2012 Yukon XL Denali fluids and such

[MASTERBrian]

I picked up a 2012 Yukon XL Denali last October. She has about 80k miles and I'm wanting to go through the fluids, just to update them and insure everything is up to spec. I know I'll be ahead per the book on a few of them, but I have no clue how the previous owner treated everything and so forth, though the truck does have good service records for oil and such.

That said, I have 2 qts of BG Products SAE 75W-90 Full Synthetic Gear lube. I plan to use that until I'm out of it, I'm not sure how much the front or rear diff take. I've used and liked Royal Purple in the past and figure I'll top off with that. Any issue with either of those for this? I think I saw the front had a drain plug, I'm not certain. If not, do I buy a gasket to close back up or just RTV it? Same question on the rear? I've been told on my 2003 burb some like the gaskets some say just RTV.

The Transfer Case says Dexron VI Auto Trans fluid in the manual....this is the All Wheel Drive. Does that sound correct? I think it does have a drain plug and I actually worry there is a whine coming from here. Any idea what that might be? I plan on taking her to the Transmission shop for a filter and fluid change. I know this is not called for until 156,000 miles, but I feel these are weak points in the GMC/Chevy product. Every single one I've owned has needed these items replaced by 180k-200k miles. No clue what the maintenance was on them.

Any tips beyond this??

[MJN]

I use AMSOIL for everything and they have a great lookup tool that will tell you the proper grade and amount of fluid needed for your Yukon XL. They also have filters.
https://www.amsoil.com/lookup/auto-and-light-truck/

Feel free to PM me with any questions as well.

The front should have a drain plug, I always make sure the fill plug comes out before draining anything out. No point in draining it and then finding out the fill plug won't come loose.

[Greenlee]

I bought a 2012 AWD Denali a couple of years ago. It had 54k when I got it and I’m up to about 88k now. I had all the fluids changed at the dealership at about 75k. I really like the truck! Best driving truck I’ve ever owned and I love the rumble of the 6.2.

[truckdude239]

i use Valvoline tcase fuild covers everything from gm auto trax fuild to dexvi for trasnfer cases

[MASTERBrian]

Originally Posted by Greenlee

I bought a 2012 AWD Denali a couple of years ago. It had 54k when I got it and I’m up to about 88k now. I had all the fluids changed at the dealership at about 75k. I really like the truck! Best driving truck I’ve ever owned and I love the rumble of the 6.2.

I love the rumble as well!!! It drives great on highway, but seems to have a whine, not sure where coming from, having trans serviced Tuesday, I'll ask him about and I think maybe a wheel bearing having issues. But I love how you can't feel the wind when driving!!

[MASTERBrian]

Originally Posted by truckdude239

i use Valvoline tcase fuild covers everything from gm auto trax fuild to dexvi for trasnfer cases

I'll see if I can find that. Want to service T case before going to trans shop.

I'm done dealing with the dealership I bought it from. They overfilled the oil and overinflated the tires and though promised me a 2nd remote they passed off a junk aftermarket one.