So I'm replacing the main seal in my 5.3 pull out cause I accidently tore it when installing the rear cover plate. The motor is somewhere between a 00-03 and I'm having troubles finding a seal that matches the stock seal.

Gm on the left and Federal Mogul/National on the right

Gm left and Napa SKF on the right


Has anyone else replaced a rear main seal on a GENIII Ls engine and had this issue or is it just me? the Federal Mogul seal number was cross referenced with the stock seal and the guy at O'reillys gave me it. I was leary do to the fact its no where near close to the same width as the stock seal, so I went to Napa and they gave me the SKF seal and its the closest width to the stock seal but the material and construction of it greatly differs and that kinda worries me. I don't wanna pull the motor after installing it cause of this.

 

Not sure if this helps, but somewhere along the line the seal was redesigned...the original seal required a special tool to install, while the replacement is more of a pop-in...this may have something to do with the differences that you're seeing.

 

When I replaced my old rear main a few months ago I ran into the same thing. The new OEM GM seal was about half the thickness of my old one. I asked the guys at the dealership about it and its just an updated version. Haven't had any issues so far with it.

 

sounds like GM has superceded one on us again

 

Hmmm well I think I'm gonna use the federal mogul brand, it slides right in and the design is very similar to the stock one. I have a feeling the napa one requires a special tool to install because it is practically hollow besides the actual seal that sits around the crank, and there is no way to get it in without pressing it.

 

GM 89060436

is the GM seal

 

I was referring to the factory seal needing a special tool...well actually the original style factory seal. From what I've learned though, the redesigned seal does not need a special tool...one of them (either the old style or new style) came with or comes with a plastic installation adapter I believe.

I'd go with the Federal Mogul myself...they produce the factory bearings, so I wouldn't doubt that the make the factory seals also