Transmission / Overdrive: T-86 OD bench test

[Phatfenders]

I found a replacement T-86 od trans that so far seems to be in real good condition, but while doing a bench test of the od I discovered a problem that I am would like to get some advice on.
By moving only the od lever on the tail shaft to the rear (od available position) the output shaft would turn about 1/3 faster than the input shaft. I know this because I flagged the shafts. When the solenoid was powered it clicked but did not engage or disengage the od, powered or not. The lever is the only thing that seems to put the od in or out. There is freewheeling when the lever is in the od position. I'm questioning why the solenoid is not switching it in and out of od? Could the sun gears be gummed up? I'm thinking of filling the tail shaft with diesel to see if that might free up something. This trans had been sitting for years indoors and most of the oil had drained out the tail shaft. Your thoughts on this would be helpful, thanks.

[PackardV8]

Can't for certain diagnose by those symptoms, but your suggestion is exactly what I do with any old tranny. Fill to the line with diesel and slosh it around as best you can, let it set overnight and drain.

One T89 tranny I was shipping overseas, it had to be verified as operating correctly. I filled it with diesel, sloshed, drained, then refilled a second time. I then made a jig from a 2"x12" board, strapped the tranny down, mounted a large pulley with a 3/4" bore on the tranny input shaft, an electric motor with a small pulley, a belt between the two. I wired the circuits to a 12v battery. This enabled me to spin it up fast enough to actually verify the governor operated, the solenoid pulled in the OD and the kickdown switch functioned.

Was a bit of work, but much easier on the bench than under a truck. When everything had been cycled successfully, I drained the diesel and the operating under speed had loosened a bit more sludge in there. The tranny was shipped to OZ verified as clean and functional.

jack vines

[Phatfenders]

One T89 tranny I was shipping overseas, it had to be verified as operating correctly. I filled it with diesel, sloshed, drained, then refilled a second time. I then made a jig from a 2"x12" board, strapped the tranny down, mounted a large pulley with a 3/4" bore on the tranny input shaft, an electric motor with a small pulley, a belt between the two. I wired the circuits to a 12v battery. This enabled me to spin it up fast enough to actually verify the governor operated, the solenoid pulled in the OD and the kickdown switch functioned.



Jack, this is very much like what I am doing right now. I have the trans filled with diesel, spinning with motor. While spinning the input clockwise if I move the lever to the rear the out put shaft speeds up by about 1/3 without any sound. About the only good thing I can take from this is that the sun gears are doing there job.