Tranny Issue

[KansasGN]

I just bought an 87 GN, tranny seems to work fine under normal driving conditions. I was told tranny has been built, so I really have no idea on the internals. I do know has a manual trans brake, deep pan with temp gauge, Pro Edge Converter, fluid looks good. So when you launch the car it leaves hard then acts like it jumps out of gear, let off and then apply power and tranny acts fine. I have check converter depth and it is correct. Any help greatly appreciated. Thank you

 

[mikestertwo]

What gear is it in when it "jumps out of gear"? What is the fluid level? Try overfilling it by 1 quart and see if it still does it.

 

[KansasGN]

What gear is it in when it "jumps out of gear"? What is the fluid level? Try overfilling it by 1 quart and see if it still does it.

It has happened in 2nd twice, and I haven't done it anymore, concerned I was going to trash something. 1st gear is the manual transbrake. Fluid level is spot on according to dipstick but it could be off, good thought. Has a deep Hughes pan and was told has a 700r4 filter. I just bought it about 3 weeks ago, so not sure what I have really. I will try adding more fluid and see how it acts. Thank you!

 

[INEEDAGN]

Where you at in Kansas? I may be able to take a look.