Differential Oil Replacement - Every 15k required? (2 Viewers)

[thex2]

I told my mechanic to change my differential oil. He inspected it and "saw there was no water in it" and told me it's a waste of money to replace it. He told me if it was his vehicle, he wouldn't do it. I asked him how often he recommends I replace it then and he said every 30k to 40k miles. This mechanic works on all vehicles and does not specialize in 100-series vehicles. He's a good mechanic and an honest man. I'd like to hear from somebody mechanically inclined on here on whether they agree with my mechanic or recommend I replace it every 15k like the owner's manual says. Additional info that may help: I drive the vehicle an average of 4,200 miles per year. It's all on-road driving. No off-roading or towing a trailer (I plan to start towing a light-weight trailer approximately 2 miles per week).

 

[Dirt J]

My manual only says to "inspect" the diff fluid at 15k but to replace at 30k.

 

[thex2]

My manual only says to "inspect" the diff fluid at 15k but to replace at 30k.

I must have looked at my manual 3+ times, but I didn't catch it until you said that. My manual states to Replace the differential oil every 15k miles, but it has a footnote that states that should only be done if the vehicle is operated primarily in the desert, on dirt roads or towing. Given this new information that I missed, my question is, I don't ever drive in the desert, on dirt roads or tow, so how often should I be replacing the diff oil, if ever?

 

[Dirt J]

I think 30k is fine based on your use. I don't recall hearing off these being rough on diff fluid.

Water crossings (fluid turns to milk magically) would be reason to inspect.

 

[Mike NXP]

30k is fine and most old school folks will just crack the fill, dip a finger in, and if it feels oily and not watery they just move on. If you're feeling eager checking it at 15k isn't a bad idea especially if you're doing water crossing / running hot / tough conditions.

 

[thex2]

Great info guys. Thanks for your help on this.

 

[Wilsil]

Quick and easy to do anyway.
I had neglected it and did check it last month after it was initially done 10 years ago. Oops.
The oil was still in great condition, but good insurance to have it replaced.
It depends on where you take the car as well. River crossings, mud etc and hard off roading will have a bigger impact on it.