Gear Lube White Paper

[dynomax]

As I want for next month's lift install when I have a week off that I don't need my truck to get to work... thought i'd change the diffs & xfer case

 

I Was just about to walk out with 5L of royal purple ($22/L) 75/90 today, and the second option was Lucas($15/L)... Glad I bought neither!

 

This white paper on gear lube was a surprisingly interesting read.

 

http://www.google.ca/url?sa=t&rct=j&q=lucas%2075w90%20gear%20oil%20reviews&source=web&cd=1&ved=0CCIQFjAA&url=http%3A%2F%2Fwww.synthetic-oil-tech.com%2FGear%2520Lube%2520White%2520Paper.pdf&ei=gERhT8miF6nz0gHQ8N2kBw&usg=AFQjCNEBEzgKLQvyLS1II1GfRl8rhAaQ_Q&cad=rja

 

Anyway, I will have to search out some M1 or Amsoil (have yet to find any Amsoil product in this city, so M1 might be my only choice).

Edited March 15, 2012 by dynomax

[Towncivilian]

There are a few used oil analyses of various brands of gear oil on Bob Is The Oil Guy which you may want to look at to help gain some insight on the various lubes.

 

Differentials are pretty much bulletproof - you see vehicles with 200k or 300k with the factory fill still rolling around. I ran the factory fill in my rear diff for 123k miles and I've got no problems. I'd say that the frequency of the oil change interval matters more than the gear lube you pick, especially if there is potential water entry. 30k miles on nearly any name-brand gear oil should be quite acceptable.

 

You can't go wrong with Amsoil, I think. My local NAPA sells Amsoil 75W-90 Severe Gear, but for my next diff change I'd probably order Severe Gear 75W-110 from an Amsoil dealer instead. The SAW 90W range was revised a couple years ago; the thinner half of the viscosity range now comprises xxW-90 and the thicker half is xxW-110.

 

Currently I have Valvoline High Performance 80W-90 in my rear diff and from some of the tests conducted in your linked white paper, it ain't too great. I'd planned on changing it at 150k miles (currently at 131k), but I'll do some additional reading of that white paper when I'm not so tired and reconsider.

 

I've got Mobil 1 75W-90 in my father's 2007 FJ Cruiser (also 2WD) which I got 3qts of for $24 after tax from Advance Auto Parts when ordered online with discount code and picked up in store. It's a great deal for an excellent gear lube, in my opinion. I'd run that in a heartbeat too in any differential, especially for the stellar price.

 

That Lucas snot looks real bad. It really shows that they are all marketing. Their "Oil Stabilizer" product is basically brighstock straight 80wt gear lube with no additives. It's garbage that just thickens up the oil and dilutes the additive pack - you'd think with that being perhaps their flagship product they'd at least get gear lube right! Hah.

Edited March 15, 2012 by Towncivilian

[Tungsten]

Mobil1 is amazing. I heard good things about Amsoil. Valvoline seems to be OK. Lucas is definitely more on the marketing side.

[Towncivilian]

After further reading of the white paper, Amsoil seems to blow the other lubes out of the water (see page 19). I'm definitely putting 75W-90 or 75W-110 Severe Gear into my differential when it's conveniently affordable for me. Valvoline 80W-90 didn't do too great, it seems I didn't do enough research before picking it. But still, I'm sure fresh "mediocre" oil is just fine for a brief 15-20k run, and certainly better than 123k old factory fill that's no doubt full of wear metals! Mobil 1 did quite well for a very affordable and available fluid, especially if you've got Advance Auto Parts nearby for even better pricing. I wouldn't hesitate to run that if Amsoil were unavailable or too cost prohibitive. Although it technically didn't meet either GL-5 or SAE J306 requirements due to shear, it barely failed (13.31 cSt when it should've been at least 13.5 csT, big whoop) so I wouldn't discount it. Lucas was just downright nasty.

 

Thanks for providing the link to the white paper, it was some interesting reading.

Edited March 15, 2012 by Towncivilian

[dynomax]

After further reading of the white paper, Amsoil seems to blow the other lubes out of the water (see page 19). I'm definitely putting 75W-90 or 75W-110 Severe Gear into my differential when it's conveniently affordable for me. Valvoline 80W-90 didn't do too great, it seems I didn't do enough research before picking it. But still, I'm sure fresh "mediocre" oil is just fine for a brief 15-20k run, and certainly better than 123k old factory fill that's no doubt full of wear metals! Mobil 1 did quite well for a very affordable and available fluid, especially if you've got Advance Auto Parts nearby for even better pricing. I wouldn't hesitate to run that if Amsoil were unavailable or too cost prohibitive. Although it technically didn't meet either GL-5 or SAE J306 requirements due to shear, it barely failed (13.31 cSt when it should've been at least 13.5 csT, big whoop) so I wouldn't discount it. Lucas was just downright nasty.

 

Thanks for providing the link to the white paper, it was some interesting reading.

 

Yeah, thats why I like this forum so much. Lots of good info.

 

I found Amsoil 75W90 and 80W90 locally, $12.19/jug (not sure if its a Qt or L bottle... either way both are close). I am going to pick it up today and swap this out this weekend. I am convinced when taking off from a cold start the gear oil is still thick. I know when I switched from dyno to synthetic motor oil my morning starts in cold temperatures are much easier.

 

I had an F150 before this, and before switching to synthetic, the oil light would stay on for about 10 minutes on cold start mornings until warmed up... but would never come on in the summertime.

[WOT]

That was probably the best hour and a half I ever spent reading. Learned alot, thank you for sharing. I didnt use a brand in my diff that was in the test. But I sure am going to try and find some Amsoil/Mobil 1 now!!

[Towncivilian]

AutoZone has M1 75W-90 on sale for $7/qt (usual price $11/qt) through April 30th, so if you don't have an AAP nearby to use discounts with and Amsoil is inconvenient to obtain, get some M1 from AZ!