The Stovebolt Site Forums The Shop Area Driveline 3-speed wash out

I picked up an SM318 3-speed transmission yesterday and want to clean it up both outside and inside before I install it. After I drain it, would there be any harm in filling it with either diesel or gasoline, slosh it around, and then drain it? I’d like it to be as clean as possible before I refill it with clean transmission oil. Thanks

Diesel fuel should work just fine, it won't leave a lot of residue or varnish. If it's really nasty you may want to soak it in a solvent tank.

I didn’t know if diesel or gasoline would damage anything inside like seals or bearings. I’ve never been inside a tranny before. Thanks

Diesel is less volatile and safer. Of course, still use it outside with plenty of ventilation.

Fill with Diesel and use a big drill motor to spin the input shaft. Drain and refill with 90 weight GL-1 lube, not some super slippery synthetic
Jerry

Thanks Jerry. Sure glad to see you’re back and making comments again in the Forums! Glad you’re feeling much better!!

You could bring it to a machine shop and have it hot tanked. Had a shop do an intake manifold once and it looked new. Just no aluminum!

The Oakite solution that was once used in hot tanks is illegal these days due to "environmental" panic. The greenies will trump up huge fines for anyone who tries to use any sort of an effective hot tank cleaner, so those tanks have been replaced by industrial strength motorized pressure washers that use something resembling commercial dishwasher detergent. The trans would have to be completely dismantled to benefit from that kind of cleaning.

Oakite and similar caustic hot tank chemicals would eat the brass and bronze parts of the transmission, even if you could find someone who still operates a hot tank illegally.

Jerry

I've used stuff called Oil Eater in a small parts washer. It's mixed 1:10 with water and does a reasonable job. But I think it's citric acid based, which probably wouldn't do for an assembled tranny.

If you really don't want to disassemble the trans just pull the cover and spray it out with several cans of brake cleaner. It will take all but the heaviest crud off and still won't leave a residue. like the others here I would recommend replacing the seals while your this deep in it.

The owner's manual for my '47 Diamond T recommends using diesel fuel to clean out the tranny and differential when changing gear oil (on the truck). The tranny is a Warner T-9, non-synchronized four speed. I would not recommend gasoline for the safety reasons.
Kent

Mineral spirits works fine, too.

Ed

I put mine right in the parts cleaner. Got it from a friend and looked like he found it in a creek. Been using it for 5 years sinced cleaned out. Works good.