Diff oil check-Updated

If i have some new crush washers would I be okay opening up the fill on my rear diff and pumping out a sample of the gear oil and visually inspecting it? Then just fill back up with some new oil to top it off and reseal with the new crush washer? I wouldn't have to change it all out if I deem it to be good oil would I? Just want to see if there is any water fouling in the oil.

 

I’ve had to add a missing crush washer for someone after a fresh (dealer) fluid change. Not a big deal to open the fill hole if the truck is on level ground

You can get a black stone analysis of it. My rear was mineral oil clear, the front smelled disgusting like you would not believe. Gear oil can make your garage stink for days. And I've had friends that basically were full of mud, ymmv judging the oil by looks though

 

Unless it’s brand new oil, I’d just dump into a clean pan so you can take a good look at it. A milk jug with the top cut off makes a good inspection container. That way young have no doubts over the condition of the oil after a water crossing. Kind of like developing a baseline. Not that it will be a guarantee the next water crossing wont suck water in.

I might have an unhealthy and unnecessary fascination with seeing how long I can reuse a crush washer. So far I haven’t sprung a leak ever. Although, I’m quite picky about not over torquing and making sure surfaces are clean before tightening. I also tighten and loosen a few times to recondition the washer surface.

 

Nothing wrong with that, just if you’re cracking it open I think you might as well change it if it’s been 10k+ miles.

 

What for unless theres chunks of metal to visually inspect can't tell if oil is really "good" unless you send it in also.

 

If towing, carrying a full roof rack, running over-sized tires or running in hot conditions yall should consider heavier grade of diff oil. Some carry an infrared thermometer tool and check component temps often.

 

You could but a few quarts of amsoil is not much money. Just change it

https://www.redlineoil.com/75w85-gl-5-gear-oil

3 Quarts of this. ^

 

Yeah I think I'll just change em all out. Going to try out the pouch things.

 

https://trail4runner.com/2018/12/24/4runner-driveline-fluids-how-and-when-to-change-them/

This is the way

 

Well I went ahead and changed out the rear diff it had about 7k on it and a lot of Florida water crossings. The breather I put in worked. The gear oil looked like it just came out of the bottle. Just the thinest, like less than 1mm, layer of what had the consistency of moly grease on the magnetic drain plug. I assume this was ultra fine metal dust mixed in the oil, no chunks of metal lol. So it's all good and I can personally attest that the ARB diff breather does indeed work as advertised.