Mike C160 251 #1 Posted June 3, 2022 Greetings. I went to change the oil in hydro transmission today. The manual said it should be 10 W 30. However what came out look like a mix of motor oil and automatic transmission fluid. What should I put back in it? If automatic transmission fluid what type? There are a few to choose from Cheers. Share this post Link to post Share on other sites
oliver2-44 10,068 #2 Posted June 4, 2022 Well it’s too late to say 10w30 and ATF should never be mixed. Either would be correct by themself. If it were me, I would fill it with inexpensive 10w30 as a flush oil to get as much of the ATF out of it as possible. Run it around for a while, operate the lift cylinder a bunch etc. Then drain and refill with something like Mobile 1 10w30. You could also flush with ATF and refill with ATF. The earlier Sundstrand came with ATP. Pros and cons to each. 3 Share this post Link to post Share on other sites
kpinnc 13,080 #3 Posted June 16, 2022 I gotta say it... I've been in several Sundstrand hydros. The cleanest ones with the least visible wear are always full of ATF. Not a close comparison mind you, there is no comparison. There will be no corrosion, no discoloration, and the internals look like the day the gears were cut. Unless your transmission is worn to the point that heavier motor oil is needed to keep it going, ATF will be what I recommend and use in a Sundstrand. Share this post Link to post Share on other sites
