Th350

[quadsheavn]

I have a turbo 350 trans, that will not shift at WOT. It shifts fine at light to moderate throttle. We have changed the modulator, governor, and adjusted kick down cable. Trans fluid is fine and at correct level. Specs of the truck and trans are below:

'83 Chevrolet C10
Goodwrench 350 50K mi. small cam. 750 double pumper.
3000 stall(Holeshot I think) TH350 no shift kit. HD Bands, clutches, ect.
3.73 open diff

Transmission has less then 5000 mi on rebuild. Do not know when it started "not shifting". It has sat for 2 years, driven on and off occ. What is weird is it shifts fine at anything below full throttle.

Thanks for any help or insight y'all moght be able to give to me.

Melissa

[badfast]

I have kinda the same problem with my 92 chevy p/u with a 700r4 trans but it acts like it go's into neutral at around 90 at wot and no one has really been able to help me. so good luck hope you get it figured out

[Brianlp]

Melissa,

I have a 73 suburban with the opposite problem. The tranny is a crate unit I installed a few years ago. The tranny performs flawlessly in all conditions other than at WOT. AT WOT it shifts too early (opposite of your issue). The engine has plenty of power up to ~5500 RPM, but most WOT shifts hit at ~3500 RPM. This is a bummer because it is a 4WD with 3.08 gears for freeway mileage.

I'd like to figure out what I can do to change the WOT shift points (1-2 and 2-3) without affecting the part throttle shift points, detent and other factors. The detent cable and detent performance is fine also. I've also checked out the modulator and the fuild is clean (only about 20k miles on the tranny anyway).

Please let me know what you found out (or someone else). I'm pretty sure we have the same root cause with different failure modes.

-Brian

[randy78]

check governer or pull the cable tighter by adjusting it at intake manifold bracket

tranny wont shift at WOT anyways, it will wait til you reduce from WOT
dont push pedal down so far and then it will shift

[Brianlp]

I've checked the detent cable and it is tight at WOT (as it should be); this is not the problem. Does anyone out there have any experience with the governor or customizing the TH350 shift points? Valve body modifications? Especially at WOT?

[randy78]

if cable is too tight then it will pull out all way before accelerator can be open all the way, thats why you hold accelerator all way open by hand at carb adnthen pull cable housing back and then let go of the housing lockbutton