Best rear Dif fluid to use

Gonna change my rear differential oil this weekend on my 05’ DC 4wd. Any opinions on best one to use? It’s probably never been changed (175k miles) also hope to do the front and transfer case oil as well. Btw I live in Florida so not cold here.
I feel like I need to change the tranny as well (due to age and miles) but it shifts butter smooth. I do drive like a old man and never tow. All opinions and suggestions welcomed.

 

$39 75w-90 GL-5 Limited Slip, Ultra Long Drain 500k Miles, Manual Transmission, Gear/Differential Lubricant (1 Gallon)

75w-90 for your truck as well? Valvoline or Mobil 1 Synthetic. You may need an additive if it’s limited slip.

 

I like/used Royal Purple. You should be

$39 75W-90 GL-5 Limited Slip, Ultra Long Drain 500k Miles, Manual Transmission, Gear/Differential Lubricant (1 Gallon)

75W-90 for all 3. 6qts should do it.
Rear - 3.7qts
Front - 1.1qts
Transfer - 1.3qts

Obviously I would just fill till it starts dripping out the fill plugs. Get new washers and make sure you can remove the fill plugs before you remove the drain plugs. I believe it's a 10mm hex for the front diff plugs and the transfer case as well.

 

@Haggis777- it has been a little bit, but isn’t the ravenol 75w for the transfer case?

I used the redline

$39 75w-90 GL-5 Limited Slip, Ultra Long Drain 500k Miles, Manual Transmission, Gear/Differential Lubricant (1 Gallon)

75w-90 for the diffs.

though he is talking about a first gen here so can probably use 75w-90 for all three.

 

Rear diff fluid is 75/90, I used Royal Purple synthetic which I got on sale for 12.99/qt. Took 3 or 4 qts for the rear, 2 or so qts for the transfer case and 2 or so for the front diff. Think I bought 7 or 8 total but it's been awhile so don't quote me there. I would do all three if they've never been done, but my transfer case and front diff looked like new fluid when I drained it. The rear looked and smelled like crap. Old dino oil was in there. The synthetic fluids do not suffer the same thermal breakdown issues as the dino oil. Much better at long life use and only need to be replaced if they get water in them or get dirty.
Transmission can be drained and filled resulting in about half the fluid getting swapped for fresh. It's harmless and keeps the transmission with a fresh supply of additives. They are "sealed" in that they are not exposed to air, or combustion and thus the fluid doesn't so much get dirty as it suffers from thermal breakdown over time. Your 05 with the 5 speed is also sealed in another sense I believe. The process to exchange and refill the fluid is much more tedious than a drain plug and a refill through the dipstick (which yours does not have). Should you mess with the transmission fluid in a sealed transmission? let the debate begin. If it's my truck, I would. I would be leery of a transmission flush at 175k if it's never been done and you are not experiencing problems. If it's my truck, I would not personally do that.

 

@KNABORES lol yeah wasn’t trying to open a can of worms on that question. I’ve heard both camps arguments. That’s why I added mine shifts butter smooth.

 

Rear Diff is Spec’d 80w-90 (or straight 90w if you could get it anymore) on the 2002. Not sure about 2005.

Transfer and front diffs are

$39 75w-90 GL-5 Limited Slip, Ultra Long Drain 500k Miles, Manual Transmission, Gear/Differential Lubricant (1 Gallon)

75w-90.

 

FWIW the guys at East Coast Gear Supply discourage use of synthetic gear oil. They may not be the end all be all, but I imagine they do know what they are talking about. I use Lucas Dino oil which doesn't require an LSD additive.

https://eastcoastgearsupply.com/files/PDF Files/ecgs-gear-oil-recommendation1.pdf

 

^ the Toyota LSD calls for dino oil. I also run Lucas in mine.

Somebody posted some test results that didn't go well for royal purple (or Lucas Synthetic) but I don't know how much those tests relate to real world use. Those tests favored Valvoline and Mobil did okay.

 

huh weird...I thought I remember reading to use Royal Purple and thats what I did. Been fine for about 11K miles so far.

 

You must have red that in the Turd Gen Section. I’d drain and re-fill with Lucas.

 

haha.

 

I ran Royal Purple in my front Diff and T Case for a few years without issue but they specifically called it out as the worst.

 

yeah i saw that too...

dammit.

 

I've never been a fan of them, mostly because I think the purple is a gimmick, but to be fair I never used it either.

Not the same results posted before, this is data from Amsoil so possibly biased. I guess I'm confusing valvoline for Castrol, but Royal and Lucas did pretty bad here. Again, not sure how much this data relates to real use.

http://ultimatesyntheticoil.com/stop-differential-failure

 

@CodyP I'm sure running R.P won't hurt anything for a while. I would just make a point to use something else next time. They said the best approach is to just change the fluids regularly.

 

yeah, maybe I'll change at 15K instead of the 30K this time

 

i've put royal purple in my quad diffs since 2013.
Lucas oil from here on out.

 

I agree with @FirstGenVol that the most important thing is frequent changing. I only run Lucas because its hard to find dino oil in the 80-90w. If I were going synthetic I would go Amsoil or maybe Redline. I run Amsoil in my GTI transaxle, it started shifting like butter after the first day.

I'm not sure why Toyota recommends dino for the LSD. I know it has to do with the clutches but I can't think that a synthetic fluid can't mimic a dino fluid for that.