I have a 1966 Saginaw 3spd OD in my 37 truck, the T-85 is BW's code for a heavy duty long tailhousing 3 spd used in the 50-60's for larger engined Fomoco's and some Mopars.The T-85 is the tranny that the T-10 4 spd was devoloped from in 1957.I've always heard the T85N was the OD version of the T85.Be careful of using OD on first gear,it's not designed to carry a great deal of torque.
NortherenGMC, the two trannys are the same length, same front spline and bolt pattern,but the 55-64 Muncie has a non syncro low gear and has the small 4 bolt side cover.The later Saginaw has a finer rear output spline and it's all syncro and some what more rugged.The OD internals are allmost identical, but the cases are different.
