I am here to TESTIFY with brother D...can I get an AMEN?
Installed the TransGo kit yesterday along with a bottle of Lucas and a new filter. What a difference! Shifts are quick and firm. I can run it at WOT from a standing start and it hits every gear right when it's supposed to, no slipping. Drops nicely into 4th at about 85mph.
The TransGo kit itself is easy enough to install, but it's clearly marketed to professional trans techs, not the DIY guy. For example, the kit includes the scotch brite pad, but nowhere in the instructions does it say to scuff the accumulator bores. The kit includes new seals for the accumulator pistons but doesn't tell you that's what they are for. The kit also includes a few additional parts and seals to address known wear points on the 4T65E but I think the trans has to come out or at least more apart than just the pan to get to them. Fortunately there are a couple of good write ups on the web, even though they were for different brand shift kits.
The basics of the process are removing the accumulator assembly form the bottom of the trans, then taking the cover off it on the bench and opening up the piston/bore assembly. With the TransGo kit, you basically replace the factory springs inside the accumulator with color coded ones that come with the kit, and add a couple spacers that slide on the actuator rods. Put it back together and re-install, if you can turn a wrench this is an easy job.
One problem that I do have is a shudder at 75 mph...only happens after you've been on the highway for a few minutes, and only when you are accelerating. Back off the throttle and she is smooth as glass. If I manually shift down into 3 the symptoms are identical so I don't think it's trans related, maybe an axle? Any tips on what else I can do to narrow it down?
