Yukon gears: increase viscosity when towing?

72c10

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Greetings all! I just had a thought and I emailed Yukon gears for their thoughts. I didn't get a straight answer.

I had 4.56 Yukon gears installed about 8 months ago. We bought a 1400lb/1700lb loaded pop up camper that I've hauled twice since we bought it. These 4.56 gears pull awesome w/ 33's.

My question that dawned on me last night. Should I put an 85/140w gear oil in the rear diff? I'm saying 85/140 because Yukon states to use conventional 80/90 in their gears. I emailed them with the question/situation and the response was "Weight / viscosity is dependent on load / heat 85/140 wont cause any harm, other than being thicker and using more energy to churn thru.".

Maybe I'm weird and too inquisitive, but I didn't feel he/they answered my question of what they recommend if I towed. Am I overthinking this diff oil weight subject? Should I leave the 80/90w conventional that's in there?

I hope all of you are enjoying your summer and your Jeeps!
 
That much weight is nothing, I've pulled and hauled over 3 times that in my Dually with 80/90w. The Dually even weights about 7,000 lbs empty which is more then your jeep and trailer together.
 
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I took their answer as : 80/90 is fine if you want to run 85/140 that's fine also it is thicker and will take more power for the gears and stuff to move thru
 
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That much weight is nothing, I've pulled and hauled over 3 times that in my Dually with 80/90w. The Dually even weights about 7,000 lbs empty which is more then your jeep and trailer together.
I took their answer as : 80/90 is fine if you want to run 85/140 that's fine also it is thicker and will take more power for the gears and stuff to move thru

Much appreciated for your responses. Makes me feel better, especially with BlackJKU's use of 80/90 with the dually. I just wanted to make sure I took care of those diffs. Probably the best money I've spent on this Jeep. I'll keep that 80/90w in there. Maybe I'll swap out to a higher weight when it's time but I'll leave it til it needs to be swapped out.
 
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Much appreciated for your responses. Makes me feel better, especially with BlackJKU's use of 80/90 with the dually. I just wanted to make sure I took care of those diffs. Probably the best money I've spent on this Jeep. I'll keep that 80/90w in there. Maybe I'll swap out to a higher weight when it's time but I'll leave it til it needs to be swapped out.

The only problem with the higher weight is in the winter time if it gets real cold.
 
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The only problem with the higher weight is in the winter time if it gets real cold.
Thats very true. And I won't be. A camping in the winter here. I could always just swap out though, since it's quick and relatively inexpensive. I think after speaking to you guys, I may just leave it.
 
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Thats very true. And I won't be. A camping in the winter here. I could always just swap out though, since it's quick and relatively inexpensive. I think after speaking to you guys, I may just leave it.


Also I used to work on Offroad equipment and also Semi's and they all used 80/90w. Your trailer doesn't weigh that much to worry about.
 
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