ST 75w90, what do you use it in?

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What are you using Supertech full synthetic 75w90 gear oil in? How long have you been using it?

I bought 2 quarts a few days ago to change out the front differential in my sisters 05 Trailblazer, I haven't changed it yet.

I'm considering using it in my 2017 Silverado 3500 HD in the front and rear diffs.

Who makes Supertech gear oil? Does anyone know where I can find a PDS for it? I want to know what the KV100/KV40 viscosity looks like.

I bought some Starfire 75w90 a while back, the bottles look identical to the ST bottles, just a different color.

The Starfire 75w90 properties look better on paper to me than Mobil Delvac 75w90.

ST 75w90 Pics

75w90 options: (prices include tax)

Starfire 75w90 for. $9.81/qt
Mobil Delvac 75w90 for $8.28/qt
Supertech 75w90 for $5.84/qt
Valvoline Synpower 75w90: $8.47/qt
 
I'm running a 50/50 mix of SuperTech 75w-90 and 75w-140 in my 2018 Silverado 3500 HD and will post an oil analysis in about 20,000 miles.
 
Been using it for last few years in my GM full size rigs, Suburbans and Silverados and ALL had the G80 posi


Haven't had any issues so far ???


Ya can't beat FULL SYN for under $6 a qt !!!


Dave
 
Originally Posted by wwillson
I'm running a 50/50 mix of SuperTech 75w-90 and 75w-140 in my 2018 Silverado 3500 HD and will post an oil analysis in about 20,000 miles.

I'm looking forward to your UOA.
I checked the rear diff fluid level in my 2017 3500 HD last night, it was 1.1 to 1.2 inches below the fill hole (spec is 0.6 to 0.8 below fill hole). It's slightly underfilled. I have 12.6k miles, I think I might wait until about 15k miles and change the front and rear diffs as well as the transfer case fluid.

I took my dremel and marked a 90° "dipstick" at 17 & 21mm to make checking my rear diff fluid easier in the future.

0C4E8DFD-FC59-4116-93AE-5376CE1F8B46.jpeg
 
Just changed out my 4Runner with it. Not the 75w-90 but the 75w-140. About 500 miles on it and no problems. Warren Distribution makes it where I live. Go to their site and look up the PDS for Mag1. I believe it's the same stuff. I'm happy!
 
I use it in the transmission of my RZR and also rear diff of my Suburban. Best bang for the buck i have found.


Meets SAE J2360

"all lubricants which have gone through the SAE J2360 approval process have been shown to provide acceptable performance in controlled field tests in both light-duty and heavy-duty equipment. The light-duty portion of this test requires that the lubricant protect the equipment from life-limiting distress for 100,000 miles of service with no oil change"

https://www.lubrizoladditives360.com/sae-j2360-standard/
 
Currently not running it in anything. I will say, I've never had a problem with SuperTech lubricants and would use them without hesitation. That said, I don't like the labeling on newer ST Synthetic 75w90 bottle. As compared to the older bottle (and other current ST oil/lube products) which were very specific about specs met, the new bottle info seems vague imo. I won't say sketchy, but certainly vague in comparison. Not saying I wouldn't use it, but it doesn't seem in line with the specs labeling of other ST oil/lubes.

It may be the same as the noted MAG1 made by Warren Dist/WPP. Imo, they should label the ST product similarly and/or have a similar PDS (eg., meets API GL-5) as reference. My .02
 
If it ever stops raining long enough, I plan on running it in my Subaru's transmission and differential.

I use ST gear oil exclusively.
- ST 75w140 in the rear of my pickup
- ST 80w90 in the front of my Jeep
- ST 85w140 in the rear of my Jeep

I thought the 75w140 used to be rated for limited slips but turns out it isn't. Found that out after putting it in. Whatever was in there before was causing the
limited slip in my pickup to chatter, but that seems to have stopped with the ST gear oil.
 
Put it in the Subaru third member. Seems to be doing fine - in fact it stopped a whine back there on the highway after a hour running at 75 mph.

Or maybe my hearing is just shot after the Easter Service organist in Hanover was playing too loud - some ELP type thing.
 
Originally Posted by Miller88
I thought the 75w140 used to be rated for limited slips but turns out it isn't

The synthetic gear oil is. I emailed WD and they confirmed it.
 
Originally Posted by Sayjac
Currently not running it in anything. I will say, I've never had a problem with SuperTech lubricants and would use them without hesitation. That said, I don't like the labeling on newer ST Synthetic 75w90 bottle. As compared to the older bottle (and other current ST oil/lube products) which were very specific about specs met, the new bottle info seems vague imo. I won't say sketchy, but certainly vague in comparison. Not saying I wouldn't use it, but it doesn't seem in line with the specs labeling of other ST oil/lubes.

It may be the same as the noted MAG1 made by Warren Dist/WPP. Imo, they should label the ST product similarly and/or have a similar PDS (eg., meets API GL-5) as reference. My .02

Says on the back of the bottle API GL-5. Motor oil shows full specs and certs.

You have to remember the knuckle draggers these products are marketed for. They don't read the bottle. They read the price.
 
Knuckle Draggers?

Gear oil has been a ripoff for to long.

Easy to make , high volatility base stocks.

6 bucks a quart sounds about right.
 
Originally Posted by BlakeB

Who makes Supertech gear oil? Does anyone know where I can find a PDS for it? I want to know what the KV100/KV40 viscosity looks like...




Whether it be the Blend or the synthetic, Warren of Omaha Neb makes it and it is essentially a Mag1 product:
 
Last edited:
Quote
…Says on the back of the bottle API GL-5.....
What it actually says is "For use where API GL-5 is specification ." Some might say it's a distinction without difference. However, I compared it to Valvoline Synthetic Gear Oil right next it at WM and on the bottle it says, "Meets or exceeds API GL-5 specification." To me there's a difference.

As I noted, it could be MAG1 which is made by Warren Dist/WPP. However unlike ST, it has an available PDS which clearly shows all specifications met. That said, WM frequently uses different blenders depending on area, I've seen no authoritative evidence it is definitively the Mag1 product.

Link to MAG1 75w90 PDS
 
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