I've bought a TH700 from a friend because the trans in my 92 is acting weird and slips from time to time. The trans from my friend is a 92 model like my own car. The trans has been rebuilt by himself a few years ago and he installed a TransGo shiftkit, corvette servo, .500 boost valve for the oil pump etc. He told me that the tranny was acting and shifting almost perfect, except for a hard 1-2 shift. I don't want that hard shift, so I disassemled the 1-2 accumulator today to look what spring and what piston is inside. This is somewhat of a black or dark grey spring and a metal piston. What would you guys recommend for a spring to install to shift smoother? I only use my car for cruising around on nice, warm days. No racing or autocross. The bore seems original. Here are a few pictures of the accumulator and the spring. Thanks guys!




This is how I removed the accumulator.

This spring was installed.


Separator plate.

Check ball location.

Feed hole.

 

If it has the TransGo Shift kit Junior or Senior (not the 700-2-3). Then the second accumulator springs from the Shift kit were not installed here. The TransGo second accumulator setup will be a blue spring installed first, in the accumulator housing, then the accumulator piston, then the Orange spring in last going against the separator plate.The setup you have here does not work well at all with the "B" 2nd accumulator valve and bushing in the valve body. The spring for this "B" valve must be very weak. It is the Black spring in the Shift kit. While it is down, check the 2nd gear feed on the separator plate. With a stock diameter 12" torque converter, the hole size should be .076" to a maximum of .086". If you drive pretty much aggressive, then .086" is okay. If you drive more conservative to moderate. Then .076" would be better for the part throttle shifts. With a 9.5" diameter torque converter, then .093" - .096" second gear feed hole on the separator plate. The 3rd gear feed should be .110" - .116" with a stock diameter 12" torque converter. And .135" - .155" with a 9.5" diameter torque converter.

 

Thank you for your answer. I talked to my buddy today who sold me the transmission. He installed a Transgo 700-2&3 kit. I haven't disassembled the valve body yet for measuring the 2nd gear feed hole. I don't have any spare parts from the shiftkit. If I have to change any springs or the separator plate, I will have to buy a new kit or single parts. Dumb question: What would happen, if I would just install the original yellow spring in the 1-2 accumulator that was in from the factory? I have a new one laying around for years, had a broken one years ago and ordered two. Seems to be much weaker by feel than the black/grey one that is installed now. Will this even work? I've been a mechanic for over ten years, but automatic transmissions are relatively new to me and I need to learn a lot about how they work and how all components work together.

Thanks.

 

If you are not going to take apart the valve body for now. Then install a real weak spring here for the time being. The 700-2-3 kit makes the is 1-2 hard shift happen. I add the TransGo Junior to this 700-2-3 to get the nice 1-2 part throttle shifts here. When you want to do this correctly, I can help with what you need here to make it right. Let me know.

 

Awesome! I can take apart the valve body, not really a problem, but then I'll need new gaskets. If you can tell me what I need to make it shift a bit softer, that would be absolutely great! I have my own workshop and tools, so that won't be a problem.