Quote:

Read the Allpar link. It says that newer ATF does not play well with old style trans seals and will cause leaks.



Been there, done that. I changed the fluid/filter in my 727 and thought I'd upgrade to the ATF+3. With the original (factory!) seals in the trans and ATF+3, the front pump seal leaked like a sieve! It would lose more than a pint sitting overnight. I didn't have alot of time to "fix" the problem so I thought I'd buy some time by keeping a case of dexron in the trunk. By the time I went through 2/3 of that case of fluid, the leaks stopped.

I'm sure that a rebuilt trans can have gaskets put in it that are compatible with ATF+3-4-5, but don't try it with older rebuilds or original trans' unless you want a red lake in your driveway...