I check mine every October to get ready for winter, and the last 2 years my rear diff.was contaminated with water.(brown runny oil) The first time I found contamination I thought it was from backing to far in the water to launch the boat, but last year I never pulled the boat and the only water I drove in was standing water on I-5 in Portland Oregon during a torrential down pour...I am guessing it's getting in thru the breather which was mounted to the left rear spring above the axle. So I moved it to a cross member in the center of the truck above the axle.
Point is even if it isn't time to change the oil, check it often. I plan to check mine every couple of months till I am sure I got this water issue fixed..

 

how much do the rear axles hold? also, is it necessary to change the fluid in the transfer case, if so what all does that take?

 

Nice Post. Thank you

 

I'm not sure on the axles but the np 271 transfer case takes just under 2 quarts of Mercon V. I changed mine when I rebuilt my transmission last week at 121,xxx and it was black. I used B&M Trick Shift to refill.

 

Really good post with the added pictures. I found that Fel-Pro makes a gasket for the rear diff also - PN RDS55394. I priced it at around $7.00. It could be used in place of the silicone constructed gasket with no down time waiting for silicone to set up. Also the piece of mind in not using too little or too much silicone getting the job done.

 

Sorry if this posted twice.. What type of solvent did you use to clean the mating surfaces? Also why black over ultra gray or even red? Thank you

 

Mineral spirits for cleaning. And I chose the RTV that is "Maximum Oil Resistant". Red is for high heat, which you don't need here. Not sure about the ultra gray. Probably fine.

 

Awesome thank you.

 

I just spray everything down with brake kleen let it dry for an hour soak up whatever sits on the bottom and put whatever gasket maker I have with me at the time on. Bolt it down and pour the oil in. I've run at least 3 vehicles up to 500,000 km this way with never an issue.

 

Just remember:

"Sometimes, 'good enough', isn't".

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