I rebuilt my 700 over the winter and performed about a dozen upgrades to it. When I drive around normally the car shifts great and has a nice feel to it. It seems that when I beat on it on the highway it slips on the full throttle 4th-2nd downshifts. (Usually passing slow traffic or on the on-ramp) It will seem to slip for a bit then finally fully engage in about 3 sec. or so. It seems to down shift from 4th to 3rd without any problems, however the 4-3 shift takes place before wot so I think it might just have to do wot down shifting. What gives? Is it a TV issue? Fluid level is good. I am pretty sure the TV cable is adjusted correctly.

 

How much hp is your motor giving the trans? I went from an anemic 170HP 305TBI to a 355HP ZZ4 engine and my tranny slips whenever it shifts at more than 1/2 throttle.

Maybe your clutches and servo aren't strong enough to hold your hp.

 

My trans is built to hold the HP, besides I am running a pretty much stock 305. The car has been put up all winter, I will try messing around with it in the spring.