fluid leaking between tcase and trans . have change seal 3 times ,cleaned surfaces, replaced with double lipped seal, still leaks yes I checked tcase seal not leaking from there. had trans rebuild after 220000 miles never leaked before rebuild. any Ideas to fix it besides sealing flanges where they mateup ?

All I could suggest is some emery cloth on the surfaces, and the The Right Stuff is a very good sealant. (the best, in fact)

seal surface has a mirror finish, is there anything in the od. unit that could cause this ?

Them seals are kinda forgiving, is it leaking between seal and shaft or seal and case, may have a scratch in shaft or something is lose like a bushing or bearing and causing vibration. Sometimes a seal can roll inwards on install and is not sealing on surface it was designed to seal on. Had that happen on a crank seal on a car. On my truck I have a small leak on a seal that comes out of back of tcase outputshaft. Changed twice still dripps, there is a bushing I'm thinking of changing but my driveshaft maybe vibrating, it's leaked ever since I had a well known driveline shop put new u joints in and balance. Went back and had them rebalance it stood and wached and machine said it was good. 

 another thing is make sure all your vents are venting, if a vent is plugged it will create some pressure in the case and push fluid out. That's how I ended up changing my wheel seals before they needed to be changed, my rear end vent was plugged.

thanks for the response I will look at all those things , see what I find

I have a leak and was told that the bushing needs to be changed if you have trouble sealing the seal on either end of the transfer case.  I haven't gotten around to finding the bushing.  It is easier to buy parts than to actually install them.  I'm waiting until all current parts are on the truck before ordering more. 

 

Does anyone have a source or is the bushing easy to find?