It’s done. One piece driveshaft!

[Jason B]

Here is a picture of a brand new 2021 F-150 Crew Cab 5 1/2 foot box. Apparently they changed things, one piece driveshaft.

Apparently not on all '21's, as there is a recall on 2 pc shafts on '21 F150's
2021 Ford F-150 Recalled Over Defective Driveshafts (fordauthority.com)

Sponsored

 

[navsnipe]

Apparently not on all '21's, as there is a recall on 2 pc shafts on '21 F150's
2021 Ford F-150 Recalled Over Defective Driveshafts (fordauthority.com)

Interesting! This one has been on the dealership lot for about a month or maybe just a little more, it's an XLT with the 2.7 Ecoboost. Window sticker says is was born on 7/13/21.

I wonder what Ford uses as a deciding factor for one piece or two piece driveshaft? A friend of mine has an F-150 Raptor with a one piece that looks the size of a sewer pipe.

 

[P. A. Schilke]

Interesting! This one has been on the dealership lot for about a month or maybe just a little more, it's an XLT with the 2.7 Ecoboost. Window sticker says is was born on 7/13/21.

I wonder what Ford uses as a deciding factor for one piece or two piece driveshaft? A friend of mine has an F-150 Raptor with a one piece that looks the size of a sewer pipe.

Hi Dave,

I cannot offer why for the current F150, but we at the time back in 2000s had to have a driveline that was above the max vehicle speed of a vehicle by 10%, which in some cases forced into a two piece shaft.

Back Story I told before to a degree.... The Econoline had an NVH problem called Econoline Boom... A loud and annoying booming base drum sound. It was induced by the driveline which in the upper E250/E450 range was mostly Cargo Vans with huge empty cavities, ie no seats... or interior....Work Trucks...

So we decided to introduce composite driveshafts to Truck Engineering to mitigate the driveline contribution to boom. These composite shafts were about 5½" in diameter. They worked very well in the Prototype Econolines. So then we hit production and the NVH was an absolute disaster...
What happened???? Well, this is where prototype parts are "babied" but production was not. What we found was that the production was to to mold and Autoclave the production shafts in these huge autoclaves and then stack the driveshafts in a rack with the ends of the driveshaft supported in the cooling racks but not the center...so each driveshaft sagged into a jump rope which caused terrible vibrations. So several things happened. We stopped making units that needed the single piece drive shaft. The manufacturer was fed the poor quality shafts for breakfast and there was a thrash to make the driveshafts manufacturing process improved to stop the sagging. From then, all was well. So there are still Econolines running around out here with "plastic" driveshafts.

A harror story of Loveland pass Econoline buring to the ground is in another thread on these forums....

Best,
Phil

 

[CHS]

I can tell you my stock shaft was riddled with weights and was not in phase. That’s for sure.

Curious, Before changing the driveshaft out. Did they try re-phasing it to see if it got rid of the vibration? and If it was out of Phase, why not bring it to the dealer (under warranty) show them that it is out of phase (since you can see it visually) and have them fix it first?

 

[Porpoise Hork]

Curious, Before changing the driveshaft out. Did they try re-phasing it to see if it got rid of the vibration? and If it was out of Phase, why not bring it to the dealer (under warranty) show them that it is out of phase (since you can see it visually) and have them fix it first?

If I remember correctly several people on here have gone to their local dealers and were told this is normal and wouldn't touch it. To bring the shaft properly into phase it would require a new splined yoke to be indexed for the OEM back shaft. Not sure how easily it would be to for them to get/make one that would line up. Then the entire shaft would also likely need to be rebalanced.

I may be looking into this option when I have a chance to get over to the local driveshaft specialist to see what they say about it.

 

[VAMike]

If I remember correctly several people on here have gone to their local dealers and were told this is normal and wouldn't touch it. To bring the shaft properly into phase it would require a new splined yoke to be indexed for the OEM back shaft.

To call that "proper" implies that not only is ford engineering so incompetent that they designed the drive shaft wrong, but that they are also too stupid to have noticed, and that when they sent out a notice reassuring people that it really is supposed to be that way they must have been lying. It is clearly phased the way it is for a reason, and until someone fully understands the reason it seems foolish to change it.

 

[Porpoise Hork]

To call that "proper" implies that not only is ford engineering so incompetent that they designed the drive shaft wrong, but that they are also too stupid to have noticed, and that when they sent out a notice reassuring people that it really is supposed to be that way they must have been lying. It is clearly phased the way it is for a reason, and until someone fully understands the reason it seems foolish to change it.

Just because they designed it this way doesn't mean they or the company making the shafts didn't get it wrong. Everyone makes mistakes.

You can look up the importance of driveshaft phasing and see for yourself. Or better yet go talk to a driveline specialist and have them take a look at the shaft. I'd be willing to bet you they will tell you the shaft in the Ranger is not setup correctly. Not only is is out of phase but has numerous counter balance weights on it in an attempt to resolve the vibration issues the shaft has.

Case in point look at the diagram and take a wild guess which one of these is a closer representation to the yoke alignment in the Ranger driveshaft.

 

[VegasRanger]

To call that "proper" implies that not only is ford engineering so incompetent that they designed the drive shaft wrong, but that they are also too stupid to have noticed, and that when they sent out a notice reassuring people that it really is supposed to be that way they must have been lying. It is clearly phased the way it is for a reason, and until someone fully understands the reason it seems foolish to change it.

