Have a 17 6.2 super duty with the manual transfer case. Was cleaning up the interior yesterday and when I finished up I noticed a few drops of oil on the driveway, climb under there and see it's coming from the seal around the rear driveshaft/trans case. Truck only has 110k on it, seems kinda premature but what can ya do other than fix it. Anyone have any experience with doing a seal replacement? Im fairly mechanically inclined so I'd like to do the work myself if it's simple enough. Should also add that I've replaced U joints on previous trucks, just not seals

 

My 17 6.2 was leaking from new, as were a few other peoples. Mine was replaced under warranty so I can't help you other than saying it seems to be fairly common.

 

Generally, those are easy to do, just depends on how deep you need to get into the transfer case. The outer seal is mostly to protect, the inner seal should be easy, both will set you back $50-$60 bucks. Maybe a couple of hours worth of time...if I was doing it I would use that opportunity to replace u joints. Maybe they are still good, but they don't last forever and you will need to pull the shaft anyhow...

 

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I was thinking the same thing about the U joints. Seems like the logical thing to do while I'm there. While I'm sure there are plenty of YouTube vids on how to replace all the various seals, which I will look up, but do you know offhand if any special tools are required? Done enough research to find the drain and fill plug locations and assume draining the trans case would be the first step.

 

Life has taught me that anytime you disassemble any complex device if there is something that might need to be replaced down the road, do it then and keep the old part for a spare.

You should not need to do a full drain, just a little to drop it below the level of where it would come out, on the other hand, if you are draining may be time to just put in fresh...see comment above.

Generally those seals are a press fit, I think the book calls for an hour of labor...

 

There are two different styles. Which one do you have?

 

There is also a slip yoke style as well, but not sure if that is present on the manual T-cases. Would be the easiest seal to change though.

 

Mine uses the flange style seal. Picked the seal up for m my local ford dealer yesterday. Probably gonna try and replace it this weekend

 

I just did this on my 18 with 35k miles. I thought the same thing, odd to fail so soon.

Anyway, I'll give you a play by play on mine.

1. Remove 4 U-joint strap bolts from the Tcase yoke. (12 point ...I think 10mm)
2. Support the driveshaft behind the carrier bearing.
3. Remove carrier bearing bolts. I think 15mm. (may mark position with a marker or such)
4. You should now have enough wiggle room to remove the U-joint from the Tcase yoke, may require a little pry from the yoke. (Be careful not to knock the joint caps off if you aren't changing them.)
5. Use electric tape to tape all the way around the 4 points of the U-joint.... (Keeping the caps on while you move the shaft around)
6. Lower the shaft out of the way. ( still connected to rear axle. Remove completely if you are swapping joints.)
7. Remove Yoke nut with a 1 5/16 socket and impact wrench. (I'm at work, and sizes are off the top of my head. But I think that's correct..... Or whatever the metric version is LOL I used standard)
8. Slide yoke off Tcase shaft.... (Fluid may come out if you didn't drain it... and you should, it's only like 2.5qts of Mercon LV.
9. With favorite screw driver, or seal puller, pry the seal out.
10. Clean seal surface.
11. Open new seal from Ford ($28)
12. Lube seal surface (Tcase and Seal) where it's going to press in. (New seal will have grease on the inner rim to lube the yoke surface from ford)
13. Find perfect piece of exhaust pipe laying around to act as a seal driver.... (or buy the tool)
14. Since we didn't buy the tool, be careful not to cut the seal with your newly built "seal driver" It will tap in quite easily, and once it's already about half way home, you can tap it in with a small ball peen.
**** When we took the yoke off earlier, you should have 4 parts.... Yoke, Nut, Washer, and rubber spline seal.*****
15. Install spline seal on Tcase shaft after lubing
16. Install yoke......washer......nut.
17. Hit the nut with the impact, it will tighten quickly, and you will see the yoke mush down the seal so to speak. So just bump it till you see/hear it get tight.
18. Remove tape after supporting drive shaft back in it's spot.
19. Install Ujoint into yoke (you marked it right? So it will be in the same orientation...Ya, mark it. Hopefully you read this before actual work LOL)
20. Install carrier bearing bolts
21. Fill Tcase with Mercon LV. Mine only held like 2.5qts.
22. Enjoy a job well done!!!

DISCLAIMER!!!!! I do not know torque specs for any of the operations we just did. I just made sure they were all tight. If you need specs, that's on you. I cannot verify, or guarantee your work. If you screw it up, it's on you. I'm only telling you how I did it. Mercon LV is what my case required, yours may be different. Please, just use common sense, this is a pretty easy job for anyone that knows their way around a wrench.

Anyway, I hope that helps. Good luck!

Cody

 

Great write up!

Bolts for U-joint straps get torqued to 46ft-lbs, and the big nut for the yoke at 185ft-lbs if you are into torquing things. I use ugga-duggas

 

As one already said, awesome write up. Info is extremely appreciated. Apparently there is/was 2 types on seals used on the rest output shaft. Mine uses the flange style seal like pictured. Got my seal from the local ford dealer and got a printout of the exploded view as well just ensure the part was correct. Is this the same setup you dealt with?

 

With that many miles on the truck I would drain the t-case and put fresh fluid in. It only holds a couple quarts.

 

Seth, that's what is known as a "slip yoke" style.

Pull the carrier bearing bolts to drop the center of the shaft, and that yoke should slide out of the transfer case. If not, you may need to remove the shaft from the rear axle. But I don't think so. Drain the case first to save the mess. Then just like the other, pry that seal out. Just be careful not to mar up the tcase flange. Then use some kind of pipe driver to install the new seal.... or the actual tool. I have no idea where to steer you for that. But like most seals, I'm certain you could tap it in with a little attention, and finess.

****However, DO inspect the drive shaft slip yoke where the seal rides. If it is damaged, or pitted, you may need to replace that yoke. Most likely not, but it's possible.****

So with yours, no U joint straps, no big nut to mess with. You should be on easy street. Hope that helps. Sorry for the late response, I'm not on here too much. But I was thinkin' about ya, so I checked. Good luck!

Cody

 

Rereading, you said you had a flange style..... No sir, what you pictured is a "slip yoke" style. Just wanted to say that because you may have the wrong seal.

Cody

 

Fair bit of delay on the response here but all the additional posts have been helpful as well. Finally going to tear into it today hoping to finish the project with no issues