I was thinking about picking up 6qts of the HPL 75w85 for my truck with the weekend deal going on. I've used Amsoil for some years in all three of my vehicles. The two are pretty close to the same price. Knowing that they are both top notch, assuming cost was even is there one that is "better" than the other?
Amsoil Severe Gear or HPL?
- Thread starter Johnny248
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I also realized that last time I changed it on the Toyota, I used 75w90 instead of 75w85. I'm sure it's not going to make much it any difference. Do I stay with the 90 or go 85?
Thanks Glenda. I'm not exactly sure what these numbers all mean. I think it means the HPL is "thicker/heavier" and has better VI. The Amsoil seems to have better wear protection?
Also use Amsoil SVG but would run HPL without any issues. Been using Amsoil SVG as well as auto and manual transmission fluids for years without issue so never saw a reason to change.
Only Amsoil product that mildly annoyed me was the SS 5w-30 back around 08-12. Smelled like gun oil in the cab of my old Mazdaspeed6. Mobil 1 never had that odor issue and the new SS 5w-30 doesn't have that issue in my wife's 2.0 ecoboost, just an older formulation in that one vehicle.
@Johnny248 either of these gear oils will work great for you & will likely be more than you actually require.
It was about $4 less of the HPL. I accidently ordered the HPL while I was trying to get to see what the total is lol It's all good, I was probably going to go that way but now I'm not going to get an Amsoil tire pressure gage 
Severe Gear 75W90 in my 85 spec rear end. Saw a mpg to 2 mpg difference. Nothing to sweat about.
CleanSump
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I've only used SG in every vehicle I've had for over 30 years and never a failure. I do have some Redline in the garage that I've never gotten around to using.
Amsoil in one, Redline NS in the other because Amsoil and HPL don't make a gear oil without the limited slip add pack which my LSD manufacturer doesn't want in the oil.
What's the source on this?
Pour point on the HPL is markedly lower than AMSOIL. Must be a lot of PAO in the HPL. Not sure how to interpret the rest.
My “mega 75w90” thread
Ah, this is a compilation of published stats from the manufacturers?
Nope, thorough lab testing of what actually ended up in each bottle. Each of those tests was performed on bottles I bought and several that were donated. No marketing pomp & circumstance, just real data of what people would actually get if they bought a quart of those oils.
Stay away from the one that shears 30% in the KRL test, IMHO, even if it’s given to you in bulk quantities.
How applicable is the 4 ball wear results? Because amsoil is the lowest
Lower is better. Less wear. Scar size in mm.
Amsoil SVG is a really, really good gear oil. No complaints if that’s what you use; even HPL acknowledges great products in the marketplace (like Mobil 1 Full Synthetic 0w40 as well). 4-ball wear and weld tests are applicable to gear sets as they are under extreme pressure and potential metal-to-metal contact.
All gear oils (and engine oils FTM) are always a compromise on something. The chart in my thread is mere data; IMO one of the most important things for a gear oil is shear stability, cold flow properties, then wear/weld protection. If anything, my testing thread shows there’s plenty of great choices available, but also some products to avoid.
AMSoil had the smallest % viscosity loss but HPL was still thicker after KRL. The HPL would have the best wear protection but it's really splitting hairs between the top 3 or 4.
Exactly. The “top tier” gear oils are all really, really good. If changed at sensible intervals for the application it’s unlikely anyone would ever see a material difference in performance or wear.
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