Mechanic checked it out. He moved the rear plug/screw and water/diff. fluid leaked out. He stated that it happens since there is a small hole and water gets in if you go off road and into deep water. Does he speak the truth? Any how I'm off to the dealer for more differential fluid unless someone can tell me there is a better place to get it from.
All comments are welcome.

 

There is a vent on the diff but it should have a hose on it that vents it about a foot above the diff. Check, yours might be missing. But even with the hose gone it would be hard to get a significant amount of water in there unless it was submerged for a period of time. You can gear oil for it at any auto parts store. There is nothing special about and I definitely wouldn't get it from the dealer. Any 75w-90 will work. I use a good synthetic but it's really not required. I change mine every year because I do a bit of off-roading. If yours doesn't leave the pavement you could do it every 2 or 3 years.

 

Hey Krazz, my mechanic had 80w oil NON synthetic. In your opinion is that good enough or should I search hi and low for the 75W synthetic oil?

 

You can use 80w dino if you wish. It certainly won't harm anything. Synthetic is the best way to go though. Its best to find an oil with a "range" 75-90W instead of just 80w. It will better suit the differential in varying temps.

 

80w would probably be fine depending on how you drive. I drive it pretty hard so I like to give it the good stuff. I also change it much sooner than the factory recommendation.

 

Thanks for the feedback men! One quick question how much should I purchase if I want to change out both differentials. I know its hard to get out all of the fluid, but how much can a person realistically drain out?

 

I believe it all comes out when you drain it. You might be confusing them with automatic transmissions, where only about 1/2 of the fluid comes out. I want to say its 2.5 quarts a diff.... I can't really remember. I bought something ridiculous like 8. Its better to buy more than you need. You can always use the leftovers later.

 

Yes almost all of it drains out and I think I used somewhere around 2.7 per diff so if you got 6 quarts you should be good.

 

Thanks guys! I will be taking care of this project asap! I hope I did not harm anything by waiting this long to change out the gear oil.

 

You should be ok if there was more diff lube than water. Diffs don't get all that hot really, so the lubricant isn't quite as stressed as in other components. They are also pretty strong and simple.

You can get almost all of the fluid out through the drain port. I like to take a quick drive to build up just a little heat and get the lube circulated, then drain. But that's not something you have to do. If you wanted to get every last drop out you have to drop the cover - but then you'll have to do a new gasket and it's more work for not much benefit, so just drain it until it stops dripping.

Then go to the parts store and get the gear oil of your choice. I use Lucas HD - I run the same stuff in my Jeep that gets a lot of off road abuse, and my Rangie sees a good bit of off roading too, so I just buy it in bulk. Then, while you are at the parts store also get a small pump that screws on to the top of the bottle of diff fluid. These are cheap, like $10 and will make the job quick and much less messy.

After you get the pump hooked up to the bottle (and have screwed the drain plug back in obviously) just put the tube from the pump in the fill port up top and start pumping.

The guys have it about right, mine takes just shy of 3 bottles - so if you are doing both buy 7 so you have an extra in case you somehow spill a bunch. Keep pumping it in until the fluid starts to come out of the fill port you are pumping the gear oil into - then it's full so hurry up and get the plug back in.

I do mine annually since I do off road and it sees some mud and water.

This is an easy DIY, you'll get the hang of it and it will be a 15 to 20 minute job per axle.