Rep Power: 118

Hello everyone, my car has developed a pretty bad oil leak about a month after I replaced my transmission. The oil is definitely coming from between the engine and the transmission, so something happened to my rear main seal. My question is if it is likely a coincidence that the seal started leaking after I replaced my transmission or if something is wrong with my new/used JDM SLXA transmission that is causing the seal to leak. I have read that a bent or warped transmission shaft or torque converter can stress the end of the crankshaft and cause the seal to fail, so the last thing I want to do is spend a day changing the seal only to have the same thing happen again after another month. So should I just change the seal and hope for the best, or is there something I need to do to verify that the transmission didn't cause the failure? Thanks a lot in advance!

 
Rep Power: 367

which is leaking?
both have fluids inside
open them up. My crystal ball is on vacation.

 
Rep Power: 118

Sorry, I should have specified. It's leaking engine oil.