1957 transmission flushing

[twstnshout]

Working on a body off 57 restoration. 3 speed overdrive. I drained the 50 or 60 year old goop out of the transmission. Looking for best method to flush the transmission out?

 

[HKelly]

Put new fluid in it and a filter if it has it and run it for a bit. Then repeat.

 

[twstnshout]

Yeah sounds good but that’s probably 2 years in the future. Lol

 

[Ward 57]

Yeah sounds good but that’s probably 2 years in the future. Lol

If it's going to be that long before you re- install it, I'd send it out to a rebuilder. If there is that much gunk in it you don't know what else is in there. Don't take the chance of having to pull it out later because of a few $. You want to be able to trust it.
Same with my booster. When I had my shop rebuild it , it was full of fluid and junk where it shouldn't be pumped into it from a rusty M/C reservoir even though the M/C was still working fine. pulling the M/C and rebuilding it and flush the whole system. Yah life got in the way and didn't due proper maintenance .

 

[74 Harley]

Manual transmission has no filter. If it was really nasty you can use diesel fuel as a solvent to clean it out. About a half gallon and let it sit a few days.