New 700R4 Won't shift into 3rd at WOT

[Michael Bennett]

What type of throttle valve cable are you using?

It's an adjustable for length and the end that attaches to the carb is adjustable as well. The cable sheath adjuster is tight so it doesn't lose adjustment and so is the carb end. It's all set up right to the best of my knowledge. I've had the car at the trans shop and he says I have the cable and all the adjustments right.

 

[84cutspreme]

The governor is a stock one, not sure what it was out of but but it had pretty light inner weights, it was allowing 6000 rpm 1-2 shift. I changed one inner weight to a slightly heavier one off another facotory governor I had and it reduced the WOT 1-2 shift to 5200rpm. With the cable at full pull, no 2-3 shift. With 1/4" slack 2-3 happened at around the same but shifts were soft and part throttle shifts too early.

Not sure about switche, but I do know that with the TCI lockup kit they installed the converter only locks up in 4th gear.

Next time I talk to the guy I will ask him about the front pump rotor and how many vanes, that is a good point.

It's supposed to have a corvette servo in it.

I would pull servo with trans in car, inspect seals. They can easily be torn while installing. also another quick test is to put a pressure gauge on trans and see what internal pressures are doing. Soundslike either losing pressure from a leak at servo or not enough pressure which may be front pump if 13-vane not installed

 

[Michael Bennett]

Talked to the trans shop today. He called his contact at TCI and they told him the same thing that 700R4's will not upshift into 3rd under WOT automatically. He said he then talked to an old contact who worked for hydramatic and told him the same thing. He did say if you shift manually it will shift into 3rd under WOT. I'm going to try that out. In the mean time, I'm going to check with some other transmission shops to see what they have to say.

 

[pontiacgp]

is that a powerglide hybrid...a powerglide under wot and a 700r4 for normal cruising......

 

[Michael Bennett]

Picked up a line pressure gauge today and did some testing. With the TV connected and adjusted properly, I have what would seem to be good line pressure in all gears. All over 180 and up. Where I have a concern is that when I drive the car and go to WOT the pressure drops to 150 initially and then to 120 at about 4500 rpm and stays there until I get out of the throttle. 120psi over 4500 rpm seems like an issue to me, but the only info I can find on the internet about checking pressures is all at lower rpms.

 

[pontiacgp]

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Upgrading to an overdrive transmission is an easy and worthwhile improvement. Find out how easy it really is with help from TCI Auto.

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[84cutspreme]

Upgrading To A 700R4 Overdrive Transmission With TCI Auto

Upgrading to an overdrive transmission is an easy and worthwhile improvement. Find out how easy it really is with help from TCI Auto.

www.rodauthority.com

This is procedure in my transmission manual for pressure testing

Also checked operations manual.
States that in automatic 3rd the band is not applied, forward clutch applied, 3-4 clutch applied and forward input sprag.
States in Manual 3rd no band applied, forward clutch applied, overrun clutch applied and 3-4 clutch applied. seems the only difference between auto 3rd vs manual shift is the forward sprag in auto vs the overrun clutch in manual.

 

[Michael Bennett]

My line pressures all seem fine with the tests that I have found, but no one talks about WOT actually running through the gears. I've got to think that 120psi isn't enough? Can anyone confirm?

 

[pontiacgp]

My line pressures all seem fine with the tests that I have found, but no one talks about WOT actually running through the gears. I've got to think that 120psi isn't enough? Can anyone confirm?

did you read the articles that were posted?...