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After 11.7K Kilometers (7250 miles), and since new, the drive line NVH Issue appears to have been resolved in my LWB '15 F150.
Two piece steel drive shaft has been replaced to fix a torque conversion problem at the centre donut. This did not remove the NVH, but did fix the whining screech I would get on quick accels as the rubber innies and outies on the donut rotated past each other, non-lubricating, torque applied. For those of you who do not know, the 6'5" bed length 157" WB trucks have a two piece steel drive shaft.
After 32 days in the shop, differential disassembled and each cog measured, Ford released the crown and pinion gearset for the rear 3.73 rear end and it was installed yesterday. Drove home 80 kms like butter.
Will watch closely over the next few days to see how she settles in, but so far the backlash that was present since new is gone.
Last edited by fringe_remnant; 03-02-2016 at 01:10 AM.
After 11.7K Kilometers (7250 miles), and since new, the drive line NVH Issue appears to have been resolved in my LWB '15 F150.
Two piece steel drive shaft has been replaced to fix a torque conversion problem at the centre donut. This did not remove the NVH, but did fix the whining screech I would get on quick accels as the rubber innies and outies on the donut rotated past each other, non-lubricating, torque applied. For those of you who do not know, the 6'5" bed length 157" WB trucks have a two piece steel drive shaft.
After 32 days in the shop, drive shaft disassembled and each cog measured, Ford released the crown and pinion gearset for the rear 3.73 differential and it was installed yesterday. Drove home 80 kms like butter.
Will watch closely over the next few days to see how she settles in, but so far the backlash that was present since new is gone.
Fantastic news! Being persistent sounds like it paid off. 32 days in the shop, wow!
Now, you're saying the rear differential was causing the vibration? not the drive shaft? Do you know if your drive shaft had run-out prior to the fix?
I think he may have had multiple issues, noise in the center support bearing, driveshaft vibration/runout and excessive backlash in the ring and pinion.
The drive shaft was not the NVH issue. They replaced it as a unit as the centre bearing donut torque converter was faulty.
The backlash at the ring and pinion in the differential was probably due to poor shimming at the factory, causing it to worsen over time. But, nobody will discuss any of this with me. They just replace parts and tell you your vehicle is OK, and ask that you score them well on email feedback requests from Ford.
Noteworthy is that the backlash could be felt all the way forward along the driveshaft into the tranny. The originating dealer's comment was that I should have driven it 'until it breaks'.
32 days is totally unacceptable. I lost business as a result.
Last edited by fringe_remnant; 03-02-2016 at 01:09 AM.
The center support bearing is just that. It supports the center of the 2 piece drive shaft.
Gear clearance is always more pronounced at the pinion/driveshaft due to the gear ratio. The only correct way to measure backlash is at the ring gear or crown gear as you call it. It won't contribute to vibration, but can cause other issues due to what many perceive as slack in the drive train. It will also, eventually cause rear axle gear noise.
One of the problems with NVH is technicians do not understand how to analyze and repair it. So they throw things at it until the customer is satisfied. Years ago I attended a week long class on NVH and it was very thorough and educational, but many of the techs I worked with would not go. They said they didn't need it.
Got it back today (Friday). They neutralized the driveline. Loosened mounts and let them settle naturally and really tightened apparently. They said they tested and it was gone. Absolute bull****. I felt it the first time I creeper into 55 mph on the highway. Going back tomorrow morning to see what they have to say now.
think I'm gonna go next door to Chevy and tell them to make me a deal and be done with this pile of ****. Wanted to love this truck so bad but it appears the F150 just isn't what it used to be.
Got it back today (Friday). They neutralized the driveline. Loosened mounts and let them settle naturally and really tightened apparently. They said they tested and it was gone. Absolute bull****. I felt it the first time I creeper into 55 mph on the highway. Going back tomorrow morning to see what they have to say now.
think I'm gonna go next door to Chevy and tell them to make me a deal and be done with this pile of ****. Wanted to love this truck so bad but it appears the F150 just isn't what it used to be.
Those must be the new instructions from Ford. I received similar treatment earlier this week: "Loosened engine, trans, and exhaust. Neutralized all and retorqued." It's a generic guess, nothing specific to the symptoms of the vehicle.
My service notes said it was 'better' after this procedure, but not fixed. Again, absolute deception. This isn't the issue and they know it. It's not 50% of the problem here, 25% there. There is a 100% direct cause, they just cant find it.
As SKBORDERS said above, this is all an attempt to simply find what satisfies the customer and not what fixes the issue. I have documented evidence that they tried to deceive me this week by calling me and telling me that 'great news!, it's fixed' but then when I go to pick it up they have a drive shaft on order. I asked for an explanation and the service adviser told me they wanted me to drive the truck and see if I was satisfied...and if not, they hedged their bet by ordering a drive shaft.
So new drive shaft next week, but I have serious doubts.
I'll try to Watch this thread my 2.7 with 373 rears is remarkably smooth from the tires all the way to the driveline and all the way up to 100+ miles per hour...
But there is a noticeable amount of backlash and slack in the rear end.
I don't think they are trying to deceive you, they are probably just as frustrated as you are. They just don't know what to do or check and they are doing what ford tells them to do.
If one of the earlier posts is true and the ujoint angles are 3 & 4 degrees, there little doubt in my mind that is part of the problem.
03-01-2016, 05:59 AM
