Diesel Place banner
1 - 8 of 8 Posts

·
Registered
Joined
·
841 Posts
Discussion Starter · #1 ·
I ordered some fluid for my rear diff. I got Amsoil 75w140 because I tow a lot of heavy stuff. I consulted George Morrison of AVLube and he said the 90 weight was better because it provided all of the protection I need and the 140 weight would have a risk of getting too hot. My manual does not suggest 140 weight at all under any circumstances. George said they only suggest 140 weight for off road vehicles never going over 30 mph. I trust George, just wanted to hear other experiences.

Also, the 140w will hurt mileage, I am pretty certain. SPICER
 

·
Registered
Joined
·
1,347 Posts
Ya, the 140 would just put a little more drag in it, using more power to move things. SHouuldn't be a heat problem though. The heat would be in the tranny or engine trying to turn it, but this is minimal. THe thicker the better with providing protection, but it comes at a cost, so finding the happy medium is key. The 110 would have been a good choice.
 

·
Premium Member
Joined
·
1,618 Posts
Ya, the 140 would just put a little more drag in it, using more power to move things. SHouuldn't be a heat problem though. The heat would be in the tranny or engine trying to turn it, but this is minimal. THe thicker the better with providing protection, but it comes at a cost, so finding the happy medium is key. The 110 would have been a good choice.
X2 on the 110 Severe Gear if you feel you need a little extra protection. I've run Amsoil 75W90 in my last three duallies (Severe Gear in my last two), and I pull anywhere from 12K lbs up to 16K lbs - sometimes 3K miles per month during the race season. I've never had any rear gear issues, and each time I change my gear oil, I inspect my ring and pinion, and they have always had ideal contact and no visible wear.
 

·
Registered
Joined
·
6,504 Posts
I had some of the 140 Amsoil in the garage and went ahead and ran it in my diff for a cycle, even though I don't tow very often or very heavy. I ran it from the Summer into the Fall and through the Winter with no noticable change in performance and mileage. One thing I did notice was that it came out crystal clear when I drained it and I think my diff really appreciated the extra lubrication. Bottom line - probably not necessary, but certainly shouldn't hurt if you've already bought it.
 

·
Registered
Joined
·
269 Posts
I run sever gear too... and the only thing i notice is that in cold weather that it seems have a very very slight restriction ... or it could be in my head too... but i am glad i am running it!
 

·
Premium Member
Joined
·
1,618 Posts
The 75W140 grape juice is all the dealers around here carry.
Heath is closer to you so shipping would be cheaper, but many of us, including me, can ship you Amsoil gear lube and oil. Don't feel you're stuck with or have to buy the dealer stuff.
 

·
Registered
Joined
·
363 Posts
I have run the 75w140 since my first change at 2,000 miles. I have changed it twice at 20,000 mile intervals and both times and it comes out very clean! I have run both GM "grape juice" and Mobil1 with great success.

The 75w140 will not hurt your fuel mileage but will provide great protection for your differential. Just my 2 cents.
 
1 - 8 of 8 Posts
Top