75w85 VS 75w90

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Aug 20, 2003
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ottawa
Hey Everyone,

Our 2019 Santa Fe specs 75w-85 in the transfer case and rear diff.
In the past I have used 75w-90.

I was wondering if you all think the 90 weight would be better for longevity VS .005 mileage increase for the 85.

Thanks
 
Super Tech 75W90 Full Synthetic $5.86/qt API GL-5 and MT-1, SAE J2360

Ive never seen proof of 'longevity'.. but those specs and price are impossible to beat.
 
I would assume the 85 is more shear stable performance for the X-fer case. I would imagine its same as 90 but with less VM. Depends on the below freezing performance - maybe the 75W85 flow MUCH better.. My Nissan hated the dealer installed HD 80W90 MOBIL
Just Valvoline or Pennzoil or Castrol or Supertech 75w90 in the rear would be fine.

I put supertech 75W90 in the wife's Crosstrek with a noisy rear and .... its not noisy now! I though the dealer didn't change it when last requested, but the fluid looked
new and no metal fuzz on the drain plug magnet.
Maybe just a fluke.
 
Last edited:
Originally Posted by nicholas
Hey Everyone,

Our 2019 Santa Fe specs 75w-85 in the transfer case and rear diff.
In the past I have used 75w-90.

I was wondering if you all think the 90 weight would be better for longevity VS .005 mileage increase for the 85.

Thanks

I have same dilemma. I wanna use Redline, but Redline offers 75W85 for TC and differentials, while Toyota wants 75W90.
 
Most 75w85 seems to be conventional while most 75w90 is synthetic now.

I would run the 75w90 myself.
 
Originally Posted by Jimzz
Most 75w85 seems to be conventional while most 75w90 is synthetic now.

I would run the 75w90 myself.

Redline 75W85 is full synthetic.
 
Originally Posted by nicholas
I am looking at Redline for both 85 and 90 weights.

What do you y'all think?

I would pick RL 90 then.
 
Originally Posted by Jimzz
Most 75w85 seems to be conventional while most 75w90 is synthetic now.

I would run the 75w90 myself.


Are you sure 75W-85 can be had in a conventional? My understanding of the recommendation of 75W-85 was to actually force people into a synthetic gear lube because there is still some conventional spec's 75W-90 out there.

That being said, I have used a synthetic 75W-90 in place of the 75W-85 gear oil call outs in all my Toyota's with no issue.
 
Originally Posted by ad244
Where's the 110 Crowd?


Nice SUV vehicle.

Why use a SAE 110 if it doesn't need it?

With the 2.XL engines you develop an average of 180+ Lb.ft of torque.

I am not downplaying this vehicle by any means but this is not exactly a Cummins axle-torque-twisting engine.

I would say the Redline https://www.redlineoil.com/Content/files/tech/75W85_GO_PROD_INFO.pdf gear oil would work just fine.
 
I use Amsoil Severe Gear 75w-110 in my Tahoe. I switched to it from 75w-90, before I joined here, because I figured it would help with the towing I do. I tow a 6,000 lbs load about 200 miles round trip twice a month. I'm not sure if it helps or not.
 
I have a 2019 Santa Fe(AWD) also and decided to go with what Hyundai recommends... 75w85 and picked up two bottles of Red Line 75w85..


Hey Everyone,

Our 2019 Santa Fe specs 75w-85 in the transfer case and rear diff.
In the past I have used 75w-90.

I was wondering if you all think the 90 weight would be better for longevity VS .005 mileage increase for the 85.

Thanks
 
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