Ok so my 91 Ta shifts fine from a dead stop to 4th gear but its when im in town where I have some problems. If I am not below 20 miles per hour and I push the accelerator, the transmission shifts into 3rd gear for like one second and then immediately shifts to 4th and my rpms drop to 950. So to combat the problem, I have been just driving in second gear while in town. Any ideas on what this would be? My guess would be towards the torque converter.

-Transmission fluid changed and helped a little about 1,000 miles ago. I also adjusted the shift linkage (the one by the throttle cable). It drives just fine but It just bothers me not knowing what would cause that. 74,000 miles on car. Odd thing is that when I first pull out of the driveway, It will shift perfectly just at the right rpms from 3rd to 4th, but it only does it once before it starts shifting funny. If it is the torque converter, what kind of money are we talking and have to pull tranny to replace it?

(sorry I didnt get a response from the transmission thread so I thought id try it here)

Thanks guys!

 

If it's dropping your rpm to 950, then it's the TCC locking. Just shifting from 3rd to 4th at a low speed would cause barely any drop in rpm if the TC were unlocked.
My 86 does the same thing with the L69 chip in it, if I'm not into the throttle hard enough; locks the TCC immediaely upon shifting to 4th gear. With the stock LG4 chip, it didn't lock it that soon.
I don't think it's a TC problem. I'm not familiar with the sensors and logic on your 91, but it's something erroneously telling the TCC to lock. Does your car have a TPS?

 

my 91 does the same thing but can go as low at 800rpm. been doing it for 60,000miles already. it did it with the original tbi motor and then with this tpi motor. i read somewhere it has something to do with a spring in the valvebody. short spring syndrome? it just gets me great gas mileage so i let it go.

 

By TPS do you mean tuned port? If thats the case then yes. Haha sorry I am unfarmillar with some of this stuff.

 

Firebirdluver, that is great to hear that you expierence the same thing. I had a mechanic tell me that it was supposed to shift like that (but I didn't believe him) It doesn't seem like I should be driving 25-30mph in 4th gear. It is still puzzling why It shifts differently upon first driving (during the first shift) but oh well...hahah

I dont have a problem with it shifting early but I didn't know if driving at 800-950 rpms would be hard on the engine/transmission?

It is a relief to know that you have the same thing. I doubt that it could be just a "coincidence".

 

TPS = Throttle Position Sensor. If that's misadjusted or not giving the ECM the right signal, it could be the reason for the abnormally early TCC lockup.

 

Mine will skip 2nd sometimes. Then other times won't go into OD until it's at operating temp. And Then... Occasionally there is a popping sound when accelerating from a stop while turning right you can feel on the shifter. I figure she's 21... she'll do what she wants.

Someone said it could be the governor assembly that is behind a round cover on the driver's side, tailshaft area of the tranny.

 

Ok. So Is there an easy way to figure out if the TPS is bad? And you think that could be the cause of the early shift?