One Piece Driveshaft

[Justin says...]

Just got to work and did a nice, normal drive all the way here , everything seems good , great even, and it's too early to tell for sure but my clunk coming up on stoplights seems to be missing , and just to see, I actually put it in "D" for a while, which I never do because of the low RPMs and the "lug" when it drops below 1500 , and it feels WAY better in that situation, but I still hate low RPMs(in this truck ) so that's a non-issue for me ...
Still going to take the cord back out and replace with something that flexes a little and retest , it has 0 flex right now , which concerns me a little since it had so much before ,
Tailgate was unaffected and still lowers properly with no delay or hesitation...

Good to hear. Just a quick question: You said you never drive in D, so I'm assuming that means you always use sport mode? Just curious. Thanks

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[Fitzmotor]

Very interesting, I expected it to go the other way, I figured Ford made the center support bearing soft to help isolate the vibration (which they may have) but who knows, the proper fix may be to keep the driveshaft spinning properly instead of like a jump rope.

I am very much following this one, I have fiddled with the shaft angles in all combinations, some joints at zero, some with the working angle, equal working angles at all joints (this should have worked but it didn't) I even turned over the center support bearing and put spacers and long bolts to set it's height for angle changes, my truck is pretty good but still has a rumble under certain conditions.

At Honda Racing we had many levels of designers, some should only be designing Civic door handles, others had designed stuff like the VTEC.

One of the best designers once told me, "the difference between a good