I am planning on changing the oils in both diffs and my T case in the next few days. Couple questions...

Can I use the same oils for both diffs and the t case (just want to make sure)? And what are some weight suggestions? I have heard a lot of differing opinions. I am thinking about 75w-140 because I have some whining noise from a diff or the t case. No vibrations or grinding so I believe the oil will fix it. Thoughts?

 

I use 85/140w in TX. Up north I’d do 80/90w

 

Thanks! That should save a little money.
Does synthetic vs. mineral based matter? Does it last longer or have more quieting abilities?

 

I use dino oil in the diff/TC vs synthetic.

 

Factory oil is synthetic, I would not replace it if it has less than 200k on it. I will bet the price of the oil analysis that it would show the viscosity is still within the factory specification range and contaminants are minimal. I started draining a 109k mile Disco and the oil looked new, immediately stopped and put the plugs back in.

Of course, as you can see in another thread I have a 230k mile Disco with now issues.

 

I’d certainly inspect the diff oil & TC wise those fella’s seep pretty good & they DO NOT like to be driven dry (just ask my 500.00 03 D2’s original TC). Any GL5 rated gear oil will be fine. Older RRC/D1’s didn’t use full synthetic back in the day. With the way they seep dino works fine. I’ve never put the $$ stuff into any of my LR’s except the LR3’s rear locking diff.

 

I've got Redline 75w-90 in mine. I changed it at 60k miles. No leaks or any whine.

 

I know those diffs and t case are pretty tough, but I also know what happens when they are low on oil or dry. I am wondering if it would get too cold for me to run 80w140. This is my first diff and T case change as a new disco owner. I want to feel out all my options. I've always been a fan of dino oil... mostly because I can't afford the synthetic haha.

 

If you’re in a cooler climate 75/90w or 80/90w.

 

I change all my fluids every year, yes even my brake fluid.

Most think its overkill...doesnt matter to me, I'd rather have the piece of mind.