200r stage II , riddle me this ...no wot upshift

[gn4u2c]

ok so what I can verify by case is its a 85 GN trans, was done as a stage II rebuild (unknown builder came with a 1/2 assembled car I bought long ago) there is a list that says billet drum, harded input/output, HD clutches and steels, billet anchor, new valve body, shift kit (no brand listed), out of box newly redone D5 from ATI, just now getting installed and used in a monte carlo with a mild 400hp ish 383 with a 3.42 GN rear out back. lockup correctly installed, new GM tv cable, swing correction brackets used on holley linkage. Castrol dex/mec atf) 1/2 qt over full,defiantly a new trans, plugs in it all sealed up tight blah blah defiantly new redone.
install it correctly fill converter first, and trans, adjust tv and all prior to startup.

Now drive it and at light throttle it seems to shift ok maybe a touch early lock working and so on. under WOT it will not shift not 1-2 2-3 3-4 just hangs in gear. let up to about 3/4 it will upshift and hold power fine no slippage I can feel. dropped pan spotless. before I start swapping gov springs (not falling out) boost valves or anything else. I buttoned it back up and did pressure check. results below used a quality Mac test kit.

idle fully relaxed cable p 100, r 155, n 100, od 100, d 100, 2 225, 1 205
idle fully tight cable p 235, r 260, n 265, od 260, d 255 , 2 255, 1 260 but jumps between 240-280 rapidly
1500 rpm tight cable p 280, r 280, n275, od 275, d 280, 2 255, 1 255 but jumps between 250-260 rapidly

I have built a ton of engines and several old 350/400 turbos just no 200r units. I feel like this is most likely a valve body or governor combination problem. I have no problems pulling them and making changes but with so much conflicting information out there not exactly sure where to start.
for reference I check pressures on my built 200r in the 87T and came up with 290 ish but rock steady . my old GM manual shows anything over 250 as excellent but that's for a trans/ stock car.

thanks guys all information appreciated.

 

[mikestertwo]

Wrong valve body/governor/or bad T.V. cable geometry.

 

[TexasT]

Drop the pan and see if wot is pulling the tv all the way out.
Look at the vb for the factory paint marking if it didn't get washed off. If is doesn't have bq it could have been washed off. If it has something else then we know what it is.



It might look something like this.

 

[gn4u2c]

tv geometry is correct, used the correction kit and compared it to my t type dead on.

governor appears to be the original 85 buick unit. no the valve body has a pink marker stripe on it. otherwise unknown to me , don't see any stamping or numbers on it.

 

[gn4u2c]

I will pull the pan back off later today and verify full pull of tv. it does get (tight) right at full throttle at linkage. like tight guitar string tight. I will also give a serious close inspection for any markings on vb other than the marker stripe I remember

 

[TexasT]

If it is real old, someone might have put an old transgo kit in it. Those weren't known for their being good. Sadly it involved drilling and can't be easily backed out.

Might have to drop the vb. Might have some sticky valves in it from sitting.

 

[gn4u2c]

Yeah just weird it does ok just light driving so it would seem valves are free. It's going back out tonight after work
Is done for day.

 

[TexasT]

How many miles have you put on it? I know when I put the one in my car together it took more than a few trips around the block to get it going and shifting well.

 

[bison]

Pull governor and use a medium governor weight where the light one was. Don't change the spring. You need to achieve a wot shift to get a baseline.


Sent from my iPhone using Tapatalk

 

[gn4u2c]

Put about 60 miles on it. Thanks Bison that's what I was looking for I give it a try today