80W-90 for the Rear Diff

I plan on changing the rear diff fluid in my '15 DC SR5 4x4 longbed. I visited the dealer today to pick up the gear oil. Parts guy said they use 80w-90 now in their service dept. Since the owners manual calls for 75w-85, should I be concerned with the switch? I live in the Garden State, and winters are not extreme.

 

Does that have the LS additive

 

Negative.

 

That’s the bottle they sold to you?
How much did they charge?

 

$17.20

 

Red Line 75W85 GL5 Limited Slip

 

I use valvoline synthetic gear oil 75w90. I live in cali no snow here

 

75W 140 Neo Synthetic hands down the best gear oil on the planet. PERIOD…

 

I have done two rounds of gear oil changes in rear axle of my 2007. The first at about 40K dumping the factory fill, which came out a bit dirty but nothing out of the ordinary considering the ring gear and pinion gear broke in with that gear oil. I put in Valvoline synthetic

$39 75W-90 GL-5 Limited Slip, Ultra Long Drain 500k Miles, Manual Transmission, Gear/Differential Lubricant (1 Gallon)

75W-90 at that time.

Fast forward to 139,000 miles or thereabouts and I dumped the Valvoline synthetic 75W-90 after feeling guilty about letting it go that long. I also did the transfer case and front diff at this time, as both of those had been done at about 40K and 60K respectively with factory fluids.

All of those fluids came out nice and clean, no metal shavings, no burnt odor, just amber colored gear oil. Still translucent. Probably could have gone another 100K from the look of it, particularly the full synthetic I put in the rear axle.

Long story short, you don’t need to over think this one. Buy a good full synthetic gear oil and put it in!

 

Is it now. How come?

 

What LS additives? Our trucks don't have factory LS nor need the additive package.

 

No offense, but I would rather spend the $ at Walmart or the parts store and get Mobil 1 or Valvoline Syn

$39 75W-90 GL-5 Limited Slip, Ultra Long Drain 500k Miles, Manual Transmission, Gear/Differential Lubricant (1 Gallon)

75W-90 for the same or less money. That off brand gear oil wouldn’t go in anything I cared about.

The Valvoline Syn ez pour bags are good for refilling the diff, no pump required.

 

Jesus $17 for that crap. You can get nearly any brand of your choosing synthetic for that price. I would return it and find something else, not from the dealer.

However I wouldn't worry at all about 80w-90 vs 75w-85 so long as it meets the oil requirements. And as VWTim mentioned, no limited slip additive is necessary.