Are all full synthetic rear differential gear fluids made equal?
- Thread starter DR1
- Start date
Are all chocolate chip cookies made equal?
Do you care to expand on this?
I would have to vote no… Red Line is going to be better than a generic AP brand one.
Does all water taste the same.
They can all meet specs but they arent the same.
For example lucas got pounded in the corrosion test and it was a syn 75w90.
Stick with good brand names and and the right product for the application and you dont have to worry.
any particular reason you are asking?
IE the rear end in the 2001 f150 etc. I'd be throwing supertech in that btw.. cheap and works good.
What do you mean by the best.
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I actually have great luck with Royal Purple, but I’m sure M1 & Valvoline synthetic would be fine too, among other major brands. Just get the viscosity right, some Ford rears have been updated to 75W140 or similar from 75W90.
No the biggest thing is the amunt of friction modifier they have, and some like redline you can buy without FM
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- Sep 7, 2021
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Gimpy1 is right. As long as the fluid are all the same specification, the real difference is the amount of Limited Slip Additives in them. Motul has both with and w/o SL added gear fluids. The real question is what type of rear differential is on your car and what is the manufacture's specification/requirement for the differential. When in doubt, you can't go wrong with OEM fluid.
https://www.motul.com/us/en-US/products/gear-300-75w90
https://www.motul.com/us/en-US/products/gear-300-ls-75w90
https://www.motul.com/us/en-US/products/gear-300-75w90
https://www.motul.com/us/en-US/products/gear-300-ls-75w90
JHZR2
Staff member
Care to expand on the Lucas and corrosion testing part of what you posted? I’m not familiar.
It’s hard to say that one is better or worse than another without more context on the needs…. Cold flow, extended drains, etc.
Clean and fresh seems the best option. Something that lasts a long time in use like Amsoil SVG - great lube - but at what point is it not helpful because there isn’t much of a strenuous use and it just gets old and due for replacement. I use that example not to belittle Amaoil SVG. It’s my preferred lube. But in many of my cars it’s not worth running because time, not mileage or severe use will wear it out.
The question becomes how much worse is say, Supertech syn than say Mobil 1 or Valvoline synpower… or the high end lubes. Especially if not always running highly loaded and long distances in short times…
I think you could use any major brand that meets specs, including Supertech, and never know a difference. UNLESS you are towing heavy loads, i think thats where Amsoil, HPL, Redline etc, might be a good choice.
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What is your use case and vehicle?