440 rear main seal

[Bigal75]

How nasty is it to change a rear main seal on a 440? Just went for a ride and I could smell burning oil, went back home and let the car idle and looked under the car and oil is dripping (heavily) out of the transmission/block area. Is it a common issue?

 

[67 B-body]

Double check to be sure it's not coming from the valley pan area. They can leak back their and run down making it look like a rear main seal.
As far as easy to replace the rear main.... No, it's not and will most likely require removing the engine from the car to replace it.

 

[bigmanjbmopar]

It can be done with the pan off and removing the rear main cap, you can use a very small flat blade to tap out the half round seal from behind the crank and re install it the same way, leaking rear mains are common and you get to the point of just ignoring it i guess lol. I got a set from 440source and have been good, but I 'm sure it will leak in another 2000 or so. good luck.

 

[lewtot184]

it can be done. remove center link and pan. remove seal retainer. you'll probably have to pop all the main caps loose to drop the crank a little. fish out the seal half in the block. then reinstall seal/retainer/side seals. re-torque the caps keeping in mind to retain crank end play. the real issue is "why is it leaking?" try to trouble shoot that when things are apart. make sure you don't have a trans seal issue too.

 

[Bigal75]

it can be done. remove center link and pan. remove seal retainer. you'll probably have to pop all the main caps loose to drop the crank a little. fish out the seal half in the block. then reinstall seal/retainer/side seals. re-torque the caps keeping in mind to retain crank end play. the real issue is "why is it leaking?" try to trouble shoot that when things are apart. make sure you don't have a trans seal issue too.

Well I can tell that it's engine oil, transmission seems OK. I assume its from sitting, perhaps it was incorrectly installed at one point?

 

[Bigal75]

Double check to be sure it's not coming from the valley pan area. They can leak back their and run down making it look like a rear main seal.
As far as easy to replace the rear main.... No, it's not and will most likely require removing the engine from the car to replace it.

Right, I didn't think of that, I'll check it out tomorrow.

 

[Bigal75]

Just went and checked, the top of the transmission where it bolts the the engine seems oily as well, might be the oil sending unit? Valley gasket, like someone mentioned?

 

[poly1963]

you have to rotate it about 1/4 inch so the ends of the seal are not in the same place as the cap and block because the cap bolt holes have a little space in them i have had this problem before with top quality seals i found this tip in old hotrod magazine years ago

 

[lewtot184]

Just went and checked, the top of the transmission where it bolts the the engine seems oily as well, might be the oil sending unit? Valley gasket, like someone mentioned?

hopefully thats it! laying under them with the pan off is real gooey. oil pressure sending units are real bleeders if cracked.

 

[65-440]

i thought my rear main was leaking a while back too. turned out to be the 2 oil pressure ports on the back of the block. both were leaking, and the oil would run around the bellhousing and drip right from the inspection cover ! ..... not to mention valve cover gaskets leaking too !

 

[Bigal75]

Yep, went out and the sending unit is sitting in oil, theres a little 'nook' in the block and it's full of oil too.

 

[65-440]

Yep, went out and the sending unit is sitting in oil, theres a little 'nook' in the block and it's full of oil too.

alot better than a rear main repair !!!

 

[Bigal75]

alot better than a rear main repair !!!

You got that right! Its pitch black outside and there's no way I was going to bed without knowing for sure!

 

[65-440]

You got that right! Its pitch black outside and there's no way I was going to bed without knowing for sure!

haha, i hear that ... now you can sleep well !:icon_thumright:

 

[brandon64]

you have to rotate it about 1/4 inch so the ends of the seal are not in the same place as the cap and block because the cap bolt holes have a little space in them i have had this problem before with top quality seals i found this tip in old hotrod magazine years ago

Thats a darn good idea. I'm going to try it. Thanks