LS1GMCTruck

iTrader: (2)

If you overfill a 4L60E transmission with fluid, say a quart or so more than it should have, how will the transmission react? I have an aftermarket dipstick and question its accuracy. Thanks

Mike@Century

We have run them up to 1 qt over with no side effects. If you overfill too much it will puke out from the breather tube. It's way better to err on the over fill side than to not having enough fluid.

LS1GMCTruck

iTrader: (2)

Thanks for the quick response/answer. Thank-You Mike.

mike13

iTrader: (27)

This is what I've been told, error on the side of overfill by a little, so if you look at the dipstick run it at the full line not in the middle or bottom. I was told if you it to full not only will it puke out the vent tube but can cause the oil to froth or foam because it's getting whipped by the internals.