Driveshaft Phasing

[VAMike]

That just goes against science and what has already been proven with driveline geometry. Fords way of saying F off, we're not doing anything about our mistake.

wow, so you're absolutely certain that ford's engineers don't know what they're doing, and you know they're wrong based on...extensive youtube research?

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[TheKracka]

wow, so you're absolutely certain that ford's engineers don't know what they're doing, and you know they're wrong based on...extensive youtube research?

Nothing to do with YouTube, have a background and education in Automotive technology. I refreshed myself with the college books I still have on suspension and drivetrain and it goes against all that is taught. The YouTube video offers a good visual representation. Open minded to perhaps there something that I don't understand but at this point it goes against all that has been taught and still currently taught. So perhaps its a vendor mistake and the Ford rep that sent that message is nothing but a PR rep and not an engineer him/herself.

 

[VAMike]

Nothing to do with YouTube, have a background and education in Automotive technology. I refreshed myself with the college books I still have on suspension and drivetrain and it goes against all that is taught. The YouTube video offers a good visual representation. Open minded to perhaps there something that I don't understand but at this point it goes against all that has been taught and still currently taught. So perhaps its a vendor mistake and the Ford rep that sent that message is nothing but a PR rep and not an engineer him/herself.

Upthread are references to explainations that current driveshafts aren't phased the same way that older ones are. The driveshafts have keyed splines. All of the driveshafts examined thus far are the same. It defies belief that ford 1) carefully built them all wrong to the same specification 2) nobody noticed over the course of two model years 3) the vast majority of them happen to work just fine anyway 4) they went to the trouble of publishing a TSB that describes a method for adding a tiny shim but not mess with phasing to address the small number which do have problems but the whole TSB is a lie and 5) they issued a specific SSM explaining that the phasing isn't wrong because they got so many questions from people familiar with older driveshafts but that is also a lie. IMO it is far more likely that computer modeling and testing indicated that this phasing was better, so that's how they built them. IMO it's so insanely unlikely that ripping the driveshaft apart and forcing it into a different phasing will make anything better that it's not worth even considering.

 

[TheKracka]

Upthread are references to explainations that current driveshafts aren't phased the same way that older ones are. The driveshafts have keyed splines. All of the driveshafts examined thus far are the same. It defies belief that ford 1) carefully built them all wrong to the same specification 2) nobody noticed over the course of two model years 3) the vast majority of them happen to work just fine anyway 4) they went to the trouble of publishing a TSB that describes a method for adding a tiny shim but not mess with phasing to address the small number which do have problems but the whole TSB is a lie and 5) they issued a specific SSM explaining that the phasing isn't wrong because they got so many questions from people familiar with older driveshafts but that is also a lie. IMO it is far more likely that computer modeling and testing indicated that this phasing was better, so that's how they built them. IMO it's so insanely unlikely that ripping the driveshaft apart and forcing it into a different phasing will make anything better that it's not worth even considering.

Understand what you're saying and I would like to give Ford the benefit of a doubt but all too often large corporations make decisions to the benefit of them. In my mind I don't feel that any part of the driveline should be out of phase that articulates with the suspension because once it is compressed angles change and that causes a momentary slow/fast surge at the pinion and is perceived as vibration to the occupants. That's why they're using shims to keep that line from the pinion to the carrier straight as possible to reduce the vibration. It's a solution that will keep most customers happy but my concern is anytime there's a vibration something else is absorbing that shock. It that the pinion, carrier bearing, transmission, or all? Feel like I'm one of the lucky ones and don't have much of a vibration but it's there at times and I hope something else doesn't prematurely fail because of it. We all pay too much for our trucks for things not to be right, perhaps a harmonic damper would be a better solution but then you have redesign of the driveline and additional cost for that kind of solution.

 

[Metalshift]

It would be my guess that Ford engineers had to come up with a compromise . To meet fuel mpgs, modern vehicles have massively overdriven gearing (10spd has has 3 overdrive ratios). The further away you get from 1:1, increasing lugging harmonics at more damaging frequencies occur. This results in drivetrain damage and wear. Ford has sacrificed some low speed/acceleration vibes to prevent high speed cruising wear as this is where most miles occur while in overdriven gears.

This is why you shouldn't lug n chug your vehicle under constant load for any period of time.
I rarely run my ranger under 1900 rpm. After all it is a 4 banger. It will run at 2500 rpm for 300k or more.

I believe a perfectly balanced and phased shaft would have nasty harmonics in 10th gear at 1400-1700 rpm under load. Drivetrain bearing replacement would become a scheduled maintenance item.

 

[TheKracka]

It would be my guess that Ford engineers had to come up with a compromise . To meet fuel mpgs, modern vehicles have massively overdriven gearing (10spd has has 3 overdrive ratios). The further away you get from 1:1, increasing lugging harmonics at more damaging frequencies occur. This results in drivetrain damage and wear. Ford has sacrificed some low speed/acceleration vibes to prevent high speed cruising wear as this is where most miles occur while in overdriven gears.

This is why you shouldn't lug n chug your vehicle under constant load for any period of time.
I rarely run my ranger under 1900 rpm. After all it is a 4 banger. It will run at 2500 rpm for 300k or more.

I believe a perfectly balanced and phased shaft would have nasty harmonics in 10th gear at 1400-1700 rpm under load. Drivetrain bearing replacement would become a scheduled maintenance item.

