Anyone know a PN or source for an original style NP208 output seal. Original style has an inner lip with spring and outer lip with spring.

I changed mine to a National 3946 which has a single inner lip with spring but no outer lip with spring. After a couple days it's leaking worse than the original rock hard seal did. The front is not leaking with this new seal, but I haven't had the front shaft spinning. I think maybe there was a reason New Process used a double lip double spring seal.

 

Year, series, wheelbase, A/T or M/T?

 

1986 F-350 Crew Cab 4x4 6.9 IDI originally C6. Transfer case is a NP208.

 

National 3946: I installed one of these for each output shaft.


SKF 18992: NAPA lists this for the rear output, it appeals to be a better seal given teh grooves on the sealing surface would force oil back in when pressed against a rotating shaft on the rear output. On the front output I suspect it may leak more as it would force oil out past the seal. This is an option for the rear seal if I can't find a double lip/spring seal.

 

I cleaned up the original seal and it is a 13905, part number stamped on the inside of the metal sleeve. On the outside it has "outside" molded into the rubber part.

 

E5TA-7A195-TA =

D9TZ-7B215-A .. Input Oil Seal (2 required).

EOTZ-7B215-B .. Front Output & Rear Output Oil Seal.

 

Thanks. That PN is NLA from Ford but I got two off eBay to my door for $20. The question now is if I'm going to use the superior design seal that is not made anymore, do I rebuild the whole case? Decisions...

 

Last MSRP: $17.80 ~ Dealer net cost: $10.68.

GREEN SALES CO. has 33.

 

One of the seal(s) is two nationals stacked I'll have to take a look I wrote everything down

Okay. Here are my notes:

 

This may be my misdiagnosis. Upon closer inspection the speedometer cable was definitely leaking at the cruise control speed sensor adapter which is obviously damaged. After crawling back under the truck to reinstall I noticed some more ATF accumulated under the rear output seal, I wiped it all up with brake cleaner and a rag. Could have been additional running down or could be fmro the rear seal, possible the seat shell to case (which I smeared a thin coat of RTV on). I'll take it for a short drive and let it sit a bit to see if anything else is leaking. It's all dry now so any leak should be obvious if it's coming from the speedometer cable port or the seal.

 

Oil leaks are hard to find sometimes.

 

It was definitely leaking between the metal outer sleeve of the seal and the case. I Had picked up a SKF 18992 the other day just in case, and figured I'd give that a shot and save the NOS seal for a rebuild if I use this case rather than a 1356 for the long term.

Bad idea, I assumed the catalog (Rockauto?) was correct as it appeared the same dimensions as the National 3946. Got it disassembled, cleaned, and ready to install the new seal, slathered it a bit more heavy with RTV, and crawled under with seal and hammer in hand. It was like a hot dog down a hallway, wrong OD. National measures 2.760", the SKF measures 2.706". Quick run to the parts store and got another National 3946, installed, and will let it sit until tomorrow before topping off with ATF.

I also calculated my speedometer drive gear as 15.65 tooth gear to be dead on. If I can find an 8 tooth drive gear for the NP208 (or if my 1356 has one) I could go to an 18 tooth driven gear as a 17.88 would get a dead on reading. My speedometer reads close, but is off by enough to be a slight annoyance, if I can cut the error more than in half and allow room for larger tires that would be nice.

 

Cadunkle is there a name for the little black doodads that go under the nut after you slide the yoke on?

 

A yoke nut seal I'd presume...

NP 208/1345/1356 Yoke Nut & Seal-Broncograveyard.com

 

Works for me