How often change Differential fluid?

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I have 1994 Montero SR 3.5 DOHC. I am original owner and it's garage kept. I 've always changed the diff fluids every 30,000 miles. The owners manual doesn't mention the diff fluid, except for specs. When I had it done at the Stealer, they told me that they don't service the diffs unless there are problems. I'm OCD I guess.....What are your opinions?


Respectfully,

Pajero!
 
For the dealership, there's no profit in a drain and refill of a couple of pints of diff fluid but there is for a repair. Differentials often go the life of the vehicle with no checks or maintenance of any kind.

I change the Red Line in my 03 V8 4Runner 2x4 every 30-50K when I think about it. At 160K+ of desert driving and towing there's been no noise or any other indication of a problem.
 
30k seems very frequent unless the truck is constantly being used in extreme conditions.

OEM recommendations are kind of all over the place. Some claim lifetime, as you said -- which I interpret to mean "warranty duration + 1 day". Some OEMs make it easy by saying "every 3rd/4th/5th/etc oil change" which makes it easy. Others just stick to "every X years".

Here's my two cents: pay for an analysis and see if the fluid is getting contaminated, breaking down, etc, and then adjust your intervals from there. I suspect that a 30k interval is pouring good fluid down the drain unless those diffs are notorious for destroying gear lube. As anecdotal as this is, but my old BMW M3's rear differential had the fluid changed every 3 oil changes and it was still fine (which included hard driving on a race track).
 
On a new vehicle, I dump the FF at 10K miles or so. The majority of the wear happens very early in an axle's life. You can then extend the OCI out quite a bit from there, even with towing. To get an idea of what I mean take a look at the UOAs of the rear axle in my retired 2010 FX4; note how much iron was generated at the first OC, but less and less per mile even though the subsequent OCs were run much longer.
 
^^^^^^This^^^^^^ I've changed out the FF on my new rear gear differentials OR first thing on any used one. RedLine is my choice also.
grin.gif
 
I agree with the above. An early change (10,000 miles or so) the get the initial wear metals and such out, or first thing when you buy a used vehicle.
After that, "regular" use is 50,000 miles or so, if "severe duty" (off roading, water crossing or submersion, frequent towing/hauling etc), then more often, how much more varies depending on use (like a long water submersion, ASAP).
 
Dodge Lifetime warranty requires every 15,000 miles with Synthetic 75w90 which is insane. It looked bad the first time grayish and ugly after that it's a waste of oil and money. Comes out golden and new. I think one early change and then every 100,000 if using a top name synthetic.
 
I (embarrassingly) just changed the diff fluids on my LR3 for the first time this weekend - 160k miles and the fluid wasn't terrible. Put in Mobil 1 75w90. Still brown. I change the diff fluids in my Liberty every other year (or 20-30k miles), as I wheel it so there's a chance of water getting in. I don't use synthetic in it.
 
I do one early in the vehicles life. Less than 30k miles. After that on a 40k mile interval, at least for my Silverado. I always do front and rear at the same time.

Transfer case before winter every year.
 
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I agree with above, changing the initial fluid early after break-in. It usually comes out looking like metallic paint. Afterward, changes aren't as important, especially if synthetic fluid is used.
 
These days Mitsubishi have 45,000km for gearbox and transfer oil changes, and 60,000km for final drives. Or half that for severe service.
 
I think I changed it at 20k on my new F-150. Ford says 150k.

The fluid isn't filtered after all. I read something on the 'Net about differential whine for F-150s. Final reason is psychological:at 20k it feels like maintenance; at 150k it feels like unscheduled repair.
 
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If you are hardcore enough to have a snorkel, I'd say differential maintenance is pretty important !

Do you do water crossings ?
 
I suggest you maintain your 30,000 mile service intervals for both differentials. I drain and refill mine every 40,000 km (25,000 miles), which is compliant with what Mitsubishi recommends for their severe service schedule in this part of the world. I stick with synthetic 75W-140 (primarily Motul), but in your climate conditions a quality synthetic 75W-90 will suffice. Make sure you service the transfer case as well.
 
Myself, I would only change it if the differential got into some high water or if it had to be opened up for repairs. I have yet to experience either and never had problems with probably the best built component on a vehicle.
 
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