My 2004 2WD Suburban manual says there is no need to service the differential unless you suspect a leak.

During an oil change at Jiffy Lube they said they topped off the differential fluid because there was a leak and they could service it. I have never noticed a leak and I don't trust them to do that, only oil changes.

My independent suggests differential service at 100k, I have 105k. They remove the cover, drain the fluid, replace the cover and reseal.

So now my question, should I have it serviced or leave well enough alone?

 

I would, and would consider using a synthetic...its not just the lubricating but the additives that make the lubricant "sticky" so it clings to the gears, breaks down.... I think they call it a friction modifier or something like that...

 

jiffy pop only sucks out the fluid and replaces it for like $60 with crap fluid.

do you tow? do you off road?

if yes to either, pop that cover, clean out all the gunk, clean off the cover (brake cleaner works well) dry it all out, seal it up, fill it w/good fluid, and drive another 100,000 miles.

4x4? how often do you use it? the front could use a change while your at it

nevermind you have a 2WD, so no front or transfer case fluid for you...

 

No towing, no off road, just around town and highway. Based on that would you suggest leave it alone? My independent just confirmed no leaks so suggested not to service it.

 

personally i'd do it, I have the tools and parts to do it.

The maker doesn't really care if it lasts you another 100,000.

If you have no leaks, just drain it and fill it... you will sleep better at night...

100k is a lot of miles for some fluid in a sealed box...

I usually change every drop of every fluid in mine at 100k...

Diffs, transfer case, coolant, transmission, I even suck out as much power steering fluid as i can.. why? because it's $4.00 a quart! for a 'sealed' system... it gets dirty!

 

That's my philosophy too. I plan to do the same and change it all out in a few more miles before it hits 100K.

 

friction modifier is something different that what you said it was. It has more to do with trannies and ATF than differentials.

At 100K it is good to replace it if only to ensure the fluid level is fine and you have new gaskets and seals. Replace the axle pinion shaft seal also when you do it. Plus it gives you a chance to put new fluid with new recipes and such. For example, when I had my Lincoln, Ford recommended 80W but I couldnt get it so I put 85W-90 in it. And like 10 years later the dealer I was working at didnt have that weight, they had 75W-140. SUVs made more of the model lineup so a 75W-140 met the specs for the general use of those cars.

 

Not entirely true as the posi-traction additive is a friction modifier. Eliminates grabbing and chattering rearends.

 

i hate chatty rear ends.


if you have the limited slip you need said friction modifier.