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'11-16 General Questions General questions related to 2011-Up Super Duty trucks. If it doesn't fit the other categories, post it here. Gas engine discussion that pertains to all models is allowed. Specific gas engine questions should use the Gas Engines forum.

Thread: '2015 F350 DRW transmission service interval Reply to Thread
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  Topic Review (Newest First)
10-05-2018 04:44 PM
Originally Posted by CajunMick View Post
Also, for the rear ends, those trucks with SRD, or Sterling rears, Ford states fluid good for life, as long not contaminated. For trucks with dual wheel axles, Dana types, Ford states fluid change 30k miles.

That only applies to the DRW if not filled with synthetic gear lube.

2015 Owner's Manual page 446

Axle Maintenance

Change the axle fluid anytime an axle is submerged in water.

Rear axles and power take-off units with synthetic fluid and light-duty trucks equipped with Ford-design axles are lubricated for life; do not check or change fluid unless a leak is suspected, service is required or the assembly has been submerged in water. During long periods of trailer towing with outside temperatures above 70F (21C) and at wide-open throttle for long periods above 45 mph (72 km/h), change non-synthetic rear axle fluid every 3000 miles (4800 kilometers) or three months, whichever comes first. This interval can be waived if the axle is filled with 75W140 synthetic gear fluid meeting Ford specification WSL-M2C192-A, part number F1TZ-19580-B, or equivalent. Add friction modifier XL-3 (EST-M2C118-A) or equivalent for complete refill of Traction-Lok rear axles. See Capacities and Specifications (page 300).

Page 304 of 2015 Owner's manual

Rear axle - F-350 (Dana 8.5 pints (4.0L) M80)

Motorcraft Rear Axle Lubricant 75W-90 Synthetic

10-05-2018 07:36 AM
CajunMick Some of my research on this topic reveals that Ford trannies have dual filtration, and hence, reason why Ford states 150k fluid life.

Also, for the rear ends, those trucks with SRD, or Sterling rears, Ford states fluid good for life, as long not contaminated. For trucks with dual wheel axles, Dana types, Ford states fluid change 30k miles.
09-12-2018 06:58 PM
Phillippeterson The owners manual does indeed say to change at 150,000 miles. However, at 30,000 miles of hard use, I just drained the 8 quarts that come out of the pan and added fresh fluid. There is no access to the torque converter to drain it like I could on older trucks.

My wallet is $50 lighter. But I feel better about it.
09-11-2018 03:55 PM
badbart My understanding is that this Ford 6 speed transmission was originally tested at max load for 250K miles with only OEM recommended maintenance service performed. It was designed to outperform the Allison which GM uses in their comparable trucks. I have contact with Ford techs who tell me they have not seen failures in this transmission that were not low fluid related. It's success is probably due in part to it having a separate cooling system not tied to the engine cooling system. I have over 170K miles on mine and it performs like a new one. I followed the service recommendations and had cooling system flushed, axle lubricants changed, transfer case and transmission fluid exchanged at the 150K mile mark. The tech (a friend of mine) told me the transmission fluid was dirty but not burnt. This is obviously not the transmissions of old.
09-10-2018 09:31 PM
philgrg Ford's Maintenance Schedule Website agrees with the owners manual, 150K. I don't see anything re the transmission at 30K. Here's the link:


I'm with you, I would change it earlier at least by 100K. Fluid is inexpensive in the grand scheme of things.
09-10-2018 04:29 PM
'2015 F350 DRW transmission service interval

From what I have found researching and owners manual, it states replace transmission filter and fluid at 150K. Dealer told me I need to service the transmission at 30K. I have 32K on the truck. It's a daily driver and I tow loaded around 15.5K lbs 5th wheel about 8 times a year.. Most trips include mountain grades. Also tow 6K lbs boat several times a year. What is the "normal" needed transmission service interval for a 350 dually? is the owners manual 150K ok? That sounds extreme and I was thinking unless having issues 1st service on the transmission at 60k.

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