350 turbo drops out of 3rd gear

[Ratt643]

Hey Guys,
I rebuilt a 350 turbo a few days ago. Put in new Raybestos clutches and steels, Fairbanks shift kit, new gaskets and seals. It shifts great all the way through the gears. when it hits 3rd, it does fine until you let off the throttle, it drops out of gear. as soon as you rev the engine, it goes back into gear. it will also start slipping at hwy speed. i took it back out and tore it down. No nicked seals and sealing rings on pump were not damaged. The forward clutches were burnt. I have read that this could be a governor issue or maybe the pump may be worn out aroung the sealing rings. Could this be a bad case or a valve body issue. one post I read suggested that the case where the governor goes in could be worn causing fluid pressure to bypass the governor. Any help would be appreciated but I am about ready to start all over with another tranny. Thanks in advance!

[MagicRat]

Did you check the line pressure before you pulled it out?

It's been a while since I've been in a 350. My rebuild manual makes a big issue about needing a pristine 2-3 accumulator piston and Teflon seal. If its damaged or worn in any way, the book calls for an all-new piston and seal.
Obviously if this piston had a big leak, it might explain the performance you are getting.

Just my 2 cents.

[j cAT]

Originally Posted by Ratt643

Hey Guys,
I rebuilt a 350 turbo a few days ago. Put in new Raybestos clutches and steels, Fairbanks shift kit, new gaskets and seals. It shifts great all the way through the gears. when it hits 3rd, it does fine until you let off the throttle, it drops out of gear. as soon as you rev the engine, it goes back into gear. it will also start slipping at hwy speed. i took it back out and tore it down. No nicked seals and sealing rings on pump were not damaged. The forward clutches were burnt. I have read that this could be a governor issue or maybe the pump may be worn out aroung the sealing rings. Could this be a bad case or a valve body issue. one post I read suggested that the case where the governor goes in could be worn causing fluid pressure to bypass the governor. Any help would be appreciated but I am about ready to start all over with another tranny. Thanks in advance!

check that the vacuum line is correct and not leaking. also the detent cable is adjusted correctly and you have the correct cable.

valve body gasket / plate. 2-3 shift valve. clutch seal rings . direct clutch assy. check for proper install and condition


when checking line pressure disconnect the vacuum pipe.