Transaxle flush?, to diesel or not to diesel Options

[Cliff 914]

73 side shift. Car has not been on the road since the late 80's.
trans and engine is out of the car and separated.

I have degreased/scrubbed/power washed the transaxle (I plugged the vent hole).
I just drained the fluid out, finding a bit of paste stuck on the drain magnet.

Since everything has sat and settled for the past 30 some years, I was thinking of "flushing" with a bit of diesel fuel. Not much (maybe 1/2 or 1 qt), just enough to help lift some of the goo off the bottom to drain out. Once all back together and running, I would do another drain and fill soon.

My question is, can I pour some down the vent hole to end up at the bottom? Has anyone else flushed it like this?

The car is rough. Has not ran in a very long time. Not too worried about some small residual diesel in trans.

Thanks everyone!

[VaccaRabite]

I don't think I'd do that. Drain it. Fill it with gear oil. Run it.
Its important not to overfill it. You just fill till the gear oil starts to drip out of the filler port on the side.

If you dump diesel in through the vent you now have a much thinner weight oil coating all the top stuff that may or may not drain out completely, and may stop your much thicker gear oil from sticking and lubricating like its supposed to.

Zach

[mjrrti]

I had a trans that had been sitting for years and had the shift console out of it while it sat. From what I could see with a flashlight peeking in the shift console hole it looked plenty dirty. I drained what little gear oil it still had in it and filled it with diesel and used my cordless drill to spin it in all gears I think for about a minute each. I don’t remember what I used to connect the drill to the input shaft but I think it was bigger than my 1/2” chuck so I adapted it somehow. Maybe a 12 point deep socket that fit the clutch splines? The diesel looked nasty when I drained it but inside the trans looked pretty good. I put it in my car with fresh oil and drove it for about 100 miles. Since diesel is so oily anyway I think any tiny amount left after the flush just mixed in. The 100 mile oil looked decent when I drained it for fresh. I changed the oil again and have been driving it since. Maybe I got extra lucky but so far no problems after about a year.

[stownsen914]

You'd get an effective "flush" by filling it, running it for a bit, and draining again while hot.