Hi I own a 1975 Monte 350. I have an oil leak on the lower passenger side of what looks like is the oil pan. After some researching in my Haynes manual it seems a better idea that it could be the rear main oil seal that is leaking. Since I would need to remove the oil pan to do this I may as well replace both seals. Now my question is it doable to replace these seals with the engine and the automatic transmissioni n place or do I have to remove one or the other. My Haynes book does not say to remove them but I seen others on the web saying you have to. Any assistance would be greatly appreciated. Thank you

 

I replaced the rear on my 85 SS and you have to remove the oil pan, but you don't have to remove the engine or the trans. I just had to jack up the engine and hold it in place. This means you have to disconnect it from the mounts, both engine and tranny. Now, is this a pre-86 block? 86 and after went to a 1 piece seal so you would have to drop the trans to replace it. The front seal is in the front cover so you have to remove the balancer.

 

Ya it's an original 75 block. I seen there's a 2 piece seal that you can get which means only removing oil pan and what may be in the way. I'm thinking I can do it without removing tranny or block but not sure and don't want to start a job and turn into a huge thing.

 

Yea, you don't have to remove the tranny. You do have to remove the rear crank bearing cap to tap out the seal half. I was reluctant to do that at first but it wasn't too bad. You will need a torque wrench for sure.