Is anybody else having a problem with a whine coming from the differential at 50mph (80kph) and what repairs are being done to correct?

My F150 started having a whine at 50mph after I got about 8000 miles on it. Its only noticeable at 50-55mph. If you take your foot off the accelerator the whine stops. No noticeable whine above or below that speed.

My dealer just changed out the pinion gear and bearing and now it whines even louder. It starts whining at 50mph, but now when you take your foot off the accelerator the whine gets louder and keeps whining all the way down to 35mph while coasting(no load on the differential)

Any help or input if you had this problem and got it corrected is appreciated

 

I had this happen to my '13 F150, and they ended up replacing the ring and pinion. The noise came back, and the truck spent a full month in the shop while they tried to figure out why it came back. Turns out the tech got the pinion depth a little off.

My '15 is developing a similar whine; only on the throttle, and at the same 50-55 MPH speed range. I'm gonna let this one go for now. If it gets worse it'll be going in, most likely for a ring and pinion. That whine is caused by the gears improperly wearing in, and the only fix is to replace them. Not a cheap thing to do, the job takes almost a full day.

 

Thanks for the feedback Tom. Thats what I'm thinkin as well since they didnt replace the ring and I think they got the pinion clearance wrong , causing more noise now

 

cannot just replace the pinion. they have to be replaced in sets as they wear together.

 

Finally they got it repaired after another week at the dealer. They replaced the ring and pinion a second time. Its quiet now, but we will see in another 20000 Km.

 

FWIW, getting the ring and pinion aligned properly is unforgiving of even minor errors. Not giving them a pass, but it's not the first time I've heard of this kind of issue.

 

A friend of mine has had his new Truck in the shop waiting for a new diff. Is this a common problem ? Why else would it take a month for parts?

 

Possibly because it's not a common problem? Of course, it does take a smidgen of skill to align the gears in a differential.

 

I had a loud whine a 55mph and 70mph. My mechanic put it on the rack and we jacked up the differential. With a stethoscope, We listened to the bearings and all sounds were normal. He suggested we rotate the tires (Mastercraft HSX Courser 265/60 R-18 21,000 miles on the tires). The result was dramatic, only the faintest of sounds and pavement made some difference also on the test drive.

 

Well after 3 attempts to fix the rear end whine Ford finally relented and agreed to replace the entire axel assembly. So the dealer gives me a new 2017 F150 Crew Cab while they have my tuck for 2 weeks to repair. The new truck has 300km on it and 3.31 gears. IT whines as loud or louder than my truck at 82-85 KPH . Again only under load and very evident if towing a 2000lb trailer.
After 2 weeks I get my truck back with new axel housing, gears and bearings.
It ran a lot quieter at the start with no load, BUT after about 2000km on it I notice that it is starting to have a faint whine when I am towing my 2000lb boat trailer up a hill at that magic 82-83 kph.
I am begining to believe that Ford has a design flaw in these axel assemblies which results in a resonance at that gear rpm. You can only engineer so much cost outta these assemblies before you run into issues like this.
Guess I will just have to turn the radio up and make sure that I drive under 80 or over 85 kpH to avoid hearing the whine. Warranty is good for 5 years so I guess I'm good for a while- then it will be off to a TOYOTA after 50 years of F150's

 

Which rear axle is it? The 8.8 or the 9.75?

 

I believe its a 9.75 - 3.31 locker