Certainly follow your logic there and it makes sense. Wasn't even thinking in that direction. Learned me something today.

 

[Frenchy]

It would be my guess that Ford engineers had to come up with a compromise . To meet fuel mpgs, modern vehicles have massively overdriven gearing (10spd has has 3 overdrive ratios). The further away you get from 1:1, increasing lugging harmonics at more damaging frequencies occur. This results in drivetrain damage and wear. Ford has sacrificed some low speed/acceleration vibes to prevent high speed cruising wear as this is where most miles occur while in overdriven gears.

This is why you shouldn't lug n chug your vehicle under constant load for any period of time.
I rarely run my ranger under 1900 rpm. After all it is a 4 banger. It will run at 2500 rpm for 300k or more.

I believe a perfectly balanced and phased shaft would have nasty harmonics in 10th gear at 1400-1700 rpm under load. Drivetrain bearing replacement would become a scheduled maintenance item.

The problem I see with what you are saying is these engines are not being lugged from a 10 speed transmission.can can I see some low RPM's while cruising? Absolutely. I can see as low as 1,500 with certain conditions. If I have a load of sorts like a trailer then I'm going to activate the tow mode as that helps keep a better RPM for power and efficiency. If these engines were being lugged we would know. The joy of an automatic is you have to really mess something up bad to lug them. Does the 2.3 have vibration to it? Absolutely it does but that is normal for a 4 cylinder since a cylinder fires every 180°. If we had more cylinders we could have it a little smoother as it has been proven an engine with more cylinders will run smoother since ther is less time for the next cylinder to fire. With that said I am willing to bet the driveshaft woul provide better harmonics if the phasing was corrected.

 

[SOHK_Alumni]

Ok, enough is enough.

Took my wife's FX4 out of state for a week, pulled the RWD's drive shaft before I left and arranged for it to visit the local Spicer dealer.

$130 plus tax later, the drive shaft is now waiting on me to get home and re-install. The shop machined off the original weld and weights, indexed the two rear u-joints, re-welded and balanced with 1/3 the number of weights.

Looking forward to seeing what, if any changes the reworked drive shaft makes to the overall behavior of the driveline.

For reference, the $130 is less than what it cost for a road force balance and alignment.

 

[Rp930]

Now that is interesting. I don’t have an issue but its a great experiment.

 

[SOHK_Alumni]

Now that is interesting. I don’t havemine has an issue but its a great experiment.

Mine has an UGLY low frequency shake at 45 mph that fades after 50, recurs after 70 as a much higher frequency vibration. Had Ford do a Road Force balance and alignment after I lowered the truck with ZERO effect on the shake/vibration so the effort/$$ on the drive shaft seems reasonable to me.

Very worst case, another $130 will dial back in the OEM 15` out of phase and I'll still be under the cost of the balance/alignment.

Have bought a matching OEM 18" Lariat rim and will get a matching tire. With 5 matching rims/tires I can verify a single wheel/tire combo is not at fault, again, at a much higher cost than the drive shaft re-work.

 

[Frenchy]

Mine has an UGLY low frequency shake at 45 mph that fades after 50, recurs after 70 as a much higher frequency vibration. Had Ford do a Road Force balance and alignment after I lowered the truck with ZERO effect on the shake/vibration so the effort/$$ on the drive shaft seems reasonable to me.

Very worst case, another $130 will dial back in the OEM 15` out of phase and I'll still be under the cost of the balance/alignment.

Have bought a matching OEM 18" Lariat rim and will get a matching tire. With 5 matching rims/tires I can verify a single wheel/tire combo is not at fault, again, at a much higher cost than the drive shaft re-work.

The fact that you lowered your truck it's probably affecting the angles just enough that you needed to correct your drive shaft. That's my guess at least. How much did you lower your truck?

 

[SOHK_Alumni]

The fact that you lowered your truck it's probably affecting the angles just enough that you needed to correct your drive shaft. That's my guess at least. How much did you lower your truck?

Lowered it 2" in front, 4" in the rear. That 45 mph shake was installed at the factory, lowering the truck and changing the driveshaft angles had no effect on the shake at all. Setting the pinion angle at <-1` has been only change I've made that softened the shake in any way.

 

[SOHK_Alumni]

And the verdict is in!

Rather than having a bad shake ar 45 mph, my 2019 is now glass smooth at 45. No high speed results yet, but my expectation is the vibration/shakes are gone for good.

At least for me, money well spent since Ford won't take ownership of the various driveline issues that are widely reported.

 

[Cape Cruiser]

And the verdict is in!

Rather than having a bad shake ar 45 mph, my 2019 is now glass smooth at 45. No high speed results yet, but my expectation is the vibration/shakes are gone for good.

At least for me, money well spent since Ford won't take ownership of the various driveline issues that are widely reported.

Win, did you shorten the shaft because of lowering or just balance it ? Thanks Bret

 

[SOHK_Alumni]

Win, did you shorten the shaft because of lowering or just balance it ? Thanks Bret

Just had it re-phased to align the u-joints and re-balanced.

I moved the axle back about a half inch when I lowered the truck to keep from bottoming out the slip joint so I did not have the overall length altered.

Yea, my eyes see the slightly off center wheel/tire in the wheel well but I chose to let it be.

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