2014 Silverado: now using 75w-85?? Amsoil question

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Wife's 2014 Silverado just rolled 5k miles. I usually do a flush of the front and rear diffs and transfer case at this mileage for peace of mind. Apparently GM in a quest for CAFE standards is now using a proprietary 75w-85 GL-5 synthetic rear end fluid as opposed to the old standard 75w-90 grape juice. Any body know if the rear ends are carryovers from the previous years? I always use Amsoil SVG in both front and rears of my previous GM half tons. Should I stick with the 75w-85 GM fluid? Only other 75w-85 I can find is Redline but it's GL-4 so that a no go.
 
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Laramie, WY
that is awesome, cooler then a guy driving a truck. lol i couldn't image my wife in a truck, she is only 5 feet tall... But since getting her car she has become a somewhat of a bad[censored] driver though.
 
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Midwest, Illinois
Originally Posted By: 01_celica_gt
that is awesome, cooler then a guy driving a truck. lol i couldn't image my wife in a truck, she is only 5 feet tall... But since getting her car she has become a somewhat of a bad[censored] driver though.
OT, but my wife is 5'1" and she climbs right on up into the F350, drives to the storage area, hooks up the TT, and backs it into whatever campground she chooses. Now that is pretty BA, IMO. Back on topic, a syn 75w90 should do just fine.
 
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Am I wrong in thinking that 75w-85 just seems a little light for a pickup? Especially if you plan on towing with it? The rear differential in my truck and others that I have looked at always called for a 75w-140 or something similar in the rear. As for the fluid, Amsoil Severe Gear or Royal Purple Max Gear would do the trick. thumbsup
 

MolaKule

Staff member
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Originally Posted By: jk_636
Am I wrong in thinking that 75w-85 just seems a little light for a pickup? As for the fluid, Amsoil Severe Gear or Royal Purple Max Gear would do the trick. thumbsup
If the gear lube has the proper GL-5 additive package (which I would assume it does), I don't see it as too thin. New teeth hardening methods and tooth finishes allow a slightly thinner fluid. A 75W85 is primarily for the benefit of fleet CAFE figures. If you don't mind a very slight mpg hit, then my recommendation is to use a synthetic or a semi-synthetic in SAE 75W110.
 
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Quote:
Am I wrong in thinking that 75w-85 just seems a little light
An aircraft carrier uses 30 wt turbine oil in its 65,000 hp gears. It all depends on the design.
 
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