Any downside to 75w-140 v 80w-90 in a differential?

[cb4017]

I'm mostly curious to what others think.
My last couple of vehicles I changed out rear diff fluids with Amsoil 75w-140 Severe Gear because they saw use in extreme conditions off road and towing a small travel trailer. They were both Jeep Wranglers with D44 rear axles with LSD. Worked great and never had an issue.

I just bought a new Ford Ranger 4x4 which also has the D44 axle but with an electric locker. It will also see off-road use and trailer towing. Ford specifies 80w-90. My plan is to change out the fluid at around 5,000 miles with the Amsoil 75w-140.

I'm sure it would be fine other than a possible small hit on economy.

Oh, should add that I am in Northern Nevada where it can get hot in the summer and possible to see temps in the low teens in winter.

Thoughts?

 

[Kuato]

Sounds like a good plan to me, considering your temps & usage. Hit in mpg will be minor if any.

 

[JTK]

I never bothered with 80w90 and always substituted 75w90.

To me, the only possible downside you might see with 75w140 would be fuel economy loss by a tiny fraction of a MPG.

 

[CarbonSteel]

I have the Dana 44 electronic lockers in my Wrangler and FCA recommends 75W-140 with the towing package (which is a foobar on their part since they filled it from the factory with 85W-90 even though I have the towing package). I have ran 75W-140 in all of my rear axles since 2010 with no issues whatsoever. Your right foot or a headwind will have more of an impact on MPG than any viscosity change ever will.

I would run it without a second thought--better to have more protection and not need it versus the reverse.

 

[wpod]

Not at all 75w- 140 is my go to lube. It is in my 2006 Tacoma, 2015 Ford F150 and the 2018 Ford F350.

 

[spasm3]

It's in my avalanche

 

[Kawiguy454]

I put M1 version of that in everything i own with ring/pinion for 20 years and nary a problem. Even put in my lawn tractor diff, shaft drive C14 cycle hub and Yamaha SxS diffs no problemo.

 

[DGXR]

I've been wondering the exact same thing. Glad to find this thread.

 

[meep]

should be fine, though if it were me I’d stay in spec but go to something like amsoil severe gear with the stronger additive package. I doubt it would matter, but seems that the thicker oils are not as good at cooling in diffs. I can’t recall if it’s because it adds resistance or if it’s something about not carrying the temps off the gears as well - it’s been a while since I stayed up on that, but as I said, doubtful it would make a difference.

btw tell us about the ranger! This is the 4cyl turbo, right? I’ve had an eye on these and would have preferred that to my f150 were it not for the size of our camper. Do you like it??

m

 

[slacktide_bitog]

75w140 seems to cost a lot more than 75w90 for some reason, so no point in spending the extra money. Does Amsoil charge more for the 75w140 than the 75w90?

Walmart charges $6.97 for 75w90 and $11.86 for 75w140

It probably won't hurt anything, though.

I like that easy pack pouch the Amsoil comes in! It makes it easier to fill the diff! You don't have to worry about being able to tilt the bottle at the angle needed to pour it in
Valvoline used to offer their gear oil in a pouch

 

[cb4017]

should be fine, though if it were me I’d stay in spec but go to something like amsoil severe gear with the stronger additive package. I doubt it would matter, but seems that the thicker oils are not as good at cooling in diffs. I can’t recall if it’s because it adds resistance or if it’s something about not carrying the temps off the gears as well - it’s been a while since I stayed up on that, but as I said, doubtful it would make a difference.

btw tell us about the ranger! This is the 4cyl turbo, right? I’ve had an eye on these and would have preferred that to my f150 were it not for the size of our camper. Do you like it??

m

Yes, this is the truck with the 2.3L Ecoboost engine. I bought the XLT 4x4 with the FX4 Off Road package. I've only had it for a few weeks and I like it. PLENTY of power. In sport mode it's a blast. Good fuel economy. Plenty of room for what I do. 7,500 tow capacity so no problem with my small
Thanks for your thoughts everyone. My truck will be getting the 75w-140 when I change the diff fluid.

 

[SoNic67]

Instead of recommended 80W90 I am using Redline 75W110. Full Synthetic, $24 for 1Qt that I need, and I don't change it that often, it is worth the price to me. I choose that because is not so drastic of a change as going to 140.

 

[dblshock]

with more VI maybe wear out quicker?

 

[Snagglefoot]

Isn’t 80w90 traditionally a conventional oil? Moving to a synthetic is a good idea.

 

[buck91]

I had an interesting experience with 80w90 vs 75w140.

when we had an explorer sport with the 3.5eb and was I changed the PTU oil a couple times. The first time I did flushed it first. Then cleared the flush out with some 80w90 I had before final fill with 75w140. This wasdone on a hot 95F afternoon and I had to fill the ptu through a 3/8 vent hose. Needless to say a very slow process. While both oils tooka long time to fill the Dino 80w90 was FAR slower than the synthetic.

 

[SoNic67]

Kinematic Viscosity @ 40°C, cSt (ASTM D445) for 80W-90 is around 120, while for 75W-140 is around 177. For 75W-110 is around 140.
The measuring temperature for the last number is 100°C, while for the first number is at -26°C (for 80W) and -40°C (for 75W).

 

[4WD]

I have the Dana 44 electronic lockers in my Wrangler and FCA recommends 75W-140 with the towing package (which is a foobar on their part since they filled it from the factory with 85W-90 even though I have the towing package). I have ran 75W-140 in all of my rear axles since 2010 with no issues whatsoever. Your right foot or a headwind will have more of an impact on MPG than any viscosity change ever will.

I would run it without a second thought--better to have more protection and not need it versus the reverse.

2 of us (myself with a 2020 and another guy with a 2019 & 2020 Rubicon) have been searching Owners Manuals for the 75w140 = can’t find it … What section?

 

[CarbonSteel]

2 of us (myself with a 2020 and another guy with a 2019 & 2020 Rubicon) have been searching Owners Manuals for the 75w140 = can’t find it … What section?

 

[4WD]

Hmm … my rear axle is M220 …

 

[bruce381]

you plan is fine do not over think it