I have a new 2017 6.2L F250 CCSB with 4.30 gears. About 18 hours after taking delivery I took it back with a noise from the rear of the truck that sounded like a bad bearing. It occurs only in 4th gear with an engine speed of 1100 RPM on either a level road or a very slight incline and a very light touch of the gas pedal just to maintain forward speed. The service manager and his technicians can also consistently reproduce the noise. Ford authorized the replacement of all bearings in the rear differential, but the noise persists.

A computer has been collecting data from the transmission and this has been sent to Ford. So far, Ford can not find the source of the problem. Ford's current leaning is that this noise stems from a "lugging of the drive train." At this point they are saying if the noise cannot be reproduced in a similarly configured F250 they may continue the PD/PSI (Problem Determination/Problem Source Identification).

If the problem does occur in a similarly configured F250, the issue will be closed out as not being a problem. My counter to the lugging theory is that a truck with the 3.73 gears should exhibit this same noise even more often vs. one with 4.30 gears.

I am putting a call out to those who have a truck like mine to try to produce this same noise in your truck and provide the results on this forum thread.

Thanks!

Update: The 4th gear/1100 RPM noise has now been shown to occur in 6.2L F250 trucks with the 3.73 gears as well.
Update #2: I was able to reproduce the noise in 3rd gear at about 1100 RPM, so it is not just a 4th gear occurrence.

 

I have a similar issue except mine doesn't seem to be related to engine speed. I have a thread going here with more details:
https://www.ford-trucks.com/forums/1...placement.html

Our trucks are the same except I have the long bed.

Basically, they have tried the exact same resolution as you, but my problem persists. Here is a quick summary of what I see:

- everything fine up to 80 mph; going on some 85 mph speed limit roads, I noticed a vibration in the rear (yes we have roads with 80-85 speed limits)
- once it starts, the vibration exists from 60+ mph and does not go away if you slow down.
- only way to stop it is to come to complete stop and let it sit for a while
- sounds like what you describe; bad bearing or something. high frequency, low pitch
- unlike yours, it does not depend on engine RPM, gear, or 2hi/4hi operation
- they have replaced pinion and "bearings in the rear end" but have not been able to resolve

Hearing what you have here, I suspect there may have been a manufacturing defect that affects multiple trucks. I wouldn't be surprised if your issue, if left unresolved, would grow to be more evident under different scenarios.

 

Loudpedal,
I appreciate your reply. At this point I can't say I have that dreaded vibration that you and others have described. I do not have any felt vibration that accompanies the noise and the noise occurs at a much lower forward speed, say about 25 MPH.

The technicians notice that the noise does not occur in any other forward gear, just 4th and at 1100 RPM.

 

have them inspect the harmonic dampener.. ( crankshaft pulley parts )

load and rpm issue.
the sound can travel thru crankshaft... transmission and driveshafts.

I hope they find it. and fix it. Best of Luck

 

Gotcha, didn't realize you had noise only. I have read around and saw a couple of reports of rubbing brake pads / sticky calipers. However, unless a braking event is also involved, I doubt that's the issue. Might be a quick check to see if there is any unusual wear to pads or rotors. Good luck, and definitely update the thread if you find anything

 

Update: The dealer got in another 6.2L, but with the 3.73 gears. He was able to reproduce the noise in 4th gear, 1100 RPM, 21 MPH. As it turns out, Ford has said that they have gotten similar reports on the 6.2L F250 trucks. The next test will be to run in Tow/Haul to reprogram for a higher RPM in the gears before upshift to see if the "chugging" (as Ford calls it) disappears. If so, a tweak of the programming may be all that is needed.

 

Has this been reproduced with the F350's 6.2/6R140 combo yet?

 

How do you keep it in 4th at 1100rpm unless you are using the manual mode. Anytime you lug a motor you will get that kind of noise.

Denny

 

Your problem sounds to my like a bad tire not something mechanical. The tire may be in balance but one of them may be becoming distorted at high speed and will not stop shacking until you slow way down.

Denny

 

kry226,
So far this appears to be unique to the 6R100-based TorqShift-G transmission in the F250 with the 6.2L engine.

rvpuller,
You raise a good point. On this truck the upshift happens at a lower RPM when not under significant load. A manual downshift will change the dynamics such that the noise disappears. For some reason, this issue has only been observed in 4th gear. Perhaps that is a clue that Ford need only tweak the shift parameters related to use of 4th gear?

As to the possibility of tire noise, the technicians used diagnostic sensors placed under the truck in an attempt to pinpoint the source of the noise. The rear differential was targeted, but that proved wrong. Also, the noise is much more like that of a bad bearing than tire related noise. Finally, the other F250 w/3.73 gears they road tested exhibited the identical noise.

Now it seems that a "lugging" condition is generating the noise and the noise is transmitted through the driveshaft to the differential. I now wonder if the "lugging" is engine based or transmission based. Could it be that the transmission can "chug" while the engine itself is under no appreciable strain? In my near 45 years of driving experience, any lugging I caused in manual transmissions seemed to start in the engine, which set up a sympathetic back and forth "chugging" within the transmission internals.

 

Does your truck have a hanger bearing for the rear driveshaft? Anyone check that yet?

 

Krewat,
I wish I could answer your question, but the truck only parked in my driveway overnight and I only drove it for a total of 2 hours before taking in for the noise to be diagnosed !!

 

Chuck,
Good thoughts. Your point about noise being transmitted through the length of the drive train to the differential has been born out.

The harmonic dampener has not been brought up yet, perhaps due to the fact that 1100 RPM under light or no load in any other gear has not been problematic. I need to mention that you feel no vibration accompanying the noise. However, that does not necessarily rule out the harmonic dampener since the motor mounts may insulate the driver from any such vibration. I'll bring that up next time I talk with the service manager. He's been great about calling with regular updates.

 

We got our truck back. The rear differential has been ruled out since all bearings in it have been replaced. Ford's roving technician came to the dealership and heard the noise for himself. He reiterated that other reports on this noise, resembling the low rumble of a bad bearing in the rear differential, have come in. At this time there is no resolution. The theory that this stems from a "lugging" condition (only in 4th gear?) does not sound right to me. It sounds more mechanical than that. Given that this is the first year for this transmission (and assuming that that is where the problem actually is), I hope that Ford will release a TSB with a fix soon.

Because of all of the electronics in these trucks I did purchase an extended warranty so I can have some measure of peace of mind in case something craters. Until then we'll enjoy our new truck as I pull our RV trailer this year.

 

I had a slight whine in the rear diff on my '01 (I know, completely different truck, but hear me out)

It happened only when cruising, in OD usually, although it did come up in lower gears at times. And was between keeping speed, and just letting off a slight bit (to decellerate slightly if traffic ahead started to bunch up for example).

I never went to the dealer for it. A few years later, my diff cover was rusting, so I took it off, cleaned it up and put Mobil 1 75w140 in it.

Noise was gone. The diff fluid was the reason for the noise. With all I've put that diff through, it's still fine.

Not saying you should run out and put different fluid in the rear, but if it ever comes time to do so, try something other than the Ford/Motorcraft stuff that meets the specs.