Why is it recommended to change differential and transfer case fluid every 30k miles?

Shavings will happen with your first change.

I’ve seen differential fluid turn black after less than 10,000 miles, I don’t necessarily think the color of the fluid is an indication of how used up it is.

 

It’s often the second owners that face the consequences of lack of standard maintenance. Sorry that happened to you guys. As a former tech I can attest how frequently that happens. Often second hand owners would take their vehicles in after buying them for inspection. It was pretty common to see oil that hadn’t been changed in 20,000 miles. Original spark plugs on vehicles with 200,000 + miles. Severely damaged ball joints, etc. people would be amazed if they only knew how many other drivers are driving around in vehicles about to catastrophically fail. Lack of maintenance is more common than people who are OCD about it.

 

Agreed, same goes with engine oil. what concerned me was the thick layer of metal silt when the fluid settled. Like thick enough for flatfish to live in..

 

I've only got 12,000 miles on my truck but am probably going to change those fluids early simply because those shavings floating around in there make me nervous.

 

Thanks. I felt really bad I did that to my girlfriend's "new" truck. But she didn't fire me and we drove the truck to 275k miles and had until just a couple years ago so happy ending. Though, it was an expensive lesson learned.

I've always wanted to know what happened to that missing oil in the trani and why the diff fluid would have been so low? If someone drained then forgot to refill the trani, that doesn't explain why the diff fluid wasn't bone dry as well.

I'm sure as a former tech, you've seen some wild and crazy stuff.

 

Exactly. And there is no such thing as 'Too Much Maintenance'...
I for one, am gonna get a 500k mile Tacoma.

 

I did my plugs at 100k
Trans fluid and front and rea diff also over 100k
Everything especially the plugs still looked good!!

 

I used 75w Ravenol for my TC. It was (+-?) $25 a quart. Took me a minute to figure out how the get the goofy German top off, but.... Comes with a pull-out spout. Very easy refill.

 

Oh, I absolutely believe how many morons out there do no, or next to no, maintenance on the rigs. Watch some episodes of 'Just Rolled In' on YouTube. Whats even more terrifying are the ones who try to fix things themselves (Or have their idiot brother-in-law try) with bubblegum and band-aids and end up limping some rig into a shop to find it has been completely destroyed.

 

Good thing is, there is magnetic drain plugs for the F/R differentials and transfer case from the factory.

 

U just introduced me to 'just rolled in'... omfg!!! Cringe! I know the general public can b dumb but...

 

Too much maintenance will take out an automatic trans early.

 

Yes and no.
Full flushes can be detrimental.
Regular drain and fills can help maintain the life of the trans.

 

OK, we'll see who's truck lasts longer...

 

Any of y’all done oil analysis on these parts? I’m betting 30k is much more often than required.

 

I am glad people like you exist, because otherwise I’d have a much harder time buying a quality used car. Plenty of perfectly good used cars out there, however being in a shop I know you see the worst of the worst all the time.

 

And don't forget for when that time comes, that the Manual gearbox NEEDS GL4 fluid and GL5 should NOT be used.

 

Rule #1 when buying any used vehicle. Change all the fluids immediately, that way you will see what you got from the get go. Personally if I m looking at a vehicle, will check fluids before I buy.

 

This 110%.
When I was a kid I ruined a silky shifting 5 speed in my 88 SR5 by putting GL5 in it. Never shifted the same……even after switching back to a GL3.

 

30k miles doesn't seem too crazy to me. That's like every 6 years based on how often I drive it. Lol So maybe $10-20 a year or so.
I changed both diffs and transfer case after first 2k miles on the new truck and as expected diffs had shavings and were surprisingly dirty looking for such low miles.
Using Ravenol also for both diffs and tansfer case.