Before you start pulling the tranny,did you try flushing it out and giving it a new filter and fluid? I've had a couple of 'em that responded to just a service and lasted quite a while with no problems. This might not do any good,but if it does,look at all the money and work you saved yourself.
Speed


1954 GMC 350
1957 GMC 1/2 ton
1962 Chevy C-30
1952 Chevy 6400 dump bed project truck
'98 Harley FLSTC
'66 Pontiac Catalina
'76 Chevy 1 ton Duallie
'84 Bronco II
'78 Dodge W-200
'81 Toyota 4X4 truck