Weird Tranny trouble and more, please help!

[GGrays1999]

Car: 1995 Lumina, 3.1 V-6, auto, fully loaded except leather. 83,000 Miles

Problems:

1. Not big concern...Turn vent fan on high, has loud groaning sound from under dash. 1,2,3 speeds are ok, 4th really loud. Suspecting bad bearing in blower fan, any other ideas?

2. Getting more concerned....Speedometer quits working once in a while. Well, should say doesn't start working, that is until you smack the top of the dashboard, then it works fine.

3. Low coolant light comes on intermittently even though is full...Never overheats/etc. More on this to come.

4. Tranny problem, most concerning. Going from dead stop, will shudder, say like someone trying to dump clutch in 3rd gear from dead stop. Will stay in first gear until about 10 mph, then shifts up, and then up again fast, like someone dumping clutch. Motor will pull tall gearing, but obviously slow to accellerate. Weirder still, going from stop, smash the gas to the floor, spin the tires(especially if going around corner) shifts PERFECTLY. If cruising, trying to accelerate, it either tries to pull the tall gearing, or will downshift harshly/erradically, whiplash is soooo nice. Absolutely mash the throttle, shifts fine again, including downshift. Suspect: Vehicle speed sensor or TCC Circuit/solenoids.

5. 1,3,4 were happening first, then 2, now I notice this problem. Can drive along with warm air blowing....as I start to come to a stop, the temperature(engine) goes from say about 160 to almost 260, BUT, the hot air stops blowing, and becomes COLD(Or ambient temp). Now, sitting at a stop, temp is high, blowing cold air. Start to move, temperature IMMEDIATELY drops(motor) and air starts start to rise in temp. A/C still works fine. There is no possible way for the motor to rise and then drop in temperature approximately 40-50 degrees in a matter of 3-6 seconds.

My family has owned car since new, regular oil changes, etc, etc. In fact, in last 10,000 miles tranny fluid changed at each shop taken to as precaution, no problems found. Fluid looks perfect. They are afraid to rebuild tranny based on they are unsure if rebuild is necessary or would actually fix the problem.

If anyone out there has any ideas for this problem, please send me a private message through the system on this forum board, or email me directly at GGrays1999@aol.com

Any help appreciated, thanks!

Now, just took car on 600+ mile freeway trip, ran perfectly at highway speeds. In fact, 28mpg at 80-85 mph, sometimes hitting 90. Just don't make shift and it's perfect.

At no time does check engine light come on. Has been to 3 different tranny shops, no answer. Going to run an OBD Scan to see if any hidden codes. I know there are bulletins about this problem with Chevy, but can't find them.

By no way am I bashing Chevy. I have a 94 z71, 126,000 Miles, runs as good as new, 93 Suburban, 183,000, all problems with it were caused by previous owner(thought he was mechanic), once it was fixed by an actual mechanic, no complaints, had 86 Fiero(fireball), 90,000 miles, no problems, ran like a champ, sold for more than I bought the Lumina for!

[92 Lumina]

Transmision shifting is controlled by the computer. If the check engine light does not come on you may not store a "hard" code. You may need to have a mechanic run a diagnostic on it while you are having the problem. Intermitant problems are the worst.

Mark