TylerH

So i looked under my truck a few days ago and noticed that something is leaking around my diff. From the looks of the oil on the bed, tires and frame i know its not a diff gasket. Im thinking its the pinion seal. So i looked at it more closey and my diff breather was complety covered in oil and corroted. So i pull it off and sure enough it was 100% clogged. Im thinking it was being pushed out by pressure or heat? Anyways i took a picture of the oil. From my experiance it looks like its either over heated or contaminated by water. What do you guys think? I added about half of guart of 90wt. It wasnt very low, I have no choice but to run the oil till atleast tuesday.

And no its not a mc cafe frap....

myyota

Your gear oil is water contaminated and needs to be changed as soon as possible, with that much water in the gear oil you might even have some bearing damage. Change it as soon as possible and keep an eye on it and see what happens.

It would be a good idea to change the gear oil again after about a hundred miles or so to make sure all the contaminated gear oil is flushed out.

skypilot

iTrader: (1)

Its shot; water & mud.

Drain and replace with 10w-30 motor oil (high detergent) and thin so it cleans everywhere. Drain in a day or two after getting it hot (long trip).

I would put in Mobil 1 75w-90 which is in my current repaired diff.

Just so you know, I run 10w30 motor oil in my diffs for over 100,000 miles and only at 310,000 total did I get a pinion bearing failure. So I've done that on my personal trucks. You also get better gas mileage too with the thinner oil.

MudHippy

Motor oil is not gear oil. It's NOT RECOMMENDED to be used as such in a differential. DON'T EVER PUT MOTOR OIL IN YOUR DIFF! That is much foolishness.

Flush it with cheap gear oil. If you don't intend on disassembling the axle and cleaning it out the right way.

dntsdad

Also to add to this, you obviously have a leak allowing water into the differential. Could be a crack (which is what my issue is), a leaky gasket, or water is entering via the breather. Usually the breather is the issue. You can get a threaded nipple to replace the stock breather and run a hose higher so that it will be out of the water during crossings of creeks, etc.

I wouldn't motor oil either, and I doubt that you will see any difference in gas mileage even if that was a good idea.

sb5walker

The diffs require not just gear oil but GL-5 gear oil, which contains extreme pressure additives - suspended particles that provide protection from the shearing force developed by the pinion. To clean the water out, you might consider adding 2 to 3 ounces of Seafoam to a cheap GL-5 gear oil, and run that for a hundred miles or so, before draining and replacing with a good GL-5. The isopropyl alcohol in the Seafoam will leach some of the water out. And you probably should change oil again after 3-4 thousand miles.

And x2 on finding and fixing the leak.

TylerH

Running some cheap gear oil from walmart now but thats what the old looks like. Sorry for the glare. My drain plug was a pain to get off. I had to rattle on the drain plug for like 2 minutes with the impact gun with 15/16, suppost to be a 22mm right? Anyways im going to flush it in about 2 days. that will be about 120 miles.

de'o

what you put into your machine you will get out of it, cheap, it should be clear with a nice blue tint. dont trust wallmart. go to an automotive store

TylerH

Yea, didnt want to spend alot just to run it a hundred miles or so. What oil do you recomend after the flush?

nv4runner

You can also get oil into the diff because of the clogged breather. You drive all day long on the trails and end up getting stuck in a mud hole. Guess what happens to the diff. It cools down and since it can't suck in air from the top it suck through the axle seals. If its water around the axle seals then its water that is sucked in. Next time you heat up the diff the fluid expands and leaks out of the seals, except oil floats on water, so the oil comes out first. I bought a few fittings and moved my rear vent to behind the top of the gas filler neck and the front into a corner of the engine bay. I also added some stone type fuel filters to the ends of the hoses to keep stuff from getting in.

sb5walker

The best is probably Amsoil Severe Gear 75W-90, which is a group IV PAO. Synthetics flow much better in cold weather, and hold their viscosity for much longer. Several of the synthetics are not so great, tho. Mobil 1 and Royal Purple suffer almost as much viscosity breakdown as conventional oils. Red Line performs very well but is a group V ester, and esters tend to absorb water, something you don't want in a gear oil. Lucas is garbage. If you don't want to spend the $$ on the Amsoil, next best is probably Valvoline Synpower 75W-90. Synpower is a group III but performs almost as well as the Amsoil. Valvoline's conventional oil is good too and has very good cold weather flow if budget is a big concern.

Prerun4fun13

yep water in the gear oil

TylerH

Haha yea i just bought some valvoline 90wt. I priced amsoil and it was 16.50 a guart... sheesh thats alot. Even my amsoi quad oil is cheaper then that. Im going to drain the oil tomorow and see what it looks like if its still dirty ill flush it again with walmart oil, if its cleanish ill put that valvoline oil in it and check it in about 500 miles to see the color. Was thinking about throwing some (half quart) or so of atf in there the next flush to help clean it out... Good idea?