Greetings, This is my first post, so hope I am in right area. My 2017 Larait f150, 3.5 ecoboost, 10 speed had to go into shop on Wednesday. Truck was making a growling sound when in 4A between 15-20 mph. After inspection tech found “glitter in diff fluid.” Tech replaced carrier assembly, both side bearings, and piñon seals. Should I be concerned about this failure? I am not a mechanic, so I am not sure if carrier assemblies “fail!” Best truck ever, but anxious about this repair. (No charges, free loaner car, great service at Kendal Ford Anchorage, AK.)
Thanks for input.

 

I don't know what's up with Ford and their rear diff's lately, but you're not first to have a wasted rear gear on a new truck. At least there's a warranty.

 

Assuming its the front diff, my 16 had to have it replaced as well. What I was told is that on some carriers the pinion is not properly torqued and wobbles, causing ring and pinion wear and eventually trashing the bearings. Sounds like they are still having issues.

Mine is still having vibrations and IWE issues, but with the front diff rebuilt, hoping that it never needs it again.

 

Thanks for replies. It sounds to me like the front differential, but tech replaced rear carrier assembly. I picked up the truck late Friday afternoon and all seemed fine. Drove around today, but after a few miles I am getting the same sounds as before. 4A, electronic diff NOT engaged, and when making right turn on snow/ice covered road, low grumbling sound until speed is above 25mph. I will drive it today and Sunday, but take it back to dealer on Monday. Even my wife can hear the grumbling, especially when turning or climbing a slight hill. Not too confident that the tech will be able to or want to "reproduce the sound" and I will be out of luck.