CHEV VAN

I have a TH350c which had a master overhaul kit. Which had 1 mok,1torque converter tc ,1pump assy pa, 1 forward drum fd, 12 qts. fluids atf, 1 filter all done on 01-13-2010. The same day I pick the van up it want go into 3rd gear unless you first go to neutral and back to dr. then it go into 3rd. When you check the fluid lever, it be the same as with the engine running or not the fliud lever be the same about 3in past full.
now that reading also the same after driving it over 20 minutes. I brought this to they attention they said that ok for the fluid lever to be over, and for not going into 3rd gear you just need a tune up. Its still doing the same thing now 01-23-2010 That all... I NEED SOME REAL EXPERT HELP IN THIS MATTER. Its a 1981 . THANKS

Limey

I am not an expert when it come's to transmission's BUT it say's do not over fill for a reason. I would drain some of that fluid and hope it didnt damage the new build.............and then see if you still have the prob's