Differential Fluid

Once a year?
It's recommended every 30k miles if I'm not mistaken. The average person drives 14k to 15k miles a year so going by the average person and Toyotas recommendations you only need to change it every 2 to 3 years and depending on the person it could even be every 4 to 5 years. If you do water crossings or considered severe use 30k is great or could be changed sooner but if you do all highway then you could go over 30k and be just fine.

People don't change their diff fluid for 100s of thousands of miles and some how their diffs aren't exploding left and right. The main thing is actually changing it and using what is compatible with your diff.

 

Just want to offer a correction here. For the differentials, GL5 is the recommended fluid no matter your transmission choice. GL3(Obsolete) and GL4 are for the actual transmission itself. The manual transmissions in our trucks use

$28 75w-90 Synthetic Gear Lube - 1 Quart (Pack of 2)

75w-90 Gear oil (GL4). The automatics use WS automatic transmission fluid.

Reason for the GL4 spec for manuals is because some of the extreme pressure additives used in GL5 gear oil is corrosive to some synchronizer materials.

 

Ok I was basing it off most ppl putting around 30k per year on their trucks so the $20 more for you ppl saying just buy the cheap stuff or the stuff on the Walmart and local store shelves is even cheaper per year if you’re only changing your differential fluids every 3 or 4 years.. I go by severe driving conditions bc I use my truck for everything except for long trips when more comfort and room is wanted

 

Correct.. was half asleep when posting last night. Good catch.i definitely should’ve specified transmission snd differential fluid.
GL5 for diffs regardless.. GL3 (very expensive and hard to find) or GL4 for manual transmission fluid.
GL5 WS for automatic transmission fluid

 

FWIW East Coast Gear Supply (ECGS) recommends Lucas non-synthetic 85-140 for the differentials.

 

Now that our winter/snow driving is over in my area, I just crawled under the truck and did the manual trans, transfer case, and front/rear diffs all using 75W-90. Found a steal (shipping dates are the only issue with this seller) on Amazon on this deal:

$70 Ultra1Plus SAE 75W-90 Synthetic Gear Oil API GL-5 | 2 Gallon (8 QTS)

2 GALLONS FOR $69.99 and only had to buy 1 extra quart because I needed about 8.5 quarts total. Got a set of flat and crush washers on Amazon to replace all existing for $5.