Used 75/90 instead of 80/90

Joined
Sep 28, 2007
Messages
101
Location
Anchorage Alaska
I filled my front diff with Amsoil 75-90 instead of 80-90. Do you thin t his will make a heck of alot of deffernce? Should I drain it or continue to run it. Going on a 7k road trip in December and just getting a head start on th e fluid changes now. Thanks for the advice,
 
Joined
Dec 21, 2003
Messages
12,385
Location
Northern CA
Based on viscosity only, the 75W will be a bit better than the 80W where you are and they will both be the same at high temperatures. You did good. The fact that it's a high quality synthetic is a plus. It would be hard to beat for your application.
 

AFmedic

Thread starter
Joined
Sep 28, 2007
Messages
101
Location
Anchorage Alaska
I'm going to be driving from Anchorage to Georgia in December, with such a long drive do you think there will be any added benefit to using 80-90. Once I get there and start enjoying the nice and hot Georgia temps would you change it then?
 
Joined
Dec 21, 2003
Messages
12,385
Location
Northern CA
No change is needed or even desirable, the 90 governs at high temperatures and you are using a good synthetic. It would even be good in places that get real hot like parts of the SouthWest.
 
Joined
Oct 20, 2007
Messages
502
Location
Canada
Then it wouldn't concern me at all. I don't imagine you're planning on driving highway speeds in 4wd anyway.
 
Joined
May 27, 2003
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1,565
Location
Elkridge, MD
My Jeep calls for 80W-90 in the factory owner's manual, but the factory service manual calls for 75W-90. That's enough evidence for me to conclude it really doesn't make any difference. I run Mobil 1 75W-90 in both the front and rear diffs.
 
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