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Rear main seal ?

NoInterstates!

NoInterstates!

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Mulvane Kansas
I recently finished a good amount of work on my truck including R2 the rear main oil seal. Seemed great for a a while. Now clutch chatter is back worse than before and my bell housing is wet with a few drops here and there. I think I lost 2 quarts of oil in about 1000 miles. You can put the rear main seal in backwards can't you? If anyone could give a little rundown on R2 that seal maybe I can do it right this time. The learning curve is like a tire iron in the face this time. Oh well, I will be prepping to get the Trans/Xfer case off again. Also, On a crew cab, you know the cross member that holds the back of the tranny up? Mine is setting on top of the bottom frame rail with the bolt spacers on top of it. I was wondering why such an odd configuration for that. My torsion bars bump on that crossmember sometimes. I put it back the way I found it, but I think it may have been wrong. If someone could post a photo of how thier crossmember is configured I would sure appreciate it!
 
NoInterstates! said:
I recently finished a good amount of work on my truck including R2 the rear main oil seal. Seemed great for a a while. Now clutch chatter is back worse than before and my bell housing is wet with a few drops here and there. I think I lost 2 quarts of oil in about 1000 miles. You can put the rear main seal in backwards can't you? If anyone could give a little rundown on R2 that seal maybe I can do it right this time. The learning curve is like a tire iron in the face this time. Oh well, I will be prepping to get the Trans/Xfer case off again. Also, On a crew cab, you know the cross member that holds the back of the tranny up? Mine is setting on top of the bottom frame rail with the bolt spacers on top of it. I was wondering why such an odd configuration for that. My torsion bars bump on that crossmember sometimes. I put it back the way I found it, but I think it may have been wrong. If someone could post a photo of how thier crossmember is configured I would sure appreciate it!
Click to expand...


Put the spacers under the cross member, I went through the same thing with my truck. They run fine with the spacers under the cross member. Better drive angle. As far as the one piece rear main seal, use grease on the lip of the seal that rides on the crank, do not use any sealer or lube on the outside of the seal when you seat it in the bore of the engine block.
 
Thank you Slim Shady

Thank you so much for your reply.

Is your crossmember above or below the bottom lip of your frame? Mine is setting on top of the bottom frame lip,(aka it can sit there holding up the back of the drivechain without the bolts.) Is it supposed to be under the frame with the bolts holding it up?

I have now also read that you can push the rear main seal in to far which will cause the oil to leak. I pushed mine all the way in, bad move apparently. Does the rear main seal have a front and back, I think I may have put mine in backwards!

I have to fix this, a vacuum pump, APPS, and an AC pump coil before we hit the ALCAN highway in June. Wouldn't be such a big deal, but all my tools are packed. What a nightmare. Will get it done though, no choice!
 
Seal orientation, location

Yes, most seals should have the lip towards the fluid being retained. If memory serves, the 6.5 rear main has a spring inside that lip to put a little tension on the seal towards the crank. The solid/flat side faces out.

And yes, that seal can be put in too deep.

The 6.5 is the first engine I actually got the installation tool (used, ebay, see pics) to put the rear main seal in. Typically you can get the seal tapped in squarely with time & light hammer/punch taps, but I found the 6.5 seal tough to get in squarely that way.

The installation tool screws onto the crank. Then you spin the T-handle which squarely presses the seal in until the tool bottoms.
 

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CDR - oil seeps, leaks in general

It's also worth checking CDR function when dealing with oil leaks. Turbo engines under boost tend to have more blowby. The CDR system is designed to pull a little vacuum on the crankcase. That helps to eliminate any crankcase positive pressure trying to push oil past seals, gaskets, etc.
 
I got to be missing something?

When I put in the seal, I was able to slide it on with my fingers. It was just a rubber ring with a spring IIRC. Is it supposed to have something that needs to be driven in like the front crank seal in the timing cover? I didn't have to hammer anything. I just pulled it out with a dental hook and slide a new one from NAPA on with my fingers!
 
Something is wrong there, probably sold you the wrong seal, it should have to be drove in unless you really ate your Wheaties. IIRC, that seal is suppose to be slightly below the block surface, like .030", the tool mentioned will put it to the correct depth. If no tool, I'd put it flush and square to the block should be fine as long as the crank aint to rusty or grooved.
 
NICE!

well I wonder why it leaked before and after now! Like expecting a tire to stay on without the lug nuts. When I R2 it, I gave it a long hard look and wondered if it was that easy, Like thats all that seals it, no wonder these things leak!
 
Yeah, the seal should have an internal metal frame, similar to the front seal you mention, 'cept bigger diameter.

