be contributing... so when I rebuilt the engine bback this summer, I pulled the tranny and changed the kickdown cable. When I got the Tracker back together, the tranny shifted PERFECT for the first 3 or 5 trips around the county to run the engine.

Within weeks, the no-cold-shift returned. Now. Let me describe the conditions.

When cold, the tranny selects 1st and reverse fine. When driven, the Tracker accelerates fine with no sign of slippage. When it comes time to shift into 2nd gear, the tranny "shifts" into "neutral"... as if 2nd gear isn't even there. This continues until the engine has been at 180+ degrees for several minutes. THEN, it will not make that first shift into 2nd until the enging is singing along at 5,000 RPM. The shift is not hard... it is a simple smooth shift. Once it shifts into second gear, then it will usually shift fine for the remainder of the trip. Now, if I park it for a few minutes, it won't shift again until I hit 4,000+ RPM.

I once had problems with an old TH350 (GM) where the vacuum hose for the modulator was swelled by oil and there was no vacuum. Had the no-shift symptom. Once a new hose was installed, it shifted great. Now. I have replaced every suspect vacuum hose on the rig.... which means almost all of them. I have also tweaked the engine up to 15" of vacuum. I installed a Calmin cam (slightly higher lift and duration for "torque") and a Calmini header. 15" is the best I have been able to conjure up. I was told that 17" is ideal on this engine. Will an adjustable vacuum modulator (9.5-12") possibly help this problem, or am I looking for an internal problem?

I just spent $1600 on a tranny rebuild at a shop for my Jeep. Having rebuilt a '76-ish TH350, I think I can tackle this one if need be. I had the engine rebuild on this one and the tranny went on my Jeep in the same week, and I didn't need two projects.

Any help will be graciously appreciated. I have received absolutely NO help from other forums.... auto trannies remain to be a mystery to thousands of gearheads.

Thanks!
Billy (b1pig)

b1pig wrote:

Hey!

I just found this forum, and I have had absolutely NO luck elsewhere. I have a 1990 Geo Tracker 4wd with a 3spd auto tranny (TH180). I have owned it about 1.5 years, now. When I bought it, the tranny shifted fine. After about 4 or 5 months, the tranny began a delayed shift into 2nd when cold. That progressed over time to NOT shifting into 2nd when cold. The kickdown cable was inop when I bought it, and thought that it COULD be contributing... so when I rebuilt the engine bback this summer, I pulled the tranny and changed the kickdown cable. When I got the Tracker back together, the tranny shifted PERFECT for the first 3 or 5 trips around the county to run the engine.

Within weeks, the no-cold-shift returned. Now. Let me describe the conditions.

When cold, the tranny selects 1st and reverse fine. When driven, the Tracker accelerates fine with no sign of slippage. When it comes time to shift into 2nd gear, the tranny "shifts" into "neutral"... as if 2nd gear isn't even there. This continues until the engine has been at 180+ degrees for several minutes. THEN, it will not make that first shift into 2nd until the enging is singing along at 5,000 RPM. The shift is not hard... it is a simple smooth shift. Once it shifts into second gear, then it will usually shift fine for the remainder of the trip. Now, if I park it for a few minutes, it won't shift again until I hit 4,000+ RPM.

I once had problems with an old TH350 (GM) where the vacuum hose for the modulator was swelled by oil and there was no vacuum. Had the no-shift symptom. Once a new hose was installed, it shifted great. Now. I have replaced every suspect vacuum hose on the rig.... which means almost all of them. I have also tweaked the engine up to 15" of vacuum. I installed a Calmin cam (slightly higher lift and duration for "torque") and a Calmini header. 15" is the best I have been able to conjure up. I was told that 17" is ideal on this engine. Will an adjustable vacuum modulator (9.5-12") possibly help this problem, or am I looking for an internal problem?

I just spent $1600 on a tranny rebuild at a shop for my Jeep. Having rebuilt a '76-ish TH350, I think I can tackle this one if need be. I had the engine rebuild on this one and the tranny went on my Jeep in the same week, and I didn't need two projects.

Any help will be graciously appreciated. I have received absolutely NO help from other forums.... auto trannies remain to be a mystery to thousands of gearheads.

Thanks!
Billy (b1pig)  

Thanks for the reply.
Since I don't have alot of experience with rebuilding transmissions, I am hoping that a simple "soft rebuild" (seals and clutches) will fix things up. Thanks for the tips.  

Did you ever solve this problem because I have exactly the same problem  

Well.
Yes, and no.
I took it upon myself to rebuild the transmission. I replaced all the clutch packs and all the seals/rings except for a small accumilator. The tranny now shifts ok. Slow to go into gear, very slow going into reverse, and it appears to engage two gears at once when manually shifted. I can only guees as to the problem at this point. I am just going to replace it with a salvage tranny and take it back apart.  

Just another data point: I have the same problem with my '98 Tracker with 45k miles. If I solve the problem I'll post again.  

I have had the exact same problem with my 90 geo tracker. Its basically losing compression in the engine due to bad o rings Geo tracker did not put the best o rings in. They dry up and crack thus the reason it needs to build up pressure then drives ok. Ill be running it into the ground too expensive for a car that cost me 1500  

Update: I changed the fluid & filter, using Valvoline Max "High mileage" transmission fluid. It claims to be high detergent and to contain a seal & O-ring conditioner. After about a month, the problem is all but gone. A little hesistant on the first shift when cold, but fine thereafter. MUCH better than it was.

Now the lock-up soleniod has gone South..... Oh well.