I've got a '68 F-250 with a C-6 hooked up to a 390. I had the tranny rebuilt a little over a year ago and it works very good.

The problem is it has sprung leaks from what seems like EVERYWHERE. After the rebuild, I asked the tranny guy what type of fluid I should use. He recommended Mercon in lieu of Type F, thus I have always used the Mercon. I have since "heard" that using the Mercon can cause leaks like I've got (you should see the oil slick on my garage floor). Is this true? Should I switch back to Type F or am I just wasting my time.

Thanks for the help.

 

Huh, can't beleive he told you to use Mercon vs type F. I have heard from a some reliable sources that they use and was recommended Type F in modified Turbo350's and 400's and a few others. One sorce also said all that the B&M stuff is is Type F with some color tint in it.
I know Tpye F is much thicker fluid. Unless he used some kind of funky seals I can't see Mercon causing a leak just shifting problems.
I'm not 100% on this, I really don't know what to tell ya to use.