200-4R won't stay in 4th

['75]

Hi all, I'm new to this forum, I usually hang out over at Corvette Forum, but I have a question for the 200-4R experts here.
I just rebuilt and installed the 200-4R from an 83 Cadillac Fleetwood int my 75 Corvette. I've got a couple of concerns, under heavy acceleration, I get nice high shift points, but at 120 mph, under acceleration, it keeps shifting back into 3rd. Can you guys give me an idea for the fix on this?
2nd concern is light acceleration from a stop, the 1-2 shift and 2-3 shift are mushy and can barely be felt and shift into 4th is at about 35 mph. For now I just run around town with the shifter in 3rd to eliminate the 4th gear and lock up which lugs the engine at around 1000 rpm. I have the tv cable adjusted so it is tight at WOT. i installed the Gil Younger shift kit, hardened stator supportand a kevlar band, but I can tell by the 2nd gear WOT shift that I will need to change up to a larger servo, that shift is kind of long and soft, no tire screeching on that one. I appreciate any help you can offer.

 

[chris718]

@ 120 mphour governor pressure and line should be the same as long as there are no leaks in the circuit,@ wot the tv plunger will send 90 psi of oil out of its drilled detent hole into the tv downshift circuit and if the pressure in combination with the valve land diameter of the 3.4 tv upshift valve available is greater than the opposing governor pressure acting on the 3/4 shift valve diameter the trans will dump the overdrive 4th clutch oil back into the pan thru the exhaust hole on the bottom of the valve body and put the trans in high gear direct drive.

 

['75]

Thank you for the help, can I lower the 4th gear shift at high speeds without affecting the 1-2-3 wot shift points? I'm guessing if I slack off on the tv cable adjustment, I will have lower shift points throughout. I would also like to have the 4th gear shift under light acceleration higher. My trans code is 3AA

 

['75]

ttt

 

['75]

I cannot post pics till after 4 posts.

 

['75]

Here are pics of my TV cable hook up, it travels 1.22" from idle to WOT.

 

[chris718]

If you want 4th later under light throttle use a heavier shift valve spring and install a heavier primary weight on the governor.You are trying to do 2 things that contradict themselves.Not that this isnt good but 1 may have a negative effect on the other.My advice should get you close,however you may need to change the 3/4 shift valve as well.If you send me your governor and shift valve setup(3/4).I can probably come up with something.