Clarification on transfer case and differential fluids (1 Viewer)

[drowzyGX]

Hey Y'all,

There's more than a handful of threads that discuss the fluids for the transfer case and front/rear differential fluids. However, the info I've found in them conflicts with what I see in my owner's manual (page 552), and I just want to confirm that I'm using the correct fluids before purchasing and changing them next weekend.

My owner's manual recommends:

• Front / Rear differential
  • oil type: Hypoid gear oil API GL-5
  • oil viscosity
    • above -18 C / 0 F: SAE 90 or SAE 85W-90
    • below -18 C / 0 F: SAE 80W or SAE 80W-90
• Transfer
  • oil type: Hypoid gear oil API GL-5
  • oil viscosity: SAE 75W-90

Amsoil's website:

• Front / Rear differential
  • oil type: GL-5
  • oil viscosity
    • above -18 C / 0 F:
      • SAE 80W-90 Synthetic Gear Lube (AGLPK)
      • Severe Gear 75W-90 (SVGPK)
      • Severe Gear 75W-110 (SVTPK)
    • below -18 C / 0 F:
      • SAE 80W-90 Synthetic Gear Lube (AGLPK)
      • Severe Gear 75W-90 (SVGPK)
      • Severe Gear 75W-110 (SVTPK)
• Transfer
  • oil type: GL-5
  • oil viscosity:
    • SAE 80W-90 Synthetic Gear Lube (AGLPK)
    • Severe Gear 75W-90 (SVGPK)
    • Severe Gear 75W-110 (SVGPK)

The reason I linked Amsoil, is that it seems to be pretty highly recommended across the various forum threads that Google returned (here, clublexus, and some other boards). Mobil 1 also got some solid endorsements.

I've never changed diff or transfer case fluid before, and I don't want to mess anything up on this car.

Should I ignore the Amsoil recommendations, and just go with what's in my owner's manual? Is there a reason Amsoil recommends 3 different viscosities? Thoughts on the "liquid gold" Toyota Gear Oil LF 75W for the transfer case? The handful of toyota dealerships near me said they can order it, but don't keep it in stock and wouldn't use it on my car if they changed the fluids. I don't mind paying the ~$130 for two 1L cans if it's the right way to do this job. Trying to make sure I do this the right way as I want to avoid any potentially costly repairs to the transfer case or differentials.

Thanks!

 

[CarolinaGX]

I did similar research last summer. I went with Royal Purple 75-90 in the transfer case and Mobil1 75-90 in the diffs. This is what the Lexus dealer told me to use (weight, not the brands).

 

[drowzyGX]

I did similar research last summer. I went with Royal Purple 75-90 in the transfer case and Mobil1 75-90 in the diffs. This is what the Lexus dealer told me to use (weight, not the brands).

hey Carolina, thanks for the info! any particular reason for 2 different brands but the same weight? Apologies if that’s a dumb question - all this maintenance is brand new to me.

 

[GXO]

I use 75-90 across the board

 

[z00t3ch]

6-quarts SuperTech or Mobil1 75w90 synthetic. The "golden Toyota" fluid is for the newer GX460 transfer case made by a different manufacturer (Borg-Warner). I used Ravenol 75w90 in my transfer case and Mobil1 in my diffs.

 

[drowzyGX]

I use 75-90 across the board

hey dan, assuming you haven’t had any issues with the lower viscosity oil in the differentials?

maybe a stupid question, but what would be potential risks / benefits of running 75w 90 as opposed to 80w 90 or 85w 90 from the owners manual?

 

[CarolinaGX]

Mobil1 is half the cost of Royal Purple. The diff is pretty unique so I wanted to be sure I used the best option I could readily find. The diffs are very basic and I have had good luck with M1 for decades so I stuck with that for the diffs. Amsoil, Mobile1, RP, Valvoline, Castrol, are all reputable brands and as long as the specs are correct, you will be fine. 75-90 for all 3.

 

[drowzyGX]

Mobil1 is half the cost of Royal Purple. The diff is pretty unique so I wanted to be sure I used the best option I could readily find. The diffs are very basic and I have had good luck with M1 for decades so I stuck with that for the diffs. Amsoil, Mobile1, RP, Valvoline, Castrol, are all reputable brands and as long as the specs are correct, you will be fine. 75-90 for all 3.

Dang, you weren't kidding. That Royal Purple is pretty pricey. I may go ahead and snag that for all 3, though, since it's a once every 30k miles or so change.

 

[z00t3ch]

Royal Purple never tests as well as Mobil1 or Amsoil, lot of extra dough for less actual go...

 

[ArBrnSnpr]

Amsoil and Mobile 1 have always been my go to. Years ago I tried Royal Purple and Redline fluids in an M3 diff and the clutches didn't seem to do as well with it. I tried RP again in my Jeep tranny (it was born that way) and after a few thousand miles it shifted rougher than the M1 it had replaced did. I don't waste money on either brand anymore.
It's a good thing too because during my regear and subsequent pinion bearing failure, I pulled the diff 3 times and changed the fluid each time. That would have been pricey at $20/qt.

 

[CarolinaGX]

The reason I used RP in the TC is because it was listed as "Warranty Compliant"

I believe these trucks came from the factory with Dino oil instead of synthetic which is the reason for the 30k interval. I plan to do it every 50k because it is easy to keep track of. Although, I know I will have my diffs out in the next year or so for gearing so I guess it doesn't really matter.

