700r4 won't upshift into drive WOT

[trbo668bird]

I built a 700r4 for a good friends 71 GS last year, it shifts great most of the time but sometimes it will not go into drive unless you let totally out of the throttle and get back into it (sometimes it takes two or three times). This problem seems to get worse when hot. He put a supercharger on the 455 and now that we're getting the tuning closer the trans is getting worse.
Changing the governor weights hasn't helped, installed a new TCI valve body and that didn't help either.
Help, I know I should have built a 200 instead but.......

 

[ITSAV6]

700

Most 700's won't full throttle OD.

 

[chris718]

YOU HAVE A MISMATCHED VALVE BODY AND GOVERNOR ASSEMBLY THAT WONT WORK WITH THE POWER CURVE OR FINAL DRIVE RATIO OF THIS VEHICLE .FIND AN IROC VBODY FROM AN HO WITH A 3.73 REAR AND THIS WILL GET THINGS GOING IN THE RIGHT DIRECTION,STILL MAY NEED MINOR TWEAKING BUT IT WILL WORK.ALSO S10 WITH 3.42 WILL WORK.MAKE SURE TV PULL RATIO IS CORRECT FOR LOW SPEED OPERATION.OR YOUR V BODYU IS JUNK BUT IM SURE YOUVE CHECKED IT ALREADY.HAVENT YOU?

 

[trbo668bird]

The trans core was from a 90 full size truck, I reused the original valve body and later swapped in the TCI valvebody that has the same calibration as a HO Camaro. The new valve body raised the shift points up to where they need to be but I still have the intermittent WOT into 3rd gear problem. I've tried different gov weights and spring combinations but nothing seems to help.

 

[chris718]

AREV YOU SAYING BOTH VALVE BODIES ARE PRODUCING THE SAME EXACT PROBLEM?

 

[trbo668bird]

yes, trans will not shift into 3rd with either valve body

 

[chris718]

SOUNDS LIKE A CROSSLEAK IN THE THIRD CIRCUIT OR A PROBLEM IN THE 3RD CLUTCH APPLY CIRCUIT.IF YOU INSTALL A PRESSURE GAGE WHAT ARE THE NUMBERS?

 

[ITSAV6]

my bad

Thought it was no full throttle OD! My bad! Tech on Chris

 

[chris718]

heres the remedy and its cheap.block the part throttle detent hole in the seperator plate and tell me how it works.

 

[lost2a6]

I had this same problem in a 700 that I had and what I discovered was that I had forgot to install the little screen assem. in the pump. Why me leaving the screen out would keep it from shifting I don't know. I Put it back in and it worked fine.
Steve

 

[trbo668bird]

Thank you Chris, I'll try to get the car up in the air this weekend and try blocking the detent hole as you suggest. Hopefully I can fix it that simply before we grenade the motor. Bad thing is as soon as I get this car tuned in and get it to hook up it's going to grenade the input shaft and or drum, he wasn't planning on making this kind of power when I built this trans. Think a 700r can hold 600 horsepower? me neither
here's some pictures of the car
http://www.v8buick.com/showthread.php?threadid=20860

 

[chris718]

ive got you covered on the drum and shaft.

 

[nirto71455]

Hi Guys,

First off, Thanks Chad for getting this issue started. And thanks Chris for your help.

The issue with the trany is this. If I leave the car in drive and mat it, it will "always" sift from 2nd to 3rd under WOT. it typically does this at about 5200 to 5300.

However, if I manually shift the car under WOT, it will not shift from 2nd to 3rd ever without having to get out of the trottle. 1st to 2nd shift right when I tell it too, but 2nd to 3rd hangs every time. It doesn't matter what weights or springs are on the gov.

Chris, do you still tend to believe this is being caused by the detent hole your talking about? If so, could you describe where it's located and possibly what it will take for Chad and I to plug it?

Thanks again for your help.

Rich

 

[nirto71455]

Anyone????

 

[chris718]

when it doesnt go in to 3rd what happens if you dont let off and make the mph go up?does it shift or redline?2/3 shift valve or spring malfunction.

 

[nirto71455]

Originally posted by chris718
when it doesnt go in to 3rd what happens if you dont let off and make the mph go up?does it shift or redline?2/3 shift valve or spring malfunction.

Hey Chris,

When it's manualy shifted from 2 to 3rd under full throttle, it will just sit and bounce off the rev limiter at 6000rpm until you let out. Since it's missing, MPH is actually falling off at this point. However, when the tranny shifts it's self (left in drive) it will shift from 2nd to 3rd under full throttle every time at about 5200 to 5300rpm.

Thanks for your reply.

Rich

 

[chris718]

what rpm are you shifting manually to 3rd?

 

[nirto71455]

I can put in 3rd manually just as soon as it's shifts into second and it will hang onto second gear............ It doesn't matter what RPM is't sifted at (short shifed or not) it still hits the rev limiter at 6000 until you get out of it.

 

[chris718]

try blocking the governor weights wide open and manually shift it .post results .dont take off in any range exept manual lo and then do your upshifts.

 

[nirto71455]

Ok....... I'll give that a shot and let you know.