I have an 89 formula 305 TPI 700r4 tranny. When I first start the car in the morning and drive it, it shifts perfect, the shift points are right on and the shifts are firm. After 15 or 20 minutes of driving the car starts to lug and shift early into 3rd and 4th. (It will also do it almost every time i get on it). Also when it acts up it will shift from 3rd to overdrive (at 36 mph wtf!) the rpms drop to 900 then tranny feels like its straining.with my foot steady on the gas and it shifts into 3rd it will downshift then shift (like it doesnt no what gear to be in). I've adjusted the TV CABLE thats not the problem because it shifts perfect when its cold. The strange thing is it will do it one day and not again for three days. could it be a sensor? which one? Has any body heard of anything like this. Open for any suggestions! Thanx

 

Don't know the answer but if you don't have a tranny cooler on there, get one! A tiny $30 investment will make that 700r4 last twice as long--and that is no word of a lie

 

The torque converter is locking up (to soon) for some strange reason, disconnect the electrical plug from the drivers side of the transmission, & repeat the same driving conditions, and see what happens?

 

Forgot to mention I changed the TCC switch two months ago.

 

Oh yeah, got a link?

 

Many parts stores sell trans coolers for between $30-$40. Lots of online places too. If you can't find one, I can get you a Hayden 5" x 12.5" x 3/4" cooler for $30 plus shipping.

 

Yeah, no need to order one in. You neighbourhood parts store will have one. 12,000 lbs. GVW will work just fine and they're only about $30.

I just can't believe how many folks don't know this. It will save you a fortune because those 700r4s cost a lot of money to repair