1998 GMC 1500 Suburban
 

Can anyone tell me if there's a gasket between my transmission oil cooler tube mount and the radiator bushing nut? There looks to be some heavy residue on the rim and may be an old degraded gasket. I'm getting steam from that area> Thanks

If they were manufacture of two different materials.... I would have to guess YES.
There should be a gasket separating the two.

Sorry I can't give you a definitive answer