Leaking Rear Main Seal?

[Geotrash]

20 years ago, I would have jumped into this project, but at 70, I am not up to pulling the tranny with the vehicle on jackstands. And being retired and on a fixed income, I can't afford to have a shop do it. Looks like I will just keep feeding it a quart of oil every month and deal with the puddle under the car.

I totally get it, and there's nothing wrong with that. Important question though: is this a Denali with the 6.2L? If so, you're on borrowed time with the torque converter on that 6L80 transmission. If you have the 5.3, then you have the 4L60E, and this caution doesn't apply. But that may change the cost vs. value equation on whether or not to pay to have the work done. The rest of the vehicle is a 350K+ platform.

The cost to have the work done I mentioned above at a good transmission shop should be around $1500, including the seals and TC.

 

[rustycrocker]

It is a Yukon XL with 5.3. Bars Leaks?

 

[29tomt]

2007 Yukon XL, 170k miles. Have a leak from the bottom of the engine. Cleaned it up and watched for leaks and it appears to be leaking between the engine block and the bellhousing. Guessing it is main seal?


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My 2003 Tahoe with 5.3 and 225K on the clock started leaking. the oil pressure sending unit and oil pan gasket had been replaced not too long ago. Anyway, I took a shot and added a container of Blue Devil 00284 Rear Main Sealer and after several days, the leak stopped. Have seen no fallout. In reviewing feedback from other users of the product, it appears that many had the same engine and also got great results. One can only hope given the cost for replacing the seal.

 

[davidavidd]

Understood. A few other possibilities worth checking before pulling the transmission are:

1/The valley cover plate on top of the engine. Most people find that the gasket takes a set over time and the bolts are barely finger tight, so leaks develop that run down the back of the engine. You can look at this with an inspection mirror.

2/ Oil pressure sender on the top rear of the valley cover plate. Inspection mirror will work here, too.

3/ Rear of the valve cover gaskets. Same deal - leaks down the backside of the engine.

4/ Crank position sensor behind the starter. Look for oil beneath the starter.

If you pull the transmission, replace the rear main seal, rear cover seal, the oil gallery barbell, and the torque converter itself, if it's a 6.2L (6L80) and it's original. This will save you from having to do it again in a year or two. The TC on the 6L80 will eat itself (very few will make 200K), and it will take the transmission with it when it fails.

@Geotrash knows, my bet is for 1 and 3!

 

[Gak9sar5]

20 years ago, I would have jumped into this project, but at 70, I am not up to pulling the tranny with the vehicle on jackstands. And being retired and on a fixed income, I can't afford to have a shop do it. Looks like I will just keep feeding it a quart of oil every month and deal with the puddle under the car.

Put an oil pan under it to catch the drip off the driveway. We use them in the fire department and it works well.