about differential and transfer case fluid replacement

Nope! Old woves tale. Your likely long over due for service, and because of that there could be some abnormal wear of internal components. Clean lubricant is what is necessary to protect moving parts.

I am strict about meeting specifications for my vehicle's lube. For instance Mopar spcifies AT4 for my toad's transmission. Since most of the AT4's cost about the same I use genuine MoPar fluid. Quicksilver's transmission and auxiliaries are Fuller Road Ranger. Fuller specifies 50 weight mineral oil for all three boxes. The SQHD axles want a specific spec gear oil. Ditto. The Stemco wheel bearings also specify mineral oil.

Same for filters. Cummins approves Baldwin filters so the engine gets a B88 filter. Same for the C750L Luberfiner bypass filter. Fuel filters are a pair of RAcor's. I chose the 1-micron S elements.

Maybe I'm too picky. After all, ALL TIRES, have to meet federal specs so what's the difference? Engine Oil? Both Delo 400 and Shell's Rotella T have earned good reputation among truckers for a reason.

I got carried away changing ATF fluid. Dropped the pan three times on the toad. Got the sniffles at the cost of the transmission fluid. The tears dried instantly when a priced a reman MoPar transmission.

thehippie wrote:
My 4Runner 4wd is already 122000 miles and differential and transfer case fluid not changed. It still drives like a dream.


I heard that if you change the fluid it will hurt your car more since those fluids never been changed since.


Is that true?

You've confused these fluids with automatic transmission fluid advice. After a lot of miles many people feel that a fluid change in an automatic will break crud loose and cause problems. A differential and transfer case work much differently than an automatic transmission and there is no danger whatsoever.

Do it, you car will appreciate it.

If the fluid change causes trouble then you were about to have trouble anyway.

Having said that I don't recommend heavy maintenance right before a big trip. Do the maintenance at least a week before and drive it a bit.

Differentials and transfer cases take hypoid oil. I change mine when required. Auto transmissions get change to, but not flushed. I hear it's the flushing that causes issues.

I agree, change fluid and filter if there is one. Do not flush.

BTW. this advice is the same that Allison has-- no flush!

Change them today.

My transfer case takes ATF. Get the right fluid for your vehicle.

Good idea to change them in the differentials and transfer case. Make sure you use the proper gear oil and make sure it’s a quality synthetic such as Amsoil or Mobil 1.

time2roll wrote:
Get the right fluid for your vehicle.

Especially for the transfer case, get the exact OEM fluid from the dealer.