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NP241 and Nv4500 both puking oil

4K views 6 replies 4 participants last post by  EXSwap 
#1 ·
I managed to install new valve cover gaskets over the short weekend and it seems to have stopped the oil leak from the head, however when I park the truck after driving for any period of time, there is a few drops of various pooling up in small areas. The np241 seems to be leaking like a sieve from almost everywhere, and now I have ATF all over my skid plate and underside of the cab. The transmission still may be seeping, from what looks like the input shaft, but it could also be my rear main. There is a few small drops congregating at the adapter plate/block end of the truck.

I spoke with my mechanic today briefly and he told me to check the breather vents on both the transfercase and transaxle to see if mud dobber had made a home inside them. Even if they did, wouldn't I still need to reseal both the transmission and transfercase? If the vent tubes were blocked off, I would assume pressure would build inside the housings of both pieces and wind up blowing out seals.

Also, does anybody have a list of seals and gaskets so I can go ahead and prepare to reseal both pieces of the drivetrain? I've looked around and found nothing but complete rebuild kits, which I'm not interested in doing seeing as both seem to operate just fine.
 
#2 ·
Some of these pictures aren't the best. I hopped under and checked the breather lines, and both seemed to be free and clear of obstructions. I'll have another look this weekend when I can get in the garage and get a proper look at them.
 

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#3 ·
Front should be easy to determine if its the trans or rear main. Not sure about the t-case but mine used to leak between the trans and t-case. I would start by degreasing it all up good and then seeing where its leaking from.
 
#4 ·
I stopped by an O'rileys on the way out from work this evening and checked fluid levels in both. Finger could't find any fluid in the T-case, so I just threw a quart in there and went on my way. The transmission was somehow the opposite and a little overfull, which might be the reason it was slow leaking out of the front seal. I drained the excess fluid, which smelt absolutely foul for only 4k miles, and went on my merry way. This weekend, I will climb underneath the truck, clean the T-case as thorough as possible and wipe it down, then fill it back up to see if I can pinpoint the leak, but from my observations today, it almost looks as if though it is leaking where the case halves mate up and bolt together.
 
#7 ·
Your transfer case won't have a gasket. It takes anaerobic sealer (which can be hard to find in any real quantity). Here's a link to the product:

https://www.amazon.com/Permatex-51813-Anaerobic-Gasket-Maker/dp/B0002UEONM/ref=asc_df_B0002UEONM/?tag=hyprod-20&linkCode=df0&hvadid=312181776237&hvpos=1o2&hvnetw=g&hvrand=10181606411175242990&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9051608&hvtargid=pla-490849814286&psc=1

Most of the time the auto parts stores will have it. No need to use a ton of it, and some will squeeze out. Not sure what the 4500 has in it as far as gaskets go. Overall not a bad job to split the case and reseal. IMHO, if you're going in that far, it's time to inspect all internal parts and replace any seals or parts as necessary. Allstate gear has just about anything you'd ever need and they've always gotten me my parts super fast:

https://www.allstategear.com/NP241-Transfer-Case-Parts-s/1554.htm
 
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