5.4L rear main seal question

[mkc1962]

Got transmission out yesterday, rear main seal housing removed, new seal and slinger installed. And Transmission back in....now to spend fathers day getting all rest back in. On the original main topic of the SLINGER? like so many finds I dont see its purpose other than maybe a way to keep any debri from gaining access to the rear main. The slinger firmly mounts to the body of the crankshaft but they freely spins within the rear main seal housing. The rear main itself is a very loose fitting 1 seal surface seal. The type of seal that a small amount of anything could cause pre-mature failure. Do they make a diff type of rear main seal that is a dual seal stiffer type, dunno couldnt find one went with OEM. Only way I would leave the slinger off is IF I were to be able to find a more rugged looking rear main seal. My pic attached of the rear main you can see the single lip configuration.

 

[08T1]

So not much to it. Thank you for sharing.

Good luck with your project. Have a good one.

CJ

 

[mkc1962]

Should anyone follow this thread in the future. DO NOT buy a 4503N seal for a transfer case output shaft. ( rear main drive shaft) This is a two part seal, dust and oil. The dust is way too tight, a short amount of mileage will cause extreme heat to the rubber and the entire seal will pop out of the housing. Luckily I caught the cloud of smoke coming from the back of my expedition as the xfer case fluid was slung onto the hot muffler almost instantly. I was able to remove the dust seal as by time I got to it, it was near a molten goo. Was able to reinstall into tail housing and using only the fluid seal finish the trip. I have ordered OEM from Ford based on VIN. Ironically the cross ref to aftermarket is in fact the National 4503N. As for the national must be a quality issue.

However, after 800 miles, and towing a tandem axle trailer, happy to report no more rear main seal leak.

 

[08T1]

Thanks for all the pics and updates.

CJ

 

[MattP1976]

I know it's an old post, but did you have any issues removing the old rear main? Did you first remove the retainer plate? I took the plate off, but the rear main seams stuck to the crankshaft.

 

[MattP1976]

Disregard. I figured it out.
: )

 

[TB8715]

Old Post so I hope you can answer. What year was your Expedition? I have a 2013 that I am sure has a rear main seal leak at 85k. Do I need the Xfer case seal? Can I pull the trans without removing the Xfer case? How long did it take?
I appreciate any help. My friend is a BMW mechanic who can help but has no clue on this one from Ford.

 

[riphip]

Since it has to come out, replace it while the fluid is out.