Differential fluid for 140k 2004 tundra 4wd?

I've been asking local mechanics and they don't know the answer. I've tried calling the dealership where my truck was purchased from but they haven't returned any calls all week about this question.

I recently replaced a bad axle and while doing so I lost a decent amount of differential fluid. Im not too sure what to use to top off, and since I'm sure it hadn't been changed in years im just going to go ahead and replace the front rear and transfer. Not sure what I should be using though.

EDIT: just got off the oil with the dealership and its 75w90 GL5. still pondering over what brand to get. I do a lot of off roading and occasional towing.

 

LSD or non-lsd?

If LSD I would recommend Motul 90pa. LSD's work best with non-synthetic oils and friction modifier.


Non-lsd any synthetic

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

75w-90. Or if your worried about heat from towing you can do a 75w-140 synthetic.

 

Just check and I have LSD

 

www.amsoil.com will tell you capacity and weights you need.

 

LSD here. Why this oil? I need to do this soon.

 

It's non-synthetic, it is the right 'weight' and of the 15+ oils I've tested for both grip (lockup) and chatter (parking lot turns) it was the best. It has the proper amount of friction modifier in the fluid already. Just enough that the LSD still works great.

Clutch type LSD's don't work as good with synthetic oils. And thats why all the aftermarket LSD's do not recommended to use it with them.

I've tried oreilly/kragen, autozone, napa, walmart brands; also valvoline, mobil, amsoil, redline, etc. All of those in various weights, synthetic and non-synthetic and with/without adding friction modifier.

This was done on my Cusco RS 2-way LSD, which is much better than the OEM.