To flush or not to flush an AT.
To flush or not to flush an AT. Some shops say it's good to flush an AT but some shops also say it's NOT good to flush an AT 'cause it's a foreign fluid.
If just drain and fill will not drain 'all' the fluid, than does that mean if flushing an AT, some if not most of the flushing fluid remains in the trans and will mix with the new fluid??
Some people say to just drain, fill and drive x3. Well, I don't have time let alone money to keep buying trans fluid.
So is flushing good or just drain and fill is better than nothing.
If just drain and fill will not drain 'all' the fluid, than does that mean if flushing an AT, some if not most of the flushing fluid remains in the trans and will mix with the new fluid??
Some people say to just drain, fill and drive x3. Well, I don't have time let alone money to keep buying trans fluid.
So is flushing good or just drain and fill is better than nothing.
The thing is how bad is the fluid contaminated? Do you see clutch material in the oil? If so, then tranny is done and about to go out. Not even worth it because u will just contaminate the new oil. If it's not then u need to do a flush witch involves more then just taking the pan down and resealing it. Need to take everything out the torque converter and the cooling lines. That's the best way to do it. Also now dexron 6 should be used on on the 4L60E
flush with transmission fluid not additives and your good. drain and fill is for fluid thats just kinda discolored sorta like halfway between red and brown. if your fluid is dark brown or darker you would do a flush.with that said its always a good idea to run the fluid you are taking out into a clean bucket because if it comes out with clutch material in it and its all chunky/black death. you want to put that fluid back in the trans. flushing or draining fluid with new fluid at that point would be a disaster since thats the only thing keeping that trans going at that point. use it as you wish but its time for a rebuild. hope that helps
TECH Resident
Joined: Jan 2002
Posts: 877
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From: Poway, Ca. where GOD and the sun always shines
If you transmission fluid is that dirty, change both, and @ 1k change both again, that should clean you up abit.
SteveC
