here is my question. I rebuilt the trans several years ago and worked fine. one week ago blew a cooler line. fixed line put in 8 quarts and drove for 3 days like nothing happened. worked same as always. then it started slipping when shifting to 3rd. not really slipping its just like there is nothing there, like going into neutral. I can manually put back in 2nd and its fine. just totally disengages going into 3rd. but some times it will stick when shifting to 3rd and feels very solid, no slipping. then it will just completely let go. any ideas?

This is the 3-4 clutch. If you lost this slowly, then the clutches are burnt, if this happened all at once, then you might have broken the input drum lugs that hold the 3-4 clutch snap ring.

just drove it tonight, works perfectly for about 10 - 15 miles cold. (its single digits here). as it warmed up it had trouble holding in OD. finished the trip in D. held third as long as not in OD after warming up for 10 miles. earlier today (30 degrees outside) could not get above 2nd. seals?

no, not the seals, you just finished off the 3-4 clutches as Dana said.

oh well, can't avoid the inevitable. guess I'll be pulling it in a few weeks.

I pulled it apart today and the 3-4 clutch is wasted. for what it's worth everything else looks almost new (110k on last rebuild). what I am wandering is can i increase the pressure to the 3-4 clutch easily? after reading differing opinions on the max-pack and z-pack and the fact that I have 4.3 and the cost, I purchased a Pioneer kit with bushing kit. I am wandering if I can drill a hole or something to give just a little more holding power in 3-4. any help is greatly appreciated. thanks.....Jason