Rear main seal on a 2000 5.3

[ncsu602]

I've been chasing an oil leak on my 2000 4wd 5.3 for about a month and I'm afraid it's the rear main. The truck has 156k on it and never leaked a drop until a couple of months ago. It drips off the bottom of the bellhousing, drain plug, starter bolt, and the pan bolt beside the oil filter. The oil pan gasket has 100 miles on it, the oil cooler blockoff gasket has 200 miles on it, and the oil filter has 500 miles on it. I put dye in it yesterday and checked it last night, I've got oil on the back of the pan in side the inspection cover but none on the flywheel. I checked the back of the intake and didn't see anything, but honestly it's tough to see even with a mirror and the dye I bought was horrible. It wasn't nearly as bright as the stuff I've used in a/c systems before.

 

Is there anything else it could possibly be? I've done rear main seals, clutches, we did the oil pan gasket a few weeks ago, etc. I've never pulled the trans and transfer case on a 5.3 though. Is there any tips or tricks? Do you need a special tool? Is there an updated gasket? Sorry for the questions, I just don't want any suprises when we tear into it. Thanks!

[AirForceAngler]

Was it leaking before you changed those other gaskets? I've not heard too many issues of the rear main leaking on these engines, not to say it can't happen. Removing the trans and transfer case is pretty straight forward, no special tools required by a trans jack would be helpful. It may be easier to pull the t-case out separate to reduce the weight and bulk. I changed the engine out in a 2000 and it wasn't too difficult. I left the trans and t-case in when I did it so pulling those separate shouldn't be too hard. The hardest part is getting to some of the bell housing bolts up high on the back of the engine. Just make sure you get ALL wires and ground straps undone so you don't pull them apart.

[ncsu602]

Thanks for the reply. It started leaking and I started throwing gaskets at it. I know the oil pan was leaking, it cured half of my issues, so it wasn't money thrown away. I thought it was the oil pan gasket because when I checked the inspection cover on the trans, it wasn't dirty. It's spotless inside as far as dirt, but has a coating of clean oil since I just changed it. That was where most of the dye was. I'm not too concerned about pulling the trans, I've owned two 93-02 camaros and had the trans out of both of them. The top bellhousing bolts are under the dash and an absolute pain to get to. I've got a trans jack.

 

Does anyone know if the torsion bars have to come down too? I'm assuming they do due to having to remove the crossmember.

[nickvrebel]

I've pulled the transmission on a 2000 4wd many times. It's fairly straight forward if you have pulled an automatic transmission before. After about the 3rd time we just started leaving the transfer case attached to the transmission, it was too much trouble handling it separate. Gear wrenches will be you best friend. You just need sockets big enough for the crank bolt (only way to spin the converter to get to the bolts on it) and the transmission cross member. I think stock bolts on the converter are torx, but I can't remember now.

[nickvrebel]

torsion bars do not have to come down, you are only removing the front crossmember where the transmission mount is, you can slide the transmission back and get the truck high enough to get the transmission down and out.

[ncsu602]

Sweet, doesn't sound as bad as I though it would be. Thanks alot, I'm gonna try to tackle this in the next few weeks.

[gmtech4]

t case has to go first ,leave the torsion bar crossmember onlone ,,then the tranny,lowering the tranny slightly after its crossmember goes leaves the upper bell housing bolts visible and easy to bark off with a 2 ' 3/8s extension and a 15mm swival impact socket,,

 

15mm stubby rachet wrench for the t case nuts

 

trust the tranny guy !! lol

[ncsu602]

Anyone know if the rear cover for an aluminum block 5.3 will fit my LM7 iron block? GM sells the entire rear cover assembly with new bolts, gasket, and seal already installed for about $40, p/n 12633579, and the seal itself is $15. I'd rather buy the whole thing if it'll fit. The updated cover was released with a TSB 05-06-01-034J that had to do with porosity issues with aluminum blocks. They should be the same, but I'd like to make sure before I ordered the part.

[Gurrzt]

At first I thought I had a leaking rear main seal on my 01 Z28 (Sara), when the mechanic isolated the leak, it turned out to be an oil pressure sensor that was cracked. This sensor sits behind the intake manifold, and over time the heat of the engine is known to crack and cause it to leak.

 

This MAY be the cause of your problem.

[ncsu602]

Well, I'm still hoping thats what it is, but I'm almost positive its the rear main. I put dye in it, which wasn't very good, and you can't see much on the back of the intake without taking it off. No visible dye on the intake and definite oil in the bellhousing. I've got access to a lift, so hopefully we can knock it out in a day.

 

On the other hand, I'm sure that's where my 99 Z is leaking from....must be a camaro thing.