Transmission Rebuilding 101

Be very careful what you read. Very few, if any, parts interchange between the 904 & 727. The only exception that I know of is the valve body-BUT it must be the same year. Got bitten on that one! Also, check very carefully on shift kit instructions. If it says drill a hole in the case at the accumilator, read the year model and be very sure you have the right year model. Another bite- big one. Trashed a good 727 case. Pay close attention to clearances. End play and clutch clearance. Your old seal(clutch piston) and new ones may not be identical(smaller lips). There is only one spot each one will fit in. They are different diameters. One tip on piston seals,if I can accurately describe it, is to install the new seal on the piston. Clean the piston first. Take the old seal and turn it wrong side out and stretch it over the new one. That will shrink the lip diameter so it will slip into the bore easier. While you are cleaning/inspecting the rest of the assembly should be enough time(at least 30 mins). If it does not slip in easily use the edge of a feeler guage to tuck it in. Be sure there are no burrs on the edges. Patience is key here. Use plenty of lube throughout. Newspapers make good table cloths for the work bench and are easy cleanup. Make sure to lube the front pump gears with a heavier lube. If you don't have assembly lube for AT's vaseline will work aok.

Hope that helps. Good luck!