Downside to running 75w-140

[HawkeyeScott]

Wondering if there is any downside besides the initial investment. Towing some now (2000 lb.) travel trailer up some decent sized hills and mountains here in the West with my 2000 Durango 4.7. (Never too quickly, I might add.)

Have a syn blend 75w-90 in the rear end now but really considering a switch to some Mobil 1 75w-140 before we make a long, potentially hot tow of about 350 miles in a few weeks. Will see some more steep inclines.

Winter time temps can dip to the single digits. Summer towing can happen in 95-100 degree temps.

Any reason I shouldn't go with the heavier duty stuff? It'd be about a $50 job.

Thanks a lot.

 

[Inspecktor]

My 2006 Dakota 4.7 with tow package requires 75W-140 for any towing.

 

[Colt45ws]

A few % loss of fuel economy. Unless you have exceptional logs and always drive the same routes, you will likely never notice.
I'd put the 140 in.

 

[CT8]

I run 75w-140 in everything . I don't see a mpg hit though I am sure there is a tenth or so loss maybe?

 

[MolaKule]

A viable alternative are the 75W110's from the likes of Redline, Amsoil, and Lubrication Engineers.

 

[HemiHawk]

My 97 jeep (similar rear i think?) Requires 75-140 for towing also. I dont think there are really many downsides other than possibly minor fuel economy. but lets be honest your MPG probably isnt that great now haha.

 

[LeakySeals]

Wonder if the thicker 140 would quiet AWD front diff gears any. Would trade the mileage to quiet the whirring sounds

 

[HawkeyeScott]

Thanks, everyone. I appreciate the responses.

And yeah, the MPG hasn't been great. 11.5 the first 150 mile round trip. But I wasn't expecting to set any records. Nothing broke, we made it safely and gas is affordable right now. Can't ask for much more.

 

[zeng]

There is no reason you shouldn't go heavier.......
At your winter temp of single digit, one could go for an 80W140 of lower VII content which may even preempt potential gear whining in times to come, though speculative.
Fuel economy difference in differentials ......... often an exaggeration in Bitog, I suppose.
JMHO

 

[meep]

some have mentioned the higher VI oils don't transfer heat as well. IDK.

2,000 lbs is not a lot. is it a pop up? pop-up has minimal front area and I really can't see how it would stress something as big as a durango. I used to pull a 2500lb pop-up with a 3.3 T&C minivan with the troublesome 41TE-- never had any issues.

 

[HawkeyeScott]

It's a 16 ft. camp trailer. Just a hollow box but it does have a lot of wind drag. On the flat, the Durango seems perfectly fine. Up any grade, it definitely is working the truck.

 

[Y_K]

Extra heat, I wouldn't care about mpg side of the equation