Water contaminated diff oil, without the water? (1 Viewer)

[neal0124]

I've recently rebuilt my front axle, about 8k miles ago. A little while ago I changed out my transfer case oil and decided to check the front and rear diffs also. The rear oil was changed out about 1.5k miles ago when I installed my aussie locker and it looked brand new.

When I removed the front diff's fill plug the oil started leaking out. It was brown and looked chunky, kinda like chunky caramel. I dumped that oil and ran some other oil through it to dilute/rinse the internals out. I re-filled the housing with 75-90 redline (the same stuff I originally put in it). That was about 2 weeks ago. I just went out to check it again and the oil appears to be turning that same brown color again.

My breathers are extended. The seals are good and the birf grease is not getting into the diff housing, the diff oil is also not getting into the knuckles. I have not driven through any water. The gear oil appears to be contaminated with water but I have no idea where it could have come from considering i haven't driven through anything deeper than standing water puddles.

Would a bad 3rd member destroy the oil like this? I've been having an annoying whirring noise coming from the front end and now I'm thinking it is caused by a bad differential and not the ds/ujoints (which I've already had re-built).

Anyone have any ideas for me? I'm now planning on swapping in the replacement 3rd I bought a while ago, I've just been putting it off because it's a pain in the butt.

Thanks for your input.

 

[duggy]

I had the same issue with nasty colored oil and it was because my pinion bearing seal was out. I replaced the 3rd member and all is good now.....but I was also stuck diff deep in water once.

 

[neal0124]

I had the same issue with nasty colored oil and it was because my pinion bearing seal was out. I replaced the 3rd member and all is good now.....but I was also stuck diff deep in water once.

Mine has never touched water/mud more than an inch deep yet.
Did yours leak or make any noise prior to replacing it?

P.S. I like your truck, the best thing about it is the LT stickers on the rear glass. All I have is their sniper sticker and my nightforce sticker. Living in kommiefornia I'm afraid to put a rightwing sticker on my rig.

 

[Douglas S]

In my case, I found chunky water contaminated fluid, so I swapped it out with some cheap stuff and ran that for a week before converting to synthetic.

I also found the source of my contamination to be a cracked vent line, so I replaced that before I did any more water crossings.

 

[duggy]

Mine has never touched water/mud more than an inch deep yet.
Did yours leak or make any noise prior to replacing it?

P.S. I like your truck, the best thing about it is the LT stickers on the rear glass. All I have is their sniper sticker and my nightforce sticker. Living in kommiefornia I'm afraid to put a rightwing sticker on my rig.

Yep, mine leaked very bad. I was going through a quart of gear oil every month or so. Mine also had a very bad whining noise on acceleration at any speed and deceleration at 30mph or lower. Replacing the rear diff fixed it.

If you do not have access to one locally (they are heavy and a pain to ship), you could rebuild it, but I did not bother because there is a crush sleeve you have to torque correctly.

Thanks for the comments on the truck! I went to LT Range Day in Austin, TX and have been hooked on their products since.

 

[neal0124]

Yep, mine leaked very bad. I was going through a quart of gear oil every month or so. Mine also had a very bad whining noise on acceleration at any speed and deceleration at 30mph or lower. Replacing the rear diff fixed it.

If you do not have access to one locally (they are heavy and a pain to ship), you could rebuild it, but I did not bother because there is a crush sleeve you have to torque correctly.

Thanks for the comments on the truck! I went to LT Range Day in Austin, TX and have been hooked on their products since.

Mine is making noise primarily on decel or light throttle, mostly when going over 50mph. I've already sourced out a complete 3rd, it's just a matter of swapping it out now. It's been so dam hot out I don't want to do anything.

I'd love to go to one of their range days. Someday I'll pick up an OBR, but until then I've got a ma-ten that I've built up with a Fulton barrel. I'm also lucky enough to have a private range nearby with steel out to 1k yards to play on. I love watching the impact and hearing the report 2 seconds later.

 

[duggy]

If you plan on swapping the thirds, I would definitely have somebody on hand to lend a helping hand. The shape of the third makes it impossible to use a jack to help you lift.

You can pull the drive shafts out about 6 inches or so to free them from the diff, but I would also pull the driveshafts out for a full inspection to see if you have any twisted splines. I also put a small bead of RTV around the third and the drive shaft flanges to ensure no future leaks spring. Let us know if you run into any issues! This is a fairly straight forward job.

 

[neal0124]

I bench pressed the rear 3rd out and back in by myself when I installed my Aussie locker. That was real fun. The front diff is smaller/lighter so I'm sure it will be much easier than the rear. I've rebuilt the front end so I know what I'm in store for, I'm just lazy and don't want to work in the sun anymore. Thankfully it's only supposed to be 80 degrees tomorrow. Last week it was just under 100 and there was no way I was going to dig in and make a huge mess in that.