Could a rebuild with GN seperator plate cause late 1-2 shift??

[RA3Goat]

Just had trans rebuilt after breaking foward drum, replaced with CK billet. Trans always had very hard 1-2 shift, and it would stay in first until about 20mph, maybe a little less. It was recommended I install stock GN seperator plate, to start with clean slate and decide if I want it to shift harder. Trans is behind Pontiac 400", 450 horse, ProTorque non-lu converter 2800 stall (car starts moving at idle). Now it seems the trans shifts later at part throttle, and softer. I used to be able to make it shift to 2nd by lifting, but now it still stays in first. Seems to go to third fine. TV cable has not been moved. Previous seperator plate had several holes drilled over and one hole blocked, I will try to take pics and reference CK manual later. Any thoughts would be appreciated. Thanks.

 

[chris718]

the seperator plate cannot cause such a problem.there is another thing going on here.try adjusting the tv cable and checking psi .this is the first step in diagnosing a problem.need a gage?call in

 

[RA3Goat]

Sorry in advance for the long post, but I hope someone can help.
I checked pressure readings. Pulled cable towards radiator to shift slightly earlier, this slightly decreased pressure, so I readjusted cable following the steps in CK manual, then recorded pressures. please see below.
Gear PSI at Min TV PSI at Max TV
Park 85 275
Reverse 130 275
Neutral 85 275
D4 85 275
D3 85 275
D2 125 150 (seems low)
D1 125 150 (seems low)

Attached is a picture of the modified spacer plate previously in the trans, when it shifted harshly into second at part throttle, all the time. also attached is an illustration of the spacer plate from the service manual, for reference.
I measured the diameters of the holes recommended to be drilled in the CK manual, refferred to as 8, 14, 18, and 28. Hole 14 was 0.081". Holes 8, 18, and 28 were 0.106". All of which are smaller than the limit recommended by the CK manual. I do not know how these diameters compare to a stock GN spacer plate, which is currently in the trans. Would these holes affect the line pressure??
Also, one hole, near #5, appears to have been filled in the modified plate. What would this affect?
The oil feed hole in the 1-2 accumulator was also restricted and I believe there was no spring.
I just want to make sure this trans lasts and doesn't kill itself, but I do want frim shifts.
Thanks all.

 

[RA3Goat]

low D1, D2 pressure

anybody?

 

[chris718]

are all the shifts late or just the 1/2?if you disconnect the tv cable and drive easy what happens?if you want assistance answer these two qs before we can go further.sounds like the rev int boost valve is in backwards.

 

[RA3Goat]

Chris, thanks for the reply. The shift to 3rd does not feel to be late. I disconnected the TV cable and with leaving it in drive, it pulled ok in 1st, shifted to 2nd, then would just rev. I think it shifted to 3rd. I couldn't get over 20mph. Even putting it in D2, the motor would rev, but no acceleration.
I don't imagine anything was done to the pump or boost valve when the foward drum and spacer plate were replaced, but it drove ok before. Thanks again for the help.
Dan

 

[WE4]

Ck to make sure

your vb and case are not earlier than 84. If you have a lock up valve train in the valvebody and you added a late plate, (one for a VB after 84 that has a bore plug in it) it is a possibility that would happen. the late plates had the lock up feed hole closer to the 1-2 ck ball in the vb. The eatly ones had the feed hole lower to feed the valvetrain in the lock up ore.

Bruce
WE4
www.PTSXTREME.com

 

[RA3Goat]

Bruce, I do not know what year the vb and case are from. The trans was set up for non-lu when I purchased it several years ago, and have been running the same converter since. So potentially I installed a late plate in an early vb and case? I attached a picture of the original plate in a previous post. Can you tell from the picture if the plate is early or late? It did have one hole closed off. I assume that since the stock GN plate that was recently installed, was recently purchased, that it is likely of the later style. Should I just reinstall the original plate and see what happens? or should the line pressure be higher in 1 and 2, no matter what plate is installed?
Thanks, Dan.

 

[77 cruiser]

I don't think it should matter on the press. it should be higher in D1 & D2. Have you check your intermediate boost valve? The transfer pipe could be leaking where it goes into the VB also.

 

[RA3Goat]

No, I have not checked the intermediate boost valve or the transfer pipe. Would these only effect pressure in D1 and D2? Pressure is constant and does not seem to fluctuate.