Rear main seal install

Jsamps1345 · **Posted:** Wed Sep 28, 2016 11:03 am

Got a couple of questions about installing the rear main seal. When I pulled it apart I forgot to take pictures so I am not sure of exactly how to put it back together. I already ruined one seal by installing it incorrectly. I have 2 tabbed washers that look like they lock into the rear bearing carrier, and the thrust washer.

1. When I put both tabbed washers in only on seems to fit in the carrier. Should I only need one? It's a new crankshaft so maybe this one is shorter slightly?

2. When I put all 3 washers and the rear seal on with the hub, the crank won't turn. Any ideas? I'm thinking I only need one tabbed washer?

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Mountainman · **Posted:** Wed Sep 28, 2016 12:11 pm

There's the part that sticks in the old seal that gets missed, and the flared guide hole of the new seal carrier lines up with it, I think, and then one of those washers sits in against the crank, I think, and the other sits elsewhere. Without the wear marks on the old parts it's more difficult. Maybe staring at the repair manual will help :5SHOTS:

flash7210 · **Posted:** Wed Sep 28, 2016 1:59 pm

Is there a good writeup for replacing the rear main seal?
I'm gonna have to do this at some point :cry:

lacabrera · **Posted:** Wed Sep 28, 2016 3:34 pm

from what I can remember you have to obtain the correct size shims to match the end float of the crankshaft. To larger shims will cause crank to bind, when in your case the flex plate is tightened flywheel on mine. You might be lucky and the shims you removed may go back and give a correct end float as did mine.

Mountainman · **Posted:** Thu Sep 29, 2016 9:22 am

flash7210 wrote:

Is there a good writeup for replacing the rear main seal?
I'm gonna have to do this at some point :cry:

It's easy if you pay close attention to how it comes apart, and you don't lose the piece that hides in the seal when you pull it. Leaving it out causes the crank to bind, and trashes the new seal ($45). Don't ask how I know :banghead:

Jsamps1345 · **Posted:** Thu Sep 29, 2016 10:36 am

Thanks for the responses. The service manual doesnt say anything about these washers. Looks like i will try using only one tabbed washer and the thrust washer and then check the crankshaft play.

WWDiesel · **Posted:** Thu Sep 29, 2016 11:11 am

If you do away with one of the shims, be sure and recheck the end play, FSM says it should be:
Crankshaft End Play
0.080-0.280 mm / 0.003-0.011 in.
Too much end play is not good either!

Jsamps1345 · **Posted:** Thu Sep 29, 2016 11:47 am

Thanks, I was going to check that, if I'm doing this I might as well do it right, don't want to go through this again

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Jsamps1345 · **Posted:** Tue Oct 11, 2016 11:44 am

Alright, I figured out the Rear Main Seal. I mis-installed one of the washers.
From the front of the engine to back:
Tabbed Washer - Rear Main Carrier - Tabbed Washer - Thrust Washer - Rear Main Seal - Flex Plate Hub

Once the new hub bolts come in i can torque it down and see if the end play changes at all. I reused the old bolts at the moment to be able to check it and it looks good at the moment.

thesameguy · **Joined:** Sat Oct 01, 2016 8:24 pm **Posts:** 652

I am about to do this as well...

The FSM says nothing but "pry out old seal, install new seal" - removing the carrier is never discussed, but it does say "scribe witness mark on the block" which implies the carrier *does* come out.

What actually happens when you do this job by itself, engine still in the truck?

Much thanks!

Jsamps1345 · **Posted:** Tue Oct 11, 2016 1:08 pm

If you are changing just the seal, i do not believe you have to take the carrier out. I believe all you have to do is pry the old seal out of the carrier, make sure the tabbed washer and thrust washer are in position and press the new seal in place.

thesameguy · **Joined:** Sat Oct 01, 2016 8:24 pm **Posts:** 652

Good deal - I can't believe how often the FSM glosses over details on the diesels - glad this is not one of those times!

Rear main seal install

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