I noticed my truck has a really bad rear main seal leak when it is running. My truck has a 351M with a 4 speed. Do i have to pull the motor out to replace it or just drop the oil pan? and is it a one or two piece seal? Id like to pull the motor so i can put my cam and everything in though.

 

welcome to the 351/400 m rear seal club those motors are bad for that better of to pull the motor that way you can check the main/rod bearings and the seal is a 2 pcs

 

Thanks for the reply. If I pull the motor I think I'm going to do a fresh rebuild. The motor is very strong as it is and runs like a top. Its just the bad leak. There's really no sense in not going and doing a full rebuild if your going to have the motor. out in my opinion. I guess you'd understand