Here's the Blackstone analysis of the Rear diff Toyota Factory fill after 5000 miles. (attached)
Basically they are saying the high amount of metal in the oil is no surprise from a break-in sample.
Iron came out at 177, Boron at 207 and Phosphorus at 1411 (!). The rest of metals are 0 or under 5.
cSt viscosity @ 100 C (212 F, which is working temperature) came out as 11.07, which seems to be typical for a 75w-85 gear oil.
I expected a lot more spread on the metal traces. Instead there are 2 small spikes for Iron and Boron, and a huge spike for Phosphorus.
Here's a comparison of the cSt-s @ 100 C for various gear oils:
AMSOIL Severe Gear 75W-90 cSt @ 100 C = 15.9 (this is what I used)
Mobil 1 75W-90 cSt @ 100 C = 14.6
Red Line 75W-90 cSt @ 100 C = 16.1
Red Line 75W-85 (a.k.a., LightWeight Gear oil) cSt @ 100 C = 11.5
MOTUL Gear 300 75W-90 cSt @ 100 C = 14.2
SynPower Valvolilne High Performance 75W-90 cSt @ 100 C = 15.6
Looks like Red Line 75W-85 would be a perfect match as far as working temp viscosity.
Yikes, I've never heard this one. Perhaps it's a good idea when rebuilding a dif so the brake cleaner can completely flash off, but in a sealed dif? My (probably unfounded) concern would be that any residual brake cleaner would do something to degrade the fresh oil. Won't be using this practice myself - simply swapping gear oil has been fine for my vehicles in the past, and isn't a guideline I've ever read during the process of rebuilding my M3's dif.
Yikes, I've never heard this one. Perhaps it's a good idea when rebuilding a dif so the brake cleaner can completely flash off, but in a sealed dif? My (probably unfounded) concern would be that any residual brake cleaner would do something to degrade the fresh oil. Won't be using this practice myself - simply swapping gear oil has been fine for my vehicles in the past, and isn't a guideline I've ever read during the process of rebuilding my M3's dif.
Yup. I have been using Amsoil 75w-90 synth for 55k miles, no issues. Currently at 110k and perfectly strong.anyone using anything other the the "75w" for the transfer case from toyota?
Diff is not sealed, it's vented. Brake cleaner also evaporates quickly. Spray in, let it drain out, give it 5 minutes, done. I've cleaned every single diff I've ever serviced without a single issue.
Brake cleaner doesn't last long. Do wear eye protection.
Toyota Differentials (OEM) run LT 75W-85 GL-5 Gear Oil
Nitro Gears recommends using 80W-140 Gear Oil.
I changed the OEM factory diff fluid on my 2005 at 100,000 miles, and don't recall any issues - including pieces in the oil. It was black. Viscosity seemed thin. Hard to judge.
I used Valvoline 80/90 weight - which is recommended (with normal use)
4runner has always driven noiseless and fine.
I'm at 150,000 miles and may do a 6 quart DF soon. Rear-end holds total 12 quarts.
D/F is all Ill do. Hope 6 quarts Drain out - or I'll have to do it twice or call a dealer for advice.
I never changed this on any car I ever owned. Had a new GMC Jimmy - sold at 88,000 miles at ten years old.
two-year-old Cadillac - never touched it - 100,000 miles.
What is the manufacturers recommended maintenance schedule?
I think the posts here are way over maintenance on any rear ends (that don't tow).
The normal service interval for the differential is 90,000 miles so if you cut that in half you should have no issues. The severe service interval is 60,000. differential service - Bing
A heavier weight oil is better for the longevity of the gears, and they don't really care about your MPGs.Sorry to resurrect an old thread, but my searching has not found any clear answers.
So, I am curious...
:noidea:
Why the difference?
What is the risk of running the lighter oil with the Nitro Gears?
.
A heavier weight oil is better for the longevity of the gears, and they don't really care about your MPGs.
I've been running 140w for close to 200k miles on my Nitro gears, but I wouldn't think twice about switching back to a 90w.
Yeah, since the initial post I have talked to a few guys about this, and 2 out of 5 people are running the 90W with no problems. However, like most people with 4Runners, they don't really care about their fuel economy. So, they don't track it. Although they have noticed the dash numbers are usually higher since regearing. Most of them have 285+ tires. I am running 255/75 C-Loads because I drive my vehicle so much, and I h ate throwing away money in fuel.
Thanks for the reply!
When you cruise on highway now how do your rpm at 60 mph compare to previous with 3.73 gears? 3.73 to 4.56 is a significant change.