 

[GXO]

hey dan, assuming you haven’t had any issues with the lower viscosity oil in the differentials?

maybe a stupid question, but what would be potential risks / benefits of running 75w 90 as opposed to 80w 90 or 85w 90 from the owners manual?

I responded too quickly. I also add some shockproof redline heavy duty to my diffs. I get a quart and split it front and rear.

 

[drowzyGX]

Hey Y'all,

Really appreciate the advice and input! I'm gonna go ahead and snag mobil 1 75W-90, and use it across the board.

I took my car today to get the transmission fluid changed (didn't want to do that one myself). Asked the shop manager his thoughts on the fancy pants Toyota OEM fluid, and he said pretty much the same as y'all: 75W-90 across the board. He also suggested mobil 1, as that's his preferred brand.

After seeing so many recommendations for both mobil 1 and amsoil, I'll go with mobil 1 for now since I can snag it pretty much anywhere.

Y'all probably already knew this...but today I learned what the viscosity labeling means. So the 75W-90, 80W-90, and 85W-90 oils will all operate with the same viscosity at high temps. It's just the lower temps where they'll be different. Makes sense why 75W-90 across the board is fine then, even with the manual suggesting 80W-90 or 85W-90.

Y'all have been incredibly helpful for a complete automotive novice like me. I'm learning a lot!

 

[z00t3ch]

Y'all probably already knew this...but today I learned what the viscosity labeling means. So the 75W-90, 80W-90, and 85W-90 oils will all operate with the same viscosity at high temps. It's just the lower temps where they'll be different. Makes sense why 75W-90 across the board is fine then, even with the manual suggesting 80W-90 or 85W-90.

To add to the confusion and fun, gear oils are rated differently than engine oils. A 20w50 engine oil is roughly the same viscosity as 75w90 gear oil, and are interchangeable in certain Harley applications.

 

[drowzyGX]

Hey y’all,

finally got around to changing the rear diff fluid today. Took a while because the fill plug just did not want to come out.

manual says the rear diff needs 3.3 quarts (and that’s about what it took before fluid started to drip out the fill opening). However, only about 2 quarts drained out. the drain plug didn’t have any metal on it - was a little grimy, but, all in all, pretty clean.

should I be worried about the amount of fluid that was in there?

doing the front tomorrow, and really hoping that close to 1.5 quarts drains out.

 

[Matsui]

Based on the comments here, I'll also get Mobil 1 75W-90 for TS and R/R diffs. How many total quarts should I get for all 3?

 

[Tanner H]

I keep this link bookmarked for reference. Has all the info you need.

Driveline service

Also, tread lightly on the front diff drain plug... Seems like the torque specs are too much for the 10mm allen key hole and they strip. Ask me how I know.

Theres a solution to it and I have it on my truck. Works great now without the fear of stripping. The plug below actually has a 14mm hex on it (as opposed to the inferior 10mm allen hole)...so you can put a 14mm socket or box wrench on it without fear of stripping.

2-PC KIT GENUINE LEXUS (2006-2021) DRAIN PLUG & GSKET 90341-24016 & 90430-24003 | eBay

It fits: LEXUS: GS460 (2009-2011) / IS250/IS350 (2007-2016).

www.ebay.com

 

[sandcruiser]

I keep this link bookmarked for reference. Has all the info you need.

Driveline service

Also, tread lightly on the front diff drain plug... Seems like the torque specs are too much for the 10mm allen key hole and they strip. Ask me how I know.

Theres a solution to it and I have it on my truck. Works great now without the fear of stripping. The plug below actually has a 14mm hex on it (as opposed to the inferior 10mm allen hole)...so you can put a 14mm socket or box wrench on it without fear of stripping.

2-PC KIT GENUINE LEXUS (2006-2021) DRAIN PLUG & GSKET 90341-24016 & 90430-24003 | eBay

It fits: LEXUS: GS460 (2009-2011) / IS250/IS350 (2007-2016).

www.ebay.com

I find this really amusing because I remember the Landcruiser enthusiasm not-so-many-years ago when everyone was really excited to finally get rid of the lousy hex-head drain plugs on differentials and replace them with fancy new 10mm allen key plugs that were harder to strip. I suppose that each have their advantages... and that the grass is often greener.

 

[Tanner H]

Could be. As a gx470 and 100 series owner, the allen diff drain plug on my 2000 Land Cruiser seems way more stout than the gx allen plug.

 

[Auzz]

Hey Y'all,

Really appreciate the advice and input! I'm gonna go ahead and snag mobil 1 75W-90, and use it across the board.

I took my car today to get the transmission fluid changed (didn't want to do that one myself). Asked the shop manager his thoughts on the fancy pants Toyota OEM fluid, and he said pretty much the same as y'all: 75W-90 across the board. He also suggested mobil 1, as that's his preferred brand.

After seeing so many recommendations for both mobil 1 and amsoil, I'll go with mobil 1 for now since I can snag it pretty much anywhere.

Y'all probably already knew this...but today I learned what the viscosity labeling means. So the 75W-90, 80W-90, and 85W-90 oils will all operate with the same viscosity at high temps. It's just the lower temps where they'll be different. Makes sense why 75W-90 across the board is fine then, even with the manual suggesting 80W-90 or 85W-90.

Y'all have been incredibly helpful for a complete automotive novice like me. I'm learning a lot!

Would it be fine to put 85w90 in the transfer case? I live in a hot desert climate