I have an older dually F350 with a 10.25 rear that I'm installing a later generation 10.5 electronic locking carrier. I think the later unit came from a 2014 F350. Question is normally I would run synthetic 75w-140 but don't want to cause a problem with the locker and I dont have access to the owners manual for the later truck where the carrier came from. What oil would be the proper oil in my case? Any problem with the thicker 75w-140 with the oem elockers? Just for info I do tow heavy for hundreds of miles at a time with this truck. Thank you.
Correct Gear Oil Ford 10.25 Rear with OEM 10.5 E Locker
- Thread starter ChevellRCR
- Start date
75w140 NO MODIFIER
Thank you. I like the heavier oil.
Did you look up the owners manual for a 2014 F350? That would be my first step.
Modifier isn't needed since it's a mechanical locker and not a clutch.
I put in the original post that I dont have access to the 2014 manual. There may be a place to look it up on Ford's website but I don't know. I think Ford went to lighter oils to further assist with emissions but lighter isnt always better for heavy towing. I know the lighter oil will work. Was curious if the heavy oil would give issues?
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Just looked it up here:
https://www.ford.com/support/vehicle/f250/2014/owner-manuals/
Page 296 lists:
Rear axle - F-250/350 (10.50 inch axle)
6.9 pints (3.3L)
Motorcraft SAE 75W-140 Synthetic Rear Axle Lubricant
XY-75W140–QL (U.S.) / WSL-M2C192-A
CXY-75W140-1L (Canada) / WSL-M2C192-A
There are also listings for Dana M80, S110, S130 axles. Either way you'll be fine with 75w140 but you'd probably get slightly higher fuel efficiency with 75w90 probably at the expense of some wear. Our 2014 F150 lists 75w140 for the axle but in later years, with the same axle, they list 75w90.
Thank you for the confirmation. I really appreciate it. I knew at some point they changed everything to 75w90 but I heard it was for emissions reasoning. I dont mind the hit in economy. Would much rather have less wear.
Emissions / fuel-economy, yes.
80w140 synthetic might be easier for you to find. That’s what I’m putting in my son’s new 2012 F350 6.2L.
I’ve got the same rear diff
Started using Redline 75/140 at 35K miles and I’m now at 125K miles and zero issues
75w140 will serve you well
Very
Redline is a great gear oil
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