typical "life" of differential oil?

[TexasTea]

hi guys, my truck got hit by a flood over 3 months ago now and prior to inspection, i assumed the worst, water in all orifices.

money was extremeley tight so i was relieved yet disappointed when i drained the differential on my 04 silverado (2wd) to notice that water had not contaminated the system. At 150,000 miles the diff oil was ready for removal anyways. I got the truck at 70k so who knows if it had been done at 50k like the maint. schedule prescribes. (i did notice that the magnet was not hairy and looked to have a moderate amount of fine particulate no big chunks or anything so i assume it had been changed at least once in its life)

that being said, i changed it out with super tech 75w90 syn-blend gear oil.

I have been reading online that people change this out after 1-2 years max.

I am the type of guy who believes if it aint broke dont fix it, GM requires a 75w90 in the owners manual so can i keep this in here for another 50-75k miles?

obviously there was no interval on the bottle of fluid itself, if the oil is used up after only 15-20k i have no problems changing it i just want to know.

 

[Lyman]

Some makes recommend every 100k miles. I like to change diff fluid every 50k. Sooner if I cross any water.

 

[Jimzz]

If it has a limited slip diff and/or is used for towing then every 30-60k.

For most others with open diffs or only do very light/not often towing then every 100k.

Best to start by checking the owner manuals and forums online as some diffs are more sensitive to older gear oil. I know the original Nissan titan it was good to change it every 30k due to many diff issues with them.

 

[Gene K]

Every 30,000 miles for severe duty (like towing) or 100,000 miles for normal duty.

 

[abycat]

Originally Posted By: Gene K
Every 30,000 miles for severe duty (like towing) or 100,000 miles for normal duty.


id say 30k severe and 60-70k normal but I don't think 100k would hurt anything. Unless the manufacturer says sooner or if water gets in. my vents are about 4' off the ground so I'm kinda lucky there.

 

[Taildragger]

Someone say "water in your dif"?

 

[barkingspider]

I have the same supertech 75w90 in my 04 silverado rear diff. I don't think I will ever change it again. No severe duty. And I'll sell it before I put another 50K miles on it. You are good for at least 50K to 100K miles normal driving.

 

[Shadwell]

a little oil in your diff water......

 

[Chris142]

I ran torco gear oil in my Jeep.it lasted 55k then started foaming and blowing out the vent tube.

 

[Bud_One]

I say it depends on the vehicle and use.
I purchased a 1991 S10 Reg Cab 5speed with the 2.8V6 back in 1995 - with 52k miles.
Passed it on to my dad at around 70k miles a year later.
He drove it until the heater core gave out for the 3rd time and it had 217K miles.
A/C still worked when he sold it - still had R-12 freon.
He would overload that poor truck like crazy , used it often to haul the old shingles from roof jobs he did.
One load was 1.1 tons of old shingles.
He never serviced the differential and I never serviced it.
How it survived - I have no clue.

 

[artificialist]

In some cars you get away with ignoring gear oil for 200,000 miles, in others, you have to do repairs at 80,000 miles if you ignore the oil.

Maintenance schedules vary based on numerous factors. The first things that come to my mind are the oil capacity and the expected temperature of the differential.

However, other things may be involved. Mom's 2005 Jeep Grand Cherokee called for the first gear oil change to happen at 12,000 miles, a number that I think is crazy.

 

[Jeff_in_VABch]

Taildragger - nice job!

 

[CBR.worm]

My experience has been that after the first change, the oil will last a long time under normal use. I recently replaced gear oil in a 140k mile vehicle that had only been in service about 25k due to water concerns. It looked exactly as it did coming out of the bottle. Luckily, no water.

 

[Ducman]

Originally Posted By: artificialist
In some cars you get away with ignoring gear oil for 200,000 miles, in others, you have to do repairs at 80,000 miles if you ignore the oil.

Maintenance schedules vary based on numerous factors. The first things that come to my mind are the oil capacity and the expected temperature of the differential.

However, other things may be involved. Mom's 2005 Jeep Grand Cherokee called for the first gear oil change to happen at 12,000 miles, a number that I think is crazy.


IMO, not so crazy at all.
I wonder what reasons would prompt one to say it's crazy????

 

[Ducman]

Originally Posted By: CBR.worm
My experience has been that after the first change, the oil will last a long time under normal use. I recently replaced gear oil in a 140k mile vehicle that had only been in service about 25k due to water concerns. It looked exactly as it did coming out of the bottle. Luckily, no water.


This is right.

Regarding the OP'S thread starter.
A lot depends upon many variables.
Service duty is critical and plays a large part in the life of the fluid.
Likewise the design limitations of the unit are critical along with the quality of the fluid.

Water ingress will obviously change the equation for the worse, also poor attention to cleanliness when performing a routine fluid change at normal service intervals will shorten the life of a diff as a bit of dirt will destroy the crown and pinion.

Some manuals have rather good service information based upon service duty and distance.
Other manuals simply state the diff is "filled for life" with no further reference to any other information, and the only way to get any further information on service refill/capacity, Approved oil brand and grade, required additives, etc is to contact the dealer.

Depending upon the vehicle I have dropped out fluid that looked and smelled perfectly fine even after 200,000-300,000 kms and would've happily left it in there for the same distance again. By then the vehicle would most likely be long dead and buried. Certainly in this case it would justifiably be classified as "filled for life".

Other diffs have been totally destroyed by being used in an overdriven state well inside of warranty on the factory fluid.

 

[B320i]

Back in 1993, my BMW had a recommendation for about a 50,000km service interval for the differential - or about every second Inspection service.

The only exception to this was if the vehicle was used for "seasonal towing" after which the transmission and differential fluids were supposed to be changed - presumably in assumption of additional stress on these two components that may have degraded the fluid due to temperature or additional wear.

In theory, it is no different to exchanging fluids on a vehicle that went for an expedition in the water. Boils down to what the vehicle was 'designed for,' as opposed to its actual usage.