Seems I got the wrong part from Napa when I was explaining it, and the FSM makes no mention of this thing's existence... but what the hell is the VERY outer seal (right behind the u-joint) called?

Does it even exist? All I found where shards of what appeared to be an old seal/dust cover.

Can it be found on Napa's website?

 

It's just a dust shield. Not really all that useful, as it tends to trap stuff IN the axle..... I wouldn't even worry about it.

 

I believe this is what you want, National part# 5778. Or go to Quad4x4.com. http://quad4x4.com/Dodge%20Frt%20Axle&Steering.htm


BTW, it would be nice of you to put all the info about your truck into your sig.

 

its also called a "slinger".

i also recommend you NOT put it in, as it traps mud in, rather than allowing it to wash out. the actual seal is at the inner end of the tube. the slinger is useless.

here's a pic. this site is pretty expensive. if you're set on replacing it, look elsewhere for better pricing.
http://www.riversidegear.com/4x4-fro...94---2001.html

 

i'm going to disagree on National 5778 as the slinger. i see that as the pinion seal.
http://www.superioraxlegear.com/seal...8-p-15180.html

 

https://napaonline.com/Catalog/Catal...+50022+2022009

That's a pinion seal. It sort of looks like some of the pieces I found, but not really like what's on the other side.

Is it really that important then? To be clear, it is the very last "seal" on the axle tube.

It's for a dana 44 on my 1500 btw.

edit:
Outboard Axle Shaft to Axle Housing Seals looks more like it. Replace or screw it?

 

screw it.

 

I had hell finding one too when I did my u joint. On phone now, but ill get the website I got mine from tomorrow, $13 I think.

 

Dealership didn't have it, would have to order entire axle assembly to get from them. The last link from squarebit was it.

 

Listed on Rock Auto, NATIONAL Part # 5778 More Information About this Part Oil Seal; Polyacrylate Seal, Shaft Size=1.552", Housing Bore=3.16, Outer Diameter=3.165, Width=0.53in
Front Axle; Outer; Spicer 44-3F 8.5" R.G.