This is a strange issue. My 86 700R4, which has been upgraded with the 10 vane pump, hardened sun shell, new sun gear, new planetaries, fresh rebuild kit, and a transgo shift kit is dead. It worked great until a few months ago when I lost overdrive. I parked the car and checked all the vitals. I drove it a few weeks later and it wouldn't shift past 2nd gear. I rechecked the fluid and re-adjusted the TV cable. While test driving, I lost all the gears. In order to get the car back home, I had to turn the car off then turn it back on and it would move. I had to keep doing this several times to get out of traffic and back to my house. Is this an internal seal leaking down or a bad converter or pump?

 

Your first complaint about losing 4th and then 3rd is the 3-4 clutches.

Your no move condition may be a clogged filter. A pump or converter won't usually act like you're explaining.

Regardless, the 3-4's being wasted makes it time for a rebuild. Your "no move" problem should be easy to figure out when it comes apart.

Frank
CPT

 

Aggree with above the filter is clogged with debis from something that failed . You only can move a little way after turning it off because of the backwash semi cleans the filter out , You are definatly going back into it