rear main oil seal
#1
03-03-2007, 08:42 PM
rear main oil seal
I'm new here, hope this question is in the right forum. 1999 Blazer, 4.3, 4wd, AT, 110k.The guys at the oil change shop said the rear seal was leaking.Is there anyway tocheck this without dropping the tranny? I've always worked on my own rides, but they were all 70's and early 80's, this is my first"modern" vehicle. I'll probably have a shop do the work, but I want toverify the problem before I take it in and fork over a grand. Thanx, Mike
#2
03-03-2007, 09:37 PM
RE: rear main oil seal
I had a very similar problem on my Bravada. What I found was loose oil pan bolts. Tighten them down and the problem has yet to resurface after 10k miles.
You will need to remove the rubber plugs from the transmission bellhousing to tighten the two rear most bolts (or just check them). There is also an inspection cover on the bottom of the bellhousing that you can use to look inside. The rubber plugs when removed will give you a good view of the front of the flex plate. If the flex plate is covered in oil, then the oil change place is mostlikely correct and your rear main seal is leaking, but if it isn't covered, then the seal is mostlikely intact. If your oil pan bolts are tight, then it may not be the pan.
Another culprit of oil leaks that get blamed on a leaky rear main seal is the oil pressure sending unit. It is located behind and slightly towards the drivers side of the distributor. If this is leaking, the oil will run down and may seem as though it
is coming from the rear main.
Good luck and let us know if you have any other questions!
You will need to remove the rubber plugs from the transmission bellhousing to tighten the two rear most bolts (or just check them). There is also an inspection cover on the bottom of the bellhousing that you can use to look inside. The rubber plugs when removed will give you a good view of the front of the flex plate. If the flex plate is covered in oil, then the oil change place is mostlikely correct and your rear main seal is leaking, but if it isn't covered, then the seal is mostlikely intact. If your oil pan bolts are tight, then it may not be the pan.
Another culprit of oil leaks that get blamed on a leaky rear main seal is the oil pressure sending unit. It is located behind and slightly towards the drivers side of the distributor. If this is leaking, the oil will run down and may seem as though it
is coming from the rear main.
Good luck and let us know if you have any other questions!
#3
03-03-2007, 11:24 PM
RE: rear main oil seal
Thanx Kyle. I'll look for the rubber plugs tomorrow. I guess that they are there for access to the bolts? Unfortunately, I'm not very familiar with this Blazer. I bought it formy wifein Nov., and I've only been home about six weekends since then. I forgot to mention in my post thatthe Blazer has 110,000 miles (I've edited my original post). I heard of the sending unit leaking in another forum, and they said it was extremely difficult to get at. The only Chevy's I've ever worked on have been '71 or older,so this 4.3 is a whole new beast to me! Thanx again, Mike
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