Differential synthetic gear oil question

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I am getting ready to change out the differential gear oil in my Dodge Ram 1500 4x4 with 3:92 gears and it is an anti spin (POSI) rear end. It calls for synthetic gear oil. I am thinking about using Valvoline synthetic gear oil. Is this a good gear oil for the money? I do not abuse the truck in any fashion. I don't mud it or even tow allot with it. I has 60,800 miles on it right now. Just bought it and trying to service it as I want it to last a long time. Any recommendations would be appreciated. Thank You
 
Valvoline gear oil is great stuff. Follow gear oil specs (75-140, etc) and your good to go. Most all synthetic gear lubes have friction modifier already in them so you shouldn't need to add Mopar friction modifier to your gear lube. Hope this helps.
 
I also used the Valvoline Synpower when I did gear oil in my old F250SD... Of course, I didn't keep that truck long enough to worry about the longevity of it.

I would use Synpower again if I felt like it. Although to be honest if its a vehicle where I really want a synthetic I'd go with Amsoil, otherwise I'm not sure if I wouldn't just go dyno oil. Couple of the most reputable rear end shops I've dealt with have always recommended dino oil. In fact, they refilled my Mustang with xw140 dino when I got the 3.73's installed last summer. ....but then I have Amsoil in my F150, so....
 
The only good study on diff oil I've seen had a bunch of tests run to see how well they did: http://www.syntheticwarehouse.com/brochures/g2457_gearlube_study.pdf

Amsoil, Mobil1, GM's house brand, Castrol Syntec, and Redline ranked near the top. I'd only buy those, based on real tests done. Other opinions are just hearsay. Stick with the evidence we have.
That's if you want the most life out of your truck, which most of us care about.
Otherwise, if you don't care, any GL-5 gear lube will do.
 
Originally Posted By: oil_film_movies
The only good study on diff oil I've seen had a bunch of tests run to see how well they did: http://www.syntheticwarehouse.com/brochures/g2457_gearlube_study.pdf


Wow, Royal Purple MaxGear did horrible. Guess that's getting drained and replaced with something else next time. No UOA but the first run of RP drained out the same purple color as when it went in and looked new. I wonder how Motul would have ranked amongst them.
 
Originally Posted By: oil_film_movies
The only good study on diff oil I've seen had a bunch of tests run to see how well they did: http://www.syntheticwarehouse.com/brochures/g2457_gearlube_study.pdf

Amsoil, Mobil1, GM's house brand, Castrol Syntec, and Redline ranked near the top. I'd only buy those, based on real tests done. Other opinions are just hearsay. Stick with the evidence we have.
That's if you want the most life out of your truck, which most of us care about.
Otherwise, if you don't care, any GL-5 gear lube will do.



Wow, fantastic article! Definitely affirms my choice for ASG in the truck. Looks like the Castrol dino did pretty dang good, though.
 
Is that Amsoil report 10 years old ?
At the price point some in the test are at these days - don't overlook Delvac 1 gear lubricant ... check it out on website and it is the stuff HD drivers like Tired Trucker use. (I use in Eaton locker)
 
Originally Posted By: Bambam
Hmmmm an Amsoil backed test, and Amsoil is near the top???


Amsoil is reputable, has been for 40 years. Quality products.

It's like 8 years ago when Valvoline NAMED, by name, Mobil 1 5w30 as failing SN's Seq. IVA wear tests. NO LAWSUIT from Mobil, because Valvoline backed up their claims with valid tests.
Same here! Amsoil would get sued for making false claims (also, no FTC lawyers got involved). Amsoil was never sued over the VALID tests.

I'd use those certified tests instead of somebody on the internet claiming "I use XX Brand, and it's oily."
 
I installed a new posi/trac loc carrier in my explorer and I have almost 4000 miles on it with Vlv syn 75w140. Works perfect with no chatter noise and lays down two marks when called for. No modifier added. I guess your Dodge would be similar, if it calls for friction modifier. Can't say that is a scientific test but I'm satisfied.

I got a good deal on it from pep-boys over the holidays, even so it is very fairly priced.

I guess the next step would be Mobil 1, RP(if you believe their marketing dept) or Amsoil, but the jury is out how much more that is worth to you.

If I towed heavy loads I would probably pick Amsoil, but it is a bit expensive for my tastes. I don't think I will have the truck forever either, maybe if it was 10 years newer.
 
see this list:
http://p-r-i.org/other-programs/automotive-qpl/lubricant/
open the link for the "current QPL listing".

All these lubes are not only tested for content, but to a strict performance standard. This is a former Mil-Spec standard for heavy duty GL-5 fluids.
Anything that passes this standard will more than ever protect your diff.

Do some research on the SAE j2360 standard itself; very robust. The API GL-5 cert is OK, but it only reports what would be confirmed in a VOA. The J2360 spec actually looks at the lube in terms of vis retention, anti-foaming, etc. It's more like a UOA report of sorts. You won't see wear metals, etc in the list, but you'll see that any of these lubes will do a fantastic job because of the tough testing in the standard.

You will note that there are plenty of lubes here. Several brand names, etc. Please also note that there are dino oils that also pass this spec! You don't need a syn to have fantastic protection.
 
Last edited:
Originally Posted By: ford46guy
I installed a new posi/trac loc carrier in my explorer and I have almost 4000 miles on it with Vlv syn 75w140. Works perfect with no chatter noise and lays down two marks when called for. No modifier added. I guess your Dodge would be similar, if it calls for friction modifier. Can't say that is a scientific test but I'm satisfied.

I got a good deal on it from pep-boys over the holidays, even so it is very fairly priced.

I guess the next step would be Mobil 1, RP(if you believe their marketing dept) or Amsoil, but the jury is out how much more that is worth to you.

If I towed heavy loads I would probably pick Amsoil, but it is a bit expensive for my tastes. I don't think I will have the truck forever either, maybe if it was 10 years newer.




Totally off topic but I gotta ask; what posi did you put in? After installing the Eaton Posi in my truck I had one [censored] of a time getting it to quiet down and smooth out.
 
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