Also, be careful not to nick the crank while digging the old seal out. Check the crank surface where the seal rides for any burrs, corrosion, or roughness. If there's a burr, that surface needs to be smoothed. Or it will abrade at the new seal & go leak again.
 
I used the GM tool pictured and it sets the seal a little deeper than OE one. Suppose to be so if OE wore a groove I think. The tool works like a champ.

Use clean fresh motor oil to lube the seal. Start with clean surfaces then wet the OD and ID with a light coating of oil. I think I used Felpro brand.
 
If your seal (new one) just slid in, there is a big issue.

I have never replaced one of these in the rig but have done a few during engine O'Haul
I place the seal on the crank and slide it in so its flush, square it up and then install the main caps and complete the bottom end.

The seal has a large ridge around the outside ring that compresses when installed.
The seal could be installed backwards but it would be tough.

The inner lip points towards the inside of the engine.
Keep the outer edge flush with the block housing and you will be fine.

Every seal I have used looked just like the original so if yours slid in easily there had to be an issue somewhere.

Take a picture or 2 of the rear of the engine and the seal you removed as well as the new one and post them.

We may be able to help diagnose better if we can see what your working with.

BEST

MGW
 
like others said,that seal needs to be tight in the outerbore, if you could pull the old one out with a dental pick things where to loose, If the bore is over sized ( i had that on a 6.2 once)You may have to hunt for a diff brand seal or one that has a slightly bigger OD to get a tight fit. Gluing it in may or may not hold.
 
Hey All

Living in the camper now waiting to head down the ALCAN. Dont have any real Internet. I wanted to put a post in here. I went to the dealer and got a seal from them to see if it was different that the one at NAPA. I see where you all are coming from now. Bottom line, the one from NAPA is garbage. Its half the size of what you all are talking about and its all rubber. I pulled the old one out with one smooth pull with an awl. The napa one was what was in mine, and its what I put back in. No wonder it leaked before and after! Learned hard this time, but you know they say what doesn't kill you makes you stronger...well I'll be stronger after lifting that Xfer back up/down and re-torqueing everything! Shame on NAPA/FELPRO though. Take care all and watch those NAPA seals!
 
I wouldn't blame napa or felpro. The dummy that looked up the part is the problem. Felpro makes the correct seal.
 
NoInterstates! said:
Hey All

Living in the camper now waiting to head down the ALCAN. Dont have any real Internet. I wanted to put a post in here. I went to the dealer and got a seal from them to see if it was different that the one at NAPA. I see where you all are coming from now. Bottom line, the one from NAPA is garbage. Its half the size of what you all are talking about and its all rubber. I pulled the old one out with one smooth pull with an awl. The napa one was what was in mine, and its what I put back in. No wonder it leaked before and after! Learned hard this time, but you know they say what doesn't kill you makes you stronger...well I'll be stronger after lifting that Xfer back up/down and re-torqueing everything! Shame on NAPA/FELPRO though. Take care all and watch those NAPA seals!
Click to expand...

Unless lifting that xfer back up/down and re-torquing kills you, this will hold true.

I had a NAPA crank pulley from china fail 1 month after install (if it ever wasn't failed)...

Bottom line, everyone is buying the cheapest available parts to sell to the customer for the lowest price. Unfortunately this always results in cheaper quality.

Can't blame NAPA, no, but this seems to be a world-wide trend that is really bad news.

What will happen if AC-Delco stops making parts.... And we all know, they don't get nearly enough sales because their prices are high, but nobody complains ever about the quality of Delco genuine parts.

You get what you pay for most of the time this is true.
 
Thanks for posting this. I am getting ready to rebuild my 6.5 The seal that was in mine is like the one you discribed. I could just pull it out easily. Mine did'int leak though.

Are the seals that are supossed to go in there like a rear wheel hub bearing on our trucks? 14 bolt FF. as far as having a metal casing?
 
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Burning oil said:
Thanks for posting this. I am getting ready to rebuild my 6.5 The sal that was in mine is like the one you discribed. I could just pull it out easily. Mine did'int leak though.

Are the seals that are supossed to go in there like a rear wheel hub bearing on our trucks? 14 bolt FF. as far as having a metal casing?
Click to expand...
these are the best, but it depends on the kit,some have them,others come with the rubber OD
Click to expand...
 
bison said:
Burning oil said:
Thanks for posting this. I am getting ready to rebuild my 6.5 The sal that was in mine is like the one you discribed. I could just pull it out easily. Mine did'int leak though.

these are the best, but it depends on the kit,some have them,others come with the rubber OD
Click to expand...

Thanks , I got my total rebuild kit yesterday, but have not opened the boxes yet to see what the seal looks like.
Click to expand...
 
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