When I shift my 1984 700R4 trans manually, the shift between 2nd and 3rd is always nice and hard below 6000 RPM. When I go above that, sometimes it shifts hard, other times it slips. Sometimes it slips very mildly, sometimes very harshly, sending my motor to it's 7000 RPM rev limiter. What could be causing this?? What do I need to do?? Thanks in advance.

 

The input drum has a checkball that can unseat when there is not a enough volume of oil to bring on the 3-4 clutch pack (common). The Trans-Go Performance Shift kit will fix this in most cases, as it triples the volume of oil.

 

Be careful using a shift kit to solve the problem. I did that and my 2-3 got worse and everntually slipped all the time. Sometimes a drop in fluid preassure can cause the same slipping problem or worn clutch pack. Even yet, check your kick down cable and be sure it is adjusted properly. Mine used to slip at only 5,000 or above, then it got worse as time went on.