exhaust gasket?

[240inCO]

i recently had to take my transmission out because it was stuck in reverse, well after i got that fixed and put the transmission back in my exhaust has been sounding like a lawnmower ( i took the exhaust apart when i took the crossmember on the trans off ) i was wondering if there was a gasket that i didnt know was there and i lost it or damaged it. by the way i have an '89 240sx and the crossmember was bolted to the exhaust pipe

[daniel240]

there are gaskets on both sides of the 2nd cat which im sure you took off.