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06 silverado oil leaks

79rustyk10

79rustyk10

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Ive got an 06 1500, L33 5.3, 4l60e, ten bolt, 180k on it.

Ive got a noticeable engine oil leak, and a noticeable differential leak.

Have any you guys replaced an oil pan gasket, or rear main seal? Is it worth trying to do in the truck, or just easier to pull the engine, and get all the oil pan, rear main, and timing cover all at once? It had a slight wet spot above the starter when i bought it, im guessing/hoping its the oil pan. I might be trying to justify pulling the engine, to make a cam swap a little easier.

The rear dif is leaking also. Im at my breaking point with that one. Tried everything i can think of. Used ultra blue rtv. Ultra blue with a gasket. Right stuff with no gasket. new dorman thick cover with gasket, and right stuff. The ****er still drips noticeably. What am I doing wrong? I have noticed since the last time, the cover bolts seemed to loosen up, and after tightening them the leak stopped for a month. I havent had a chance to get under it yet. Is my main problem reusing OEM bolts? I see online GM recommends replacements, whats the difference?

I also have Mobil 1 synthetic, in both the engine, and differential. I have used synthetic since i bought it over two years ago. Would switching back to dino oil help at all?

Thanks in advance, guys.
 
We do rear main seals in the shop by pulling the trans. Oil pans rarely leak on these things, but it can happen. It's just not very common. Timing covers rarely leak on them either. My money would be on a rear main seal or gasket for the oil cooler line fitting or block off plate if it wasn't equipped with the cooler.

Keep this in mind, there is a GM bulletin out there about a potential porosity issue at the back of the block on 4.8's, 5.3's and 6.0's. Most if not all of the time we found the leak at the rear main seal was the housing itself wasn't sealed to the block correctly. The housing is sealed with the standard gray rtv sealant GM loves to use. We find a gap in the sealant. We typically replace the housing as a unit with the seal so we can make sure that is sealed up right. Replacing the seal only could miss that issue and you'll be back again. The assembly is not crazy expensive, but worth replacing the whole thing.

Oil pans can be pulled without removing the engine. You do have to remove the front diff to gain the room needed.
 
ZooMad75 said:
We do rear main seals in the shop by pulling the trans. Oil pans rarely leak on these things, but it can happen. It's just not very common. Timing covers rarely leak on them either. My money would be on a rear main seal or gasket for the oil cooler line fitting or block off plate if it wasn't equipped with the cooler.

Keep this in mind, there is a GM bulletin out there about a potential porosity issue at the back of the block on 4.8's, 5.3's and 6.0's. Most if not all of the time we found the leak at the rear main seal was the housing itself wasn't sealed to the block correctly. The housing is sealed with the standard gray rtv sealant GM loves to use. We find a gap in the sealant. We typically replace the housing as a unit with the seal so we can make sure that is sealed up right. Replacing the seal only could miss that issue and you'll be back again. The assembly is not crazy expensive, but worth replacing the whole thing.

Oil pans can be pulled without removing the engine. You do have to remove the front diff to gain the room needed.
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Thanks for the good info. Hopefully today after work i can get in for a closer look.
 
So diff cover bolts were all loose. Wtf. Torqued them all to spec. Do i need lock washers, loctite, or new fasteners? Ive never heard of this happening.

Oil cooler block off plate wasnt as tight as one would think. Tightened that. Pulled inspection cover from bellhousing, and its almost completely dry inside so i can count on the rear main, and rear man housing gasket to be good? The rear half of the oil pan was pretty wet with oil, from both sides. Tightened all the rear pan bolts slightly. Nothing was coming from above. Will try to get a couple pics before I hose it all off with brake cleaner.
 
It sounds like you might have found the source of your leaks. Not sure why the oil pan bolts would be coming loose unless someone changed it already and didn't tighten it up properly. If that doesn't dry up you should be able to swap it from underneath but it isn't easy. In regards to the differential, if you have not done any work on it previously the bolts on the diff might be coming out due to excessive heat (generated from excessive wear and low gear oil). If you put your truck in gear and hear a ping sound or can tell that the drive shaft has a heavy rotation without the vehicle actually moving you might have a lot of wear on that ring and pinion, or the bearings and the pinion seal, especially if fluid has been leaking out and the diff doesn't have enough lube in it. 180K is a ton of miles to have a leaking diff that is a 10 bolt so check that play in the pinion setup and check your oil level in the rear end. Might be time for a replacement (or a good pick and pull substitute), to remedy the possible wear issues.
 
rpcraft said:
It sounds like you might have found the source of your leaks. Not sure why the oil pan bolts would be coming loose unless someone changed it already and didn't tighten it up properly. If that doesn't dry up you should be able to swap it from underneath but it isn't easy. In regards to the differential, if you have not done any work on it previously the bolts on the diff might be coming out due to excessive heat (generated from excessive wear and low gear oil). If you put your truck in gear and hear a ping sound or can tell that the drive shaft has a heavy rotation without the vehicle actually moving you might have a lot of wear on that ring and pinion, or the bearings and the pinion seal, especially if fluid has been leaking out and the diff doesn't have enough lube in it. 180K is a ton of miles to have a leaking diff that is a 10 bolt so check that play in the pinion setup and check your oil level in the rear end. Might be time for a replacement (or a good pick and pull substitute), to remedy the possible wear issues.
Click to expand...

Ive had the cover off a few times. i changed all fluids shortly after buying the truck with 120k on it, and have been fighting the diff cover since. Inside, its still in pretty good shape still.
 
Good to know. Glad things seem well still. Definitely better than the alternative.
 
rpcraft said:
Good to know. Glad things seem well still. Definitely better than the alternative.
Click to expand...

Thanks. having a 180k mile gov loc scares me, but its mainly highway miles. Ill update more after i figure more on the engine leaks
 
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