attn 700R4 experts

[Chris Demartini]

OK so I have a 700R4 in my new woods truck (88 wrangler TPI350/700R4/Atlas II/14ff/D60) with a TCI manual valvebody. I finally got a driveshaft from High Angle last week so I can get power to the wheels. I put the shaft in and lifted the truck off the ground to go through the gears. First is fine, 2nd is fine, but it locks up for a split second when I shift to 3rd. After that split second, everything is fine, and it goes into 4th fine. It does it while driving but its not as noticeable as it is on the lift.

What could be causing this?

 

[rjfguitar]

What do you mean "locks up?" Maybe it's just the converter locking or something.

 

[Chris Demartini]

like the ouput stops spinning

 

[jarheadk5]

Whoa... That's not healthy.
Sounds like a hydraulic problem; the tranny's trying to be in 2nd and 3rd at the same time. Might be an issue with the valvebody. It doesn't take much for the line pressure to go the wrong place at the wrong time and cause issues like this.
I'd call TCI and explain the situation, maybe they'll give you a new v/b to help isolate the problem.