redline 75W140

Messages
1,426
Location
Golden Meadow, LA
It's time to change the oil in the rear end of my 2012 F-150 work truck that I recently bought. Its currently sitting at 156, 530 miles and I'm not sure if the previous owner ever changed it. its a 2wd with the 3.7 V6. I,m trying to figure out if its limited slip or not, giving the local dealer my VIN was no help. Anyway, Im considering running Redline 75W140 and changing it every 50-100k miles. I picked up a 4 oz bottle of the Motorcraft XL-3 friction modifier, in the event that it is limited slip, I'll have it when I'm ready to change it. Asssuming that the Redline already has the LS additive in it, will it hurt to add the XL-3? I plan on scraping off the factory silicone and using a Lube Locker gasket. It has a 10 bolt cover, would anyone know the torque spec? Would it be better to buy a gallon of Redline off Ebay or Amazon?
 
Messages
345
Location
WA
You can get both rear tires in the air, turn one tire & watch the other. If the other tire turns in the same direction as the one you're spinning, it's a limited slip unit, turns opposite, open diff. At least that way you will know if you need a friction additive..........
 
Messages
10,358
Location
Jupiter, Florida
A quick and dirty test is to rotate one rear wheel while in park (parking brake off) , and in the air. If the opposite wheel rotates the opposite direction, it's an open differential. If no rotation happens, it's a limited slip. The exception to this test is the rare Torsen differential, which acts as an open differential until power is applied and both tires have traction, then it locks up. You don't have a Torsen.
 
Messages
1,289
Location
Missouri
Check the axle code on the vin tag. Ford uses a letter as the first digit on limited slip and a number as the first on open differentials. The only exception is L it is used for the electronic locking. So examples 86 would be a 3.73 open diff b6 a limited slip 3.73 diff and L6 for a 3.73 with an e locker.
 

mobilaltima

Thread starter
Messages
1,426
Location
Golden Meadow, LA
My axle code is 26, so it appears I have a Dana 60, 3.55 gears, open differential. I'm not complaining, no limited slip additive to worry about. ls1mike, 75W140 is the spec'd fluid for my truck and most F-150s for quite a few years. I'd like to know as to why they use 75W140, versus most GM 1500, 2500 and 3500s calling for 75W90.
 
Messages
2,528
Location
pa
looking at the dana web site when i changed my frontiers drivetrain lubes shows they recommend a real synthetic 75-90 which redline is! the cheap OE Nissan lube is a 75-140 semi-syn for the nissan-dana 60 in it so i opted for the redline 75-90 + it requires NO xtra additives that could upset their chemistry. using all redline lubes netted me about 4 mpgs! my 6 spd manual 4.0 4 WD 2011 fronty king cab was averaging 19 mpg when i checked in the summer, VERY pleased!!
 
Messages
15,417
Location
NE,Ohio
Originally Posted by benjy
using all redline lubes netted me about 4 mpgs!
uh what? if that was true redline would have been bought by a car manufacturer and it would be an OEM fluid. Auto manufacturers spend billions searching for a mpg. I am a redline fan but that is physics defying.
 
Messages
6,347
Location
Connecticut
Originally Posted by mobilaltima
My axle code is 26, so it appears I have a Dana 60, 3.55 gears, open differential. I'm not complaining, no limited slip additive to worry about. ls1mike, 75W140 is the spec'd fluid for my truck and most F-150s for quite a few years. I'd like to know as to why they use 75W140, versus most GM 1500, 2500 and 3500s calling for 75W90.
75w140 is supposed to hold up better for towing. I know in my Jeep's owner's manual it says to use 75w140 in the Dana 44 rear axle when towing, and have seen that recommendation in other owner's manuals also. I use Redline in the diffs of all the vehicles I service. The last time I did a diff fluid change on a friend's vehicle I used Redline in previously, the Redline had been in there for 50k miles and looked brand new. I actually wished I had left it in there.
 

mobilaltima

Thread starter
Messages
1,426
Location
Golden Meadow, LA
my mistake I dont have a Dana 60, its a Ford 8.8 rear. Would anyone have the torque specs for the diff cover? I'm getting various answers of 25 ft lbs, 33 ft lbs, and 28-38 ft lbs.
 
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