very hard shifts

[marsgmc]

did my own rebuild based on the project by hyrule....
after 1200 miles the trans started shifting very hard, my diagnosis is the tv boost valve is stuck and causing high line pressure. God i dont want to pull this thing out again.
BTW i am a Master Certified Auto Technician for 20+ years this was no garage floor rebuild and everything was cleaned in a hot pressure washer unit. so what the !#*K
did some clutch break loose and jam it up?
Has anyone experienced this before?

 

[5SpdTy]

Re: very hard shifts

not sure bout the tranny problem but have to comment on ur sig. i did the same thing. 100k at 100mph. i felt like i had to do it. i was acually passing the first 2005 corvette i saw on the road. felt great. so props to u. ok back to tranny talk

 

[myclone]

Re: very hard shifts

my diagnosis is the tv boost valve is stuck and causing high line pressure. God i dont want to pull this thing out again.

You can pull the TV valve out without yanking the trans. Just drop the pan, loosen the tv actuator assembly, take out one roll pin and it will slide out.

Try starting the truck, leave it in park, disconnect the tv cable at the throttle body, and give the tv cable a few yanks real quick. It might break loose without having to crawl under the truck at all (disclaimer: it hasnt worked for me so far but Ive heard of it working for other ppl).

 

[jwaller]

Re: very hard shifts

you can buy a pressure gauge and tap into the pressure port on the drivers side(above the propshaft). check for proper line rise via TV cable movement. if you dont have line rise(pressure is always high) the TV valve is stuck.

like dave said you can yank the tv valve without R&R the trans.

 

[marsgmc]

Re: very hard shifts

thanks, already got the guage just procrastinating on doing the deed. hey its winter time and its not being driven anyways.I've got time.

 

[chris718]

Re: very hard shifts

a tv limit valve that doesnt exhaust can also cause this.it is fed oil directly from the pump making it easy to stick.if the plunger is fed over 90 psi it will feed too much pressure into the tv upshift circuit that delays shifts against governer upshift force as well as raising line pressure.without the gage hooked up you can check for stuck boost by pulling the cable out all the way.there should be a groan produced by the pump as well as a slight drop in engine rpm.gage test will immediately isolate the circuit in question