mmb617

I have an '03 Yukon Denali with 107k on the clock. Just recently it's started having what I'm afraid is beginning of the end for it's 4L65E. Sometimes when I try to pull out, it doesn't want to go and it makes what can not be a good noise from the transmission. It doesn't just slip, as in the engine revs but vehicle no go, but instead it's like I'm in mud so thick I can't push through it, and it's being held back. After 10 seconds or so it will pull out and shift normally (at least so far).

I've rebuilt manual transmissions before but never did an automatic. What I'll probably wind up doing is buying a rebuilt transmission and swapping it out myself. I keep running across the name Monster Transmissions as a source. Their prices seem good and they offer a heavy duty option for not much more that the standard build. Mine is completely stock but I'd spring for the HD version just for peace of mind.

Have any of you bought from Monster Transmissions?

Anybody want to armchair diagnose my problem?