75W-110 Gear Oils

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Ford specs 75w-90/80w-90 for civilian Vics and 75w-140 for CVPIs but it's the same diff...

I'm torn between using 75w-90 for improved fuel economy and 75w-140 for better protection during aggressive driving or extended highway trips that may or may not involve higher than suggested operating speeds. Obviously my usage is not as severe as typical police use, but it's also not your average grandma driving.

It looks like there are a few companies making 75W-110, one of them being Amsoil. I've never used Amsoil products before. but I'm thinking this seems like a good middle ground in terms of fuel economy and protection at high temperatures.

Anybody used 75W-110 before, and if it's a good idea, where can I buy this at the best price? The price seems reasonable compared to other quality synthetic gear oils like Royal Purple (which is what was gonna end up in this diff before I came across that Amsoil), etc. I plan to change it every 60K miles.

https://www.amsoil.com/shop/by-product/gear-lube/severe-gear-75w-110/
 
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I was thinking the exact same thing this morning. I just did the differentials on both of my Jeeps and plan on doing my 88 E-150 possibly next week. I was thinking of using 75W-90, or 75W-110, which is not easy to find locally. I shot my buddy Trav an email and went with his recommendation of 75W-140 for the Ford.
 
I'd just use 75w-140 if you're worried about it. Amsoil has a pretty good price on it. Get with Pablo.
 
Originally Posted By: hatt
I'd just use 75w-140 if you're worried about it. Amsoil has a pretty good price on it. Get with Pablo.


I wouldn't say worried is the right word. But for the same price as 140, the 110 will give be better fuel economy and I drive quite a bit. I'm sure calming down my driving habits matters more than the viscosity of the gear oil in the rear diff but money saved is always good.
 
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If you're worried about fuel economy use the recommended 75w-90. Pablo is an Amsoil rep here.
 
75W-110 is the upper viscosity that 75W-90 used to be before the J306 tables were updated. I have used Amsoil 75W-110 in the front axles of my 2010 FX4 and my 2015 F250 with no issues.
 
Originally Posted By: 2015_PSD
75W-110 is the upper viscosity that 75W-90 used to be before the J306 tables were updated. I have used Amsoil 75W-110 in the front axles of my 2010 FX4 and my 2015 F250 with no issues.


Very intersting information, thank you. Looks like I will be purchasing 75W-110 when I change the diff oil!

Originally Posted By: skyactiv
I'd use this myself:

http://www.klotzlube.com/automotive.html


Any reason in particular? Is this better than the Amsoil product?
 
I was in a similar situation.
My 1998 GMC C1500 called for 80w90 in the rear diff. I was planning on doing quite a bit of towing with it, had a couple trips towing my camper.
I ended up using the 75w110 Amsoil Severe Gear and my truck towed the camper from NY to Illinois, to the Adirondack mountains in NY, and another trip across NY.
The 75w110 was just the thing, and you would be hard pressed to find a gear lube better than Severe Gear!
 
Used the Amsoil 75W110 the year it was introduced and never looked back and it has served my x-case and differential quite well.
Presently on RL 75W110 on both units, personally prefer Amsoil, when it came out after 100K on it, it was slightly dark - could have gone further (don't tow on my vehicle)
 
You won’t see a fuel economy difference between any of those weights. Go with 75-140. I have a Mercury Marauder, and Ford back spec’d my car to 75-140 from 80-90 for a reason, in a TSB. The reason was axle shaft heat treating, but when I put axles in it I went ahead and filled it back up with Valvoline Synpower 75-140. The extra protection is worth the extra $1 a quart. I changed and the car still gets 20mpg if I drive like a sane person. Also running 5w-30 in the engine... if you ask your government I should be getting atrocious fuel mileage.
 
I just ran 260k miles on the Dana 80 in my Dodge, about 130k of that towing, and the axle now needs a rebuild. 75W-90 the whole time. Would it have lasted longer on 110 or 140? Or should I be happy with 260k miles?
 
Originally Posted By: 69Torino
You won’t see a fuel economy difference between any of those weights. Go with 75-140.
+1

Originally Posted By: A_Harman
I just ran 260k miles on the Dana 80 in my Dodge, about 130k of that towing, and the axle now needs a rebuild. 75W-90 the whole time. Would it have lasted longer on 110 or 140? Or should I be happy with 260k miles?

Yes, higher KV@40*C in 110 (140 cSt up) and 140 (175 cSt up) offering far thicker MOFT than a KV@40*C 100 cSt 75W90 would've provided stronger components protection far beyond the 260k miles stated.

So much for FE in low viscosity gear oils in modern gear-train components with modern power-train modules and modern oils.
 
Im not an Amsoil fan boy, but Amsoil Severe Gear worked better than anything else in our race cars. Like ALOT better. I usually use Mobil 1 in street vehicles because I can go to the store and buy it, but for something severe or a classic that I will keep forever, I will use Amsoil.
 
Originally Posted By: 69Torino
You won’t see a fuel economy difference between any of those weights. Go with 75-140.


+1

I have one panther with Delo ESI 85W-140, and 2 more with Redline 75W-140NS. I see no difference between those 2 and the 80W-90 that was there before.
I put the Delo in by mistake and was worried at first, but then recalled we did this on cabs years ago and a few users on this forum with more experience assured me there'd be no difference. Just confirming that. Lost one axle on 80W-90 after a 8k mile road trip and this is how it came to be after a swap of the whole rear end. Another option is to look into Yukon axles proactively for that particular rear end
 
Originally Posted By: A_Harman
I just ran 260k miles on the Dana 80 in my Dodge, about 130k of that towing, and the axle now needs a rebuild. 75W-90 the whole time. Would it have lasted longer on 110 or 140? Or should I be happy with 260k miles?
Are Dodge axles the ones that require short OCIs?
 
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