Yeah because auto manufacturers have never put vehicles into production with improperly designed items...

 

[Rp930]

Some manufacturers, GM in the late 60’s, intentionally made the driveshafts out of phase to help eliminate specific vibrations. It’s not necessarily bad or incorrect. It was a design choice. Apparently not a good one.

 

[quangdog]

I, for one, welcome our new 1 piece driveshaft overlords.

The vibrations in my truck were never super severe, but bugged the crap out of me because I felt it just about every time I pulled away from a stop sign or stop light. I lowered my center bearing which helped a LOT, but there is still a very subtle shimmy/vibration at startup, and a new transient noise/vibration when cruising at highway speeds and lifting off the gas pedal... i.e., cruising at 65 mph on the highway, someone merges in front of me, I lift my foot and hear a very subtle low pitch "moan" sort of sound for 1-2 seconds. I know this is not startup shudder, but I have to assume it's a side-effect of me changing the position of the center carrier bearing.

If I could have a 1 piece fitted for around what you paid that solves all the funky shudders, jitters, noises, etc from the driveline of this truck (with a high confidence that it's the *right* solution) I'd be all over it.

Any idea if/when a bolt-on kit will be available to the general public? Is the Ranger a small enough market that this will pretty much always have to be done onesie-twosie by a driveline shop?

 

[VegasRanger]

I, for one, welcome our new 1 piece driveshaft overlords.

The vibrations in my truck were never super severe, but bugged the crap out of me because I felt it just about every time I pulled away from a stop sign or stop light. I lowered my center bearing which helped a LOT, but there is still a very subtle shimmy/vibration at startup, and a new transient noise/vibration when cruising at highway speeds and lifting off the gas pedal... i.e., cruising at 65 mph on the highway, someone merges in front of me, I lift my foot and hear a very subtle low pitch "moan" sort of sound for 1-2 seconds. I know this is not startup shudder, but I have to assume it's a side-effect of me changing the position of the center carrier bearing.

If I could have a 1 piece fitted for around what you paid that solves all the funky shudders, jitters, noises, etc from the driveline of this truck (with a high confidence that it's the *right* solution) I'd be all over it.

Any idea if/when a bolt-on kit will be available to the general public? Is the Ranger a small enough market that this will pretty much always have to be done onesie-twosie by a driveline shop?

Tom Woods is coming out with one really soon. I would call them up. They are making a list of those interested and will be calling them up when they are available.

 

[VAMike]

Just because they designed it this way doesn't mean they or the company making the shafts didn't get it wrong. Everyone makes mistakes.

You can look up the importance of driveshaft phasing and see for yourself.

You'd better send them that website ASAP: the guys who build drive shafts must not have ever sat through an elementary class on drive shafts so this must all be new to them. ?

FFS, they designed in a spline to force a specific alignment, that's not something that happens by chance.

 

[VAMike]

Yeah because auto manufacturers have never put vehicles into production with improperly designed items...

In the 21st century you don't see elementary errors make it all the way to production. Sure there are unanticipated failures, and assembly problems, and simulations that didn't anticipate everything, but something as basic as "shouldn't the u joints line up"? No way--that's something that engineers have known for at least 100 years and it's something you can notice just looking at the part. In the old days you could assemble the drive shaft wrong so you'll find lots of docs on "my 1980s truck is vibrating" and responses to realign the drive shaft, but manufacturers started designing them so they'd only go together one way like 40 years ago. The tooling to make that part and line it up exactly as specified isn't the kind of thing where someone could just screw it up and nobody would notice or would just say "eh, close enough". Ford would say "we're not paying for those", and the supplier would fix the problem before making a trainload of parts they couldn't sell.

Someone actually posted docs from the drive shaft supplier a while back. I forget the exact language (you can look for it if you're curious) but it was something along the lines of needing to change the phasing because in some cases it was hard to start rotation if they were perfectly in line. Reading between the lines I'd suspect something like "in order to get better efficiency we increased the tolerances so much that in some cases a new driveshaft would lock up and fail catastrophically where an old one would have enough slop to not notice, so we compensated with an alignment that solves the catastrophic failure case but vibrates more at some speeds". Just a guess, could easily be wrong, but I'd want to be well beyond guessing about the reason before deciding what I learned from the internet was better than the guys who get paid to do this. Even a "drive shaft guy" who's a whiz at machining and balancing drive shafts probably isn't running a bunch of simulations or performing destructive testing to learn how this specific part behaves in edge cases on this specific truck. I'd probably go with a solid drive shaft before I'd try to "fix" the OEM part by changing its basic specifications if I was determined to do something (it's a simpler part).

 

[Porpoise Hork]

In the 21st century you don't see elementary errors make it all the way to production.

I'd really like to believe that were true, but sadly it seems that it happens more now than ever.

I'm sure a lot has to do outsourcing across the board as well as with the bean counters sticking their noses in where they don't belong, forcing the engineers to re-design various components to cut costs that ultimately lead to an increased failure rate or recalls.

 

[Big Blue]

One comment and one question.

I'm really glad we have so many driveline experts on this forum that know how to set up a two piece driveshaft better than the company who has been making them for cars and heavy equipment for probably more years than most of us have been alive.

If this drive shaft phasing thing is such a design mistake, how come every truck does not have the problem? And why does it manifest differently on different trucks?

Sorry that was two questions.

Sponsored