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

Yup... Back in the day....
The guys took 'Shop class'... And the girls took 'Home Economics'... And things went great! You knew HOW TO DO STUFF.
Not so much anymore it seems. Sad.

 

This just sparked a memory for me. I took all the shop classes I could. One yr in auto shop our lazy teacher had us build his demo derby car. With cheats and all. I miss the good old days.

 

Take care of your drivetrain and it will take care of you. Replace fluid at 30K intervals and the drivetrain will last longer than you will own the truck.

My 4Runner had 325K miles on it when I sold it to a business as a parts delivery vehicle.

Everything still worked like the day I bought it.

Or never change any of the fluids and just drive it into the ground. Look how much money you will save in maintenance. Good luck with your truck.

 

I made this sheet metal dust pan in shop class back in the 70s and still use it to this day.

 

My favorite ones are where someone's frame is rusty/rotten and ready to snap in half... And they fill it up with that 'Great Stuff' spray foam and then proudly think 'OK!! Fixed!!' LOL!

 

Your dust pan looks better than my tool box did. lol

 

Well at least its fri, keep it simple you change fluids cause they get dirty ,and cleaner is better, the internet is crazy

 

So much overkill at these intervals.

What do these trucks have, double the rear diff fluid of 5th gen 4runner and the same OCI?
It wouldn't matter, overkill either way for the average owner.

Changed my diffs @ 127K ish. - like new
Same for the TC. - like new

Yep, the oil is cheap(ish), but I don't wash the truck when it's clean just because soap is on sale.

 

The fellas driving around the world know more than anyone! Dusty sometimes brutal conditions.

 

Hey, I took Home Ec! And I enjoyed it. Thats where the girls were, you know. If you thought your GF was safe there, think again. They had other useful stuff, like how to balance a checkbook - remember those?!

 

If only we could use it for every fluid change thread.

 

I did too! A few us friends took it and actually had fun for the most part. I know there are tough guys out there, but it doesn't hurt to learn basics like cooking and sewing a damn button on your pants should it pop off the morning of your interview.

 

I changed mine at 129k, possibly for the first time. Front diff looked surprisingly bad. Transfer case was amber colored but pretty clean. TC fluid smelled like honey not gear oil, so it was probably original Liquid Gold 75W LF. Or maybe it was actually honey. I didn't taste it. Rear diff was moderately dirty, but one of the crush washers was missing, suggesting maybe the fluid was already changed at one point. You could probably change the front and rear once sometime between 30-100k and then never worry about it again unless the fluid gets contaminated somehow. Most of the wear is at break-in, with much less wear after that.

When I changed the fluids on my 4Runner around 90k, the front diff and TC fluid looked new, and the rear diff fluid was dark. Service records suggest maybe it was changed before I owned it, but it's not clear.

The average owner who's not on this forum probably never changes it unless the oil change place or dealer is particularly convincing at upselling them. And similarly, most people with FWD cars probably never change the transaxle fluid, even though the differential in there is doing about as much work.

 

^^^ This ^^^

Make this mistake, and your bullet-proof, 200-500 thousand mile lifetime average manual transmission, and the synchros in it, will start to fail almost immediately, and will be gone soon thereafter. Expensive to re-build, fugetaboutit expensive to replace outright.

https://www.youtube.com/watch?v=3le9ZT5HUlk
< Declined >

 

Continuous revenue.

 

I used to play video games every night after I come home from work, for 2 to 3 hours, but now hardly. Things change, get other things to do, and get out of house.

 

Serious question, when doing the drain and fill on the auto trans, how long do you run, drive the truck between, drain and fills, to get the full 3 drain and fill cycles completed? Ski

 

Why? The more new fluid the better the chance you wash out the clutch packs. Reason, more new additives.

 

The question is being asked due to the fact, if you just pour 3-4 quarts in, then not run, or drive for a bit, no fluid is "mixed" and you just dump the fresh fluid you just put in the pan, and not "swapping out" the fluid. Which is the main reason for drain and fill, changes. Ski