In this area where AWD is used often and at -20 F temperatures looking for a stout gear oil for rear diff and wondering what others are using, considering one of the Red Line products.
https://www.redlineoil.com/75w85-gl-5-gear-oil
https://www.redlineoil.com/75w90-gl-5-gear-oil
https://www.redlineoil.com/75w110-gl-5-gear-oil

 

Any top brand GL5 synthetic gear oil in 75w-90 or 75w-85 will work in the differential and the transfer case. The 85 was receommended by Toyota but the 90 is easier to find.
Here are threads discussing changing these fluids:https://www.clublexus.com/forums/rx-...-interval.html

https://www.clublexus.com/forums/rx-...id-change.html

 

my vote would be for redline product.

Just make sure you can open the fill plug, before touching the drain plug.

Salim

 

75W-90 GL5 rated gear oil is all you need. The RX350 does not have an high horsepower/high torque engine so you do not have to go overkill on the gear oil brand for it.

I use Valvoline 75W-90 GL5 advance full synthetic gear oil in my 2015 RX350 AWD rear differential.

Like mentioned above make sure you can open the fill plug first before you drain. The fill/drain plugs can get seized and can be rounded out on these units.

 

Thanks will use Toyota 75w85 LT as transfer fluid mainly because 3RX requires a GL-5 fluid and the LT starts out with thin viscosity which should work in cold weather. Won't be towing anything so Red Line 75w90 gear oil gets first try in rear diff but any noise and will walk that up to RL 75w140.

 

You can not go wrong with Toyota 75W-85 LT as that is what is spec by the factory.

I just used Valvoline GL5 75w-90 in both units(transfer-case and rear diff) for convenience. Both the 75W-85 and 75W-90 start off as 75W for better cold flow while the 75W-90 becomes slightly thicker when warmed up. I am sure there is not much of a difference in oil viscosity from a 85 to 90 weight oil at operating temperature. I may have lost maybe 1 mpg(if even that much) from using a slightly thicker oil in my units due to some additional drag.

 

I recently changed the rear axle and transfer case lube and used mobil 1 75W 90. It’s been 1000 miles with no issues. It’s hard to beat the Amazon price of $27.50 for 2 quarts. You’ll still have about half a quart left. I’ve used mobil 1 75W 90 in my Sequoia, my son‘s 4Runner and a couple of 4th Gen 4Runners I owned, never an issue. I’m not trying to say Mobil is the best product on the market, but it’s a high-quality synthetic that will provide good service with regular change intervals.

 

Mobil 1 and Valvoline are my two top oil brands and my first choices for engine and gear oil. I may use different more exotic brands(Triax,Motul,etc) for cars that need unique gear/engine oil types and weights.

However, I tend to go with Valvoline as my first choice since the company make excellent oil products that are priced right.

 

This stuff is EXPENSIVE!

Just refilled my Tundra rear diff (not same vehicle, but same idea) with Redline 75-85 GL-5, purchased from Amazon. About $25/qt.

 

If I really just had to use a 75W-85 gear oil in my RX350 I would just use Triax 75W-85 gear oil. Good fluid that works well and is affordable. I use Triax in my 2020 Alfa Romeo transfer-case that calls for 75W(or 75W-80) gear oil.

 

I just did the rear differential fluid change on my wife's 2010 with 155K miles.
I used Toyota 75W-85 GL5 (metal can). It took me a while to get this from Toyota.

I still need to do the front gear which might be a bit difficult since the plug is located in a tighter space (for the fill)

 

To put my two cents in

Factory recommendations:
- API Category GL-5
- Visc: 75W-85
- Trade Name: TOYOTA Genuine Gear Oil LT

I used Motul MOTYLGEAR 75W85 in the front and rear differential.

Toyota would be better; it's an expensive PAO full synthetic. Motul is a hydrocracking (semi-synthetic). Motul can be used if the vehicle is operated under normal conditions without heavy loads. If you constantly put it under load (off-roading, towing a trailer), then the original is better.

 

Thanks Alex, do you think the Lexus Toyota LT 75w85 gear oil recommendation is more about meeting CAFE standards rather than long term transfer and diff hypoid gear protection and wondering if a thicker GL-5 such as 75w110 might better protect the gear sets if for heavy daily use on ice roads for example. I've been using Red Line GL-5 75w90 which gets a bit of winter use up a couple of hills but will likely change that out next fall, don't expect awd system will see any use during the summer.

 

The fact that Toyota (and many other automakers) switched to 75w85 viscosity is 90% due to CAFE environmental standards and only 10% due to concerns about the hardware. As I discussed in another thread about low-viscosity motor oil, this is due to environmental concerns and competition between manufacturers in fuel efficiency, not to concerns about "thin" oil passages.

To prevent the hypoid gear from "eating" itself under load, the original oil contains a powerful package of extreme pressure additives and a high-quality PAO base (LT index).

If your vehicle experiences frequent slippage with sharp traction (shock loads on the teeth) due to icy roads, for example, or frequently towing a trailer or frequent mountain driving, it's better to use 75-90 oil. This will create a thicker oil film for better protection against shock loads. 75w110 is overkill and only suitable for trucks regularly used off-road or for commercial vehicles. You can use a 100% synthetic oil, such as Motul Gear 300 75w90 or similar products from Redline or Amsoil.

P.S. Car manufacturers don't want you to drive your car your whole life. Their goal is to make money. A car should last its warranty period without any problems. What happens after that is of no interest to them. Therefore, all oil specifications, change intervals, etc. are based on profitability and compliance with environmental regulations and standards.

 

I used Valvoline 75w-90 every 30K miles. Its good enough, there is nothing fancy about