Can I replace the rear main seal without taking....
- Thread starter duneFJ40
- Start date
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I'm guessing you have never seen the seal or otherwise you would know.........
no flywheel has to come off
Make sure it is engine oil.
Many times the seal between the T-Case and T-mission goes out. The end result is the T-case fluid is drawn into the transmission. The transmission is then "overfull" and may leak out the front input shaft.
A quick check of the fluid levels will tell you if this is happening.
The rear main seal on the engine is about 3.5" in diameter and as previously stated, you have to remove the T-case, transmission, clutch assy and flywheel.
If it is the rear main seal, run a compression test on the engine. If you have a cylinder with low numbers, you could be experiencing blowby. Blowby will increase lower crankcase pressure. Make sure your PCV is working correctly. If it is stuck, the crankcase pressure will build to the easiest leak which is generally the rear main seal.
Many times the seal between the T-Case and T-mission goes out. The end result is the T-case fluid is drawn into the transmission. The transmission is then "overfull" and may leak out the front input shaft.
A quick check of the fluid levels will tell you if this is happening.
The rear main seal on the engine is about 3.5" in diameter and as previously stated, you have to remove the T-case, transmission, clutch assy and flywheel.
If it is the rear main seal, run a compression test on the engine. If you have a cylinder with low numbers, you could be experiencing blowby. Blowby will increase lower crankcase pressure. Make sure your PCV is working correctly. If it is stuck, the crankcase pressure will build to the easiest leak which is generally the rear main seal.
It is a good time to go ahead and do your clutch assembly as well, with the right tools and a cherry picker, this really is not a bad job, and I am not a mechanic...but it could be done in a weekend with some good tunes and and a few drinks. With you and a buddy...even if you needed to do the clutch and have the flywheel turned, just line up the machine shop and you can be in/out in an hour, I dropped mine, had it turned while I went to lunch and it was done when I got back.
Good luck
Good luck
not that big of a deal to do....i was pretty worried about dropping the stock trans and putting in a SM420 cause it was a "modification" the worry was very unwarranted...went off without a hitch, if your going to be doing this tho i would say get a buddy to help you and have an cherry picker or some way to lift/controll that transmission, not just trying to wrestle it into place yourself...good luck! oh..and yes you do have to pull the trans, case, clutch yadda yadda as others have said, but not a big deal...weekend and a case of beer and your set
If you have the stock engine you have to pull the trans transfercase but on an older sb chevy you dont they have a 2 piece rear main seal.
- Thread starter
- #9
Thanks for the replies. I think I will take it to my buddy's garage and use his lift. So, the parts I need...
Main bearing seal
oil pan gasket
clutch disc and pressure plate
throw out bearing> (Do they use those on this rig?)
Thanks!
Main bearing seal
oil pan gasket
clutch disc and pressure plate
throw out bearing> (Do they use those on this rig?)
Thanks!
LAMBCRUSHER
SILVER Star
Highly recommend dropping the pan and loosening the main cap. Also, if you are slightly lifted, an atv jack made ez work of lowering the trans/transfer assy. Couldn't hurt to swap out the 4 dollar pilot bearing as well. Don't forget to get that flywheel surfaced....Check your oil galley plugs at the rear of the block....
