I bought the car two years ago, 87 iroc camaro TH-700r4 automatic....it worked fine until about 8 months ago. I was driving down the high way and it just let go of 3rd and 4th gear and started doing what i describe below. Now i am trying to fix it before i rebuild it or buy a rebuilt one. First of all i adjusted both cables that the Haynes manual said to check. But didn't change anything. Also there are no weird noises.
Okay I put it in to over drive and it feels like i get 1st and 2nd and at about 2500 rpm (between 25-30mph i believe) it lets go and revs and i have to stop before the trans goes back in gear where it starts in first again.
If i put it an drive or 2 it does the exact same thing.
But when i put it in 1 i seem to get maybe first and third? Well it starts out in first as normal but then when it changes I get a lower rpm acceleration than OD D and 2 did when they changed. This leads me to believe it is going directly into third. It holds that gear and dosn't let it go.
This seems odd because i thought the low gear (1) only gets 1st gear.

Well i checked the fluid level it was fine and the fluid was still clean with a slight brown tint to it as most cars, it also smelled normal. I talked to my Auto tech teacher and he told me that it could be the seals on the valves, he said i could add some brake fluid and that will swell the seals. I added some and felt no difference whats so ever.

Before I go and spend a grand on something new could this only be a computer problem?
Or maybe the fluid pickup? (pans not dented tho)? Something i can fix? I was trying to avoid pulling it, but if it is absolutely necessary i will.

Thank you anyone that can offer any help.

 

Anyone want to help?

 

There no way its the ecm doing that. Sounds like its time for an overhaul.

 

This is just my opinion... but here I go. MY transmission did this almost exact same thing. i would go through the gearing and if the transmission was cold... i could do around forty in o/d without blowing the engine. but if the tranny was warm then i would have to play with the shifter and sometimes forty was attainable... but most of the time i would have to limp home at around 22-25. i ended up putting in a jasper crate 700r4. my life has been bliss!!!