Rear Main Oil Seal on 1998 LS1

**knightryder** · 02-25-2008, 02:04 PM

Hey:
What is the best procedure to change out the rear main oil seal on my 1998 LS1 engine? I had some people tell me that I need to pull the engine. I can't see that. It is really close or do I have the room to pull the bell housing after I get the tranny out of the way.? The information that I have been given is
pro or con.I have worked the older chevys but this is the first LS1 for Me.I have six speed,but I guess

need a little help,Thanks.

**0rion** · 02-25-2008, 02:51 PM

I'll have to look around and see what I can dig up. I've never done a rear main on these cars but I think there's a special tool for it and it's very expensive if memory serves me correctly. I've also read where people have done it in the car without the tool. Let me dig around and see what I can find.

**knightryder** · 02-25-2008, 03:35 PM

Help would most appriciated

**Benner** · 02-25-2008, 03:42 PM

easiest way I found to do it is pull the tranny of course I was putting a new clutch in at the time. The shop I did it at had a puller so it wasn't any big deal.

**Firebirdjones** · 02-25-2008, 04:25 PM

I did my rear main seal last summer.

I pulled the transmission, after that all work was done underneath and very easy to accomplish. Transmission removal and reinstall is the hardest part.

You have to pull the rear plate, bolted to the back of the engine. A new gasket for the plate as well as the rear main is needed.

There is a tool made to help center the rear plate/rear main seal to the crankshaft, but I didn't use it. I found a method that worked for me if you are carefull and take your time.

GM tells you to install a dab of silicone in the corners of the plate where it meets the oil pan. Install the plate and start all the bolts. When bolts are just snug, tighten the lower oil pan bolts first as to pull down the plate towards the pan, then go around and tighten the perimeter bolts. There is also an inch lbs. rating for the bolts, but don't recall without the book in front of me. This worked for me.

**mrr23** · 02-25-2008, 04:28 PM

you don't have to remove the rear cover.

**knightryder** · 02-26-2008, 11:29 AM

Hey Firebirdjones:
Thanks for the info. I really worrying about the seal itself. It has a double lip-one toward the engine and the other toward the tranny. I've talked to other owners and I guess I'm the only one with a rear main oil seal leak. The question I have- will the seal slip over the drive shaft outer collar and maintain the reliabilty of sealing both ways? I'm kind of a old chevy guy. I like the new engines but I really like working on the old engines. Thanks for the help and have a good one. Knightryder

**Firebirdjones** · 02-26-2008, 12:07 PM

Originally Posted by mrr23

you don't have to remove the rear cover.

I did because the gasket for the cover was also leaking

just makes the job easier I think too.

**Firebirdjones** · 02-26-2008, 12:12 PM

Originally Posted by knightryder

Hey Firebirdjones:
Thanks for the info. I really worrying about the seal itself. It has a double lip-one toward the engine and the other toward the tranny. I've talked to other owners and I guess I'm the only one with a rear main oil seal leak. The question I have- will the seal slip over the drive shaft outer collar and maintain the reliabilty of sealing both ways? I'm kind of a old chevy guy. I like the new engines but I really like working on the old engines. Thanks for the help and have a good one. Knightryder

There is a specific way they go on,,,, they have to face a certain way. If you get the seal from GM as I did,,,,it will come with specific instructions explaining exactly which way the seal faces.

I am with ya, I'm old school myself, this LS1 stuff is a little new to me. If you understand the old 2 piece seal stuff for small block chevys and how they have to face inward then you will be able to make sense of the LS1 one piece seal once you have it in your hand. It does have 2 lips on it as compared to the single lip of the gen 1 engine,,,but one lip is designed differently so it's easy to distinguish. Hope that helps.

**mrr23** · 02-26-2008, 02:49 PM

Originally Posted by knightryder

Hey Firebirdjones:
Thanks for the info. I really worrying about the seal itself. It has a double lip-one toward the engine and the other toward the tranny. I've talked to other owners and I guess I'm the only one with a rear main oil seal leak. The question I have- will the seal slip over the drive shaft outer collar and maintain the reliabilty of sealing both ways? I'm kind of a old chevy guy. I like the new engines but I really like working on the old engines. Thanks for the help and have a good one. Knightryder

when you get the seal, it'll have a plastic ring on the inside. as you slip it back on the crankshaft, the plastic ring will push outward. if the inner lip seal folds outward, what i do is take a tiny pick and insert it between the seal and crank and go around it. this helps the seal push back to the direction it needs to go. oil the crank journal to help make this easier.

**mrr23** · 02-26-2008, 02:49 PM

Originally Posted by Firebirdjones

I did because the gasket for the cover was also leaking

just makes the job easier I think too.

well, of course then

**knightryder** · 02-26-2008, 04:39 PM

Hey everybody:
Thanks for the help out there. Sure is good to know thats lot of good help out there and I really appreciate the help. Firebirdjones,thanks for your help also and I will try your suggestions also. Thanks to to everyone and now its time to go to work. Knightryder out.

**Firebirdjones** · 02-26-2008, 05:24 PM

I did as Mrr23 suggested but instead of a pic I use a .010 feeler gauge coated with vasaline so I don't nick the seal. It's the same method I use to rebuild transmissions while installing piston seals, works like a champ.