Diff and transfer case fluid replacement

Sorry if this has been asked before but, I'd like to know what everyone's choice is for gear oil in the diffs and transfer case when you service it.

I've read a few things about the OEM fluid for the transfer case and it's not only expensive, but also hard to get from the dealer.

Any thoughts or words of wisdom on this? And also the part number(s) for the fill and drain plugs that aren't the allen key type. I believe it's the Lexus ones that most have used, if I'm not mistaken.

My ride is a regular ol' 1998 SR5 4wd 4Runner.

Thanks,
Larry

 

I picked up some "Mag 1" from the dealer.

 

Whatever meets the spec in the manual will beat whatever’s in there if it’s been a while.

 

Several lube producers make great gear lubes. Check the specs for your year & model. Note some GL-5 are good for diffs, but not for transfer case which generally like GL-4 lubes-at least on 5th gens.

 

The transfer case in your regular ol' 1998 SR5 4WD 4Runner uses regular ol' 75W-90 gear oil.

 

Thanks for all the input! I appreciate it.

 

ive heard the diff fluid is VERY expensive from the dealership. I use the redline synthetic - i think i pay 90 from Amazon. But yeah, as others have mentioned you can use valvoline or Mobil 1. I think they both come in those squeeze bottles to make life easier. I bought this and it is a game changer. Makes life so much easier doing the trans, diff and transfer case

$54 Orion Motor Tech Transmission Fluid Pump, 3L Transmission Filler Pump with 12pc ATF Aluminum Adapters, Manual Transmission Fluid Transfer Pump with Pressure Gauge, Transmission Dispenser Oil Pump Tool

https://www.amazon.com/dp/B0CN1B2J5Q

 

Check out https://goldplug.com/

 

That's a nifty piece of gear there! I like it! Anything to make life easier is a plus in my book!

 

I like that GoldPlug replacement too. I'll put that on the list as well. Thanks!

 

Another follow up question for you fellas...
OK, this past weekend I went and changed out both the diff fluids as well as the transfer case. It wasn't a bad job for the most part...aside from when I was refilling the transfer case and the hose decided to "leave the pump" and gave me a small bath.

The front diff fill plug didn't want to play nice and come off. So I ended up cleaning it off a bit and hitting it with some PB Blaster. I let it set for a while and tried to crack it loose. My 10mm on a 3/8 drive breaker bar wasn't going to do it by itself. So, I found an old piece of conduit that happened to fit it nicely.

A little bit of muscle and there was a loud pop. I thought I had broken either the 10mm and/or the plug itself. Luckily for me, it broke loose.

My question now is pretty simple...

From what I have read here, it's said for diffs, the interval is around 30,000 miles or so. Now, is that for regular diff oil or is that for synthetic? Or both?

Thanks!