'97 Z71: No shift at WOT

[jimbaeumel]

Been reading a lot of the sticky post, but haven't seen anything that is dead on as far as describing my symptoms.

No gear will shift out at WOT. I have had the transmissino serviced. Shifts are good under regular driving. Down Shifts are clean.

Should I start with checking the TPS? After that where should I go?

Thanks in Advance.

 

[Axewhlder]

I'm having a similar issue. I just changed my TPS today as a matter of fact. Under light throttle it up/downshifts fine. If I give it half it will downshift. If I put it to the floor it pauses and then sometimes it will drop a gear but it's rare. Don't know if you have to unhook the battery after you change the TPS or not but even after changing it I didn't see a difference.

 

[JonZ71]

check fluid level.

 

[jimbaeumel]

check fluid level.

Fluid level is fine. I'll test the TPS sometime this week. Its a High Mileage truck no telling if when the Transmission has been rebuilt replaced.

 

[JonZ71]

Sounds like the TC is slipping horribly, as in low in fluid. my camaro did this, just banged off the limter, kept driving checked fluid, top off drive more until no more.

 

[jimbaeumel]

Something else i thought of. My Speedometer will stick sometimes, then picks back up. Maybe the VSS? I figure this weekend i'll clean the MAF, Test the TPS and replace if needed, and if neither of those help I'll replace the VSS. I'll update everyone after I run through all the testing.

 

[JonZ71]

uhhh yeah if the vss isn't reading, it won't shift.

 

[jimbaeumel]

uhhh yeah if the vss isn't reading, it won't shift.

Thanks for your help. I used to go to deland every summer for Stetson baseball camp back when i was in school. Nice place down there.

 

[JonZ71]

Meh, it sucks now. It's nice not being in orlando anymore, but just boring town.

 

[jimbaeumel]

UPDATE: So I havent tested anything, but driving the truck today i realized that my speedo problem isnt as random as i thought. When i drop down in to passing gear the speedo freezes until i lett off the gas. When right before the speedo picks back up and the tranny shifts at the same time. Makes me think the VSS could be the culprit. Now I have read there is a gear that the VSS gets its reading from and it can also go bad. Could someone explain how that works and how often that gear actually needs replacing?