Fluids! Clear the confusion. What are you using?

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Tonyv__

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So I’m no stranger to this site but I don’t have a formal intro for myself. My current fleet consist of a 2008 Chevy express 3500, 2015 Yukon Denali, and 2018 Mercedes’ CLA 250. These are my first ever “long term cars” prior to this I’ve never owned a car long enough to have to service anything other than oil! I’m 30 years old and recently bought a house, got married, and started a family. So the changing of cars has officially stopped. I’ll be riding out these vehicles for the foreseeable future..


So now what I really came for. My 2015 Yukon is due for service. I’m at 63k. I’m ready to change all the fluids in the drivetrain.

MOTOR OIL - I’ve been using Amazon brand full synthetic 0w20 and a wix filter for every oil change. I was weary about using amazon brand but some videos and research show that it is absolutely comparable to the high end brand name oils..

TRANSMISSION/ TRANSFER CASE FLUID - i was checking out valvoline dexron vi (blue bottle) but I came across the AC delco dexron vi for a steal of a deal so I intend to use that.

GEAR OIL - here lyes some confusion. The owners manual says for front diff to use 80w90 gear oil (no mention of synthetic). Rear gear oil 75w90 synthetic.. but no matter where I look the 80w90 doesn’t show as compatible for my Yukon. Rock auto doesn’t offer it, Amazon doesn’t show compatible, every video I watch says they use 75w90 in the front diff. I’m sure the slight difference in weight doesn’t hurt but I’m torn to follow what I see all over the internet or what the actual GM manual recommends…


So if y’all wouldn’t mind helping me out and steering me in the Right direction that would be awesome.

And what brands do you guys prefer?
 
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Tonyv__

Tonyv__

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my confusion mostly was with the front diff information. The book says 80w90 but I can’t find any videos tutorials or websites that recommend 80w90 for the front. It’s all 75 90. Wondering if GM changed specs after a couple years?
 
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Tonyv__

Tonyv__

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Ok first I thought maybe I’m looking at the wrong website. But this is my book that came with the truck

C9A4DE51-B8CD-43B5-85DC-7F407ECE05B0.jpeg
 

Fless

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The one I pulled online says it's the 4th Printing. May the Fourth be with you.

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What's yours?
 

CMoore711

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The one I pulled online says it's the 4th Printing. May the Fourth be with you.
I see what you did there...

FWIW I used 75W-90 Gear oil in my front and rear diffs. Amsoil Severe Gear.
 

2006Tahoe2WD

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I'm thinking a GL-5 75W-90 vs. 80W-90 is not a significant difference. It would be interesting to find out why they spec'd 80W-90 vs the much more available 75W-90.
 
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