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Old 01-07-2012, 10:57 PM
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Default Rear main seal leak question

I have a 2000 Chevy Trailblazer that has 60,000 miles on it. It in great condition other than it appears that the rear main seal is leaking. Has anyone here have to have their replaced at this low of mileage? Is it worth having it replaced, or should I just trade it off on something else??? Also does anyone here have an idea of what it would cost to have this done??

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Old 01-07-2012, 11:04 PM
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Is it worth it if you can do it yourself? Yes
Is it worth it if you want to keep the vehicle and the oil inside it? Yes
Is it necessary? No as long as it's not a big leak and you keep the oil at the proper level.
It's definately going to cost more than you are going to want to spend but I don't think it would warrant trading it in just because of it.

I would make 100% sure it's the rear main seal before you jump to conclusions though. You might get lucky and it's leaking from somewhere else.
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Old 01-07-2012, 11:46 PM
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Pull the rubber plugs (2) off the front of the trans underneath and have a look at the flex plate. If the flex plate is covered in oil, then the rear main is leaking. If it isn't, then check your oil pan bolts. I had very much the same problem with my 2000 Bravada at around the same mileage. It ended up being the oil pan bolts loosening up. Tightened them up and it stopped leaking for a bit then started again. On the 2nd time, I removed each bolt & cleaned both the bolt & the hole it went in. Then used some blue loctite on the threads before putting it back together. 20k later and it was still dry underneath.

A few other areas to check include the back of the block where the lower intake manifold meets the block as well as the gasket on the oil cooler/filter adapter on the driver side of the block. Both can make oil drip down around the bell housing & make a mess under the truck that may seem like a rear main seal leak.
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Old 01-08-2012, 12:13 AM
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Gale is an unknown quantity at this point

hammy we just pulled/installed two 1998 4.3's this last week. The one with 524K miles rear main did NOT leak. The one with 119K miles did not leak at the rear main and the flywheel on each were dry.

We did go to GM and get a new rear main seal for $40 for the 119K mile engine since they better built then FelPro after market rear main seals from what I could learn while it was on the engine stand.

It was a good running engine when pulled from a 4WD auto 1998 Blazer but it was wet from top to bottom with engine oil and had OEM intake manifold gaskets. So when on the engine stand we stripped it down to a long block and came back with all new gaskets before installing it into the S10.

At 119K miles the OEM intake manifold gaskets looked like wet cardboard and were sure to fail sooner than later.

Short of a factory defect you do NOT have a rear main seal issue as others have noted. Even then only a 5-speed would make me concerned. Lost a Datsun clutch many moons ago due to a leaking rear main engine seal. Well the clutch was not worn out but sure was slick.

We were putting the 119K in front of a 5-speed. Manual transmissions do push the crankshaft forward a bit each time you let out on the clutch so they may get a bit more stress but the OEM rear seal was fine after 524K interstate miles chasing new mobile homes across the country. The flywheel had a grove cut in it by the clutch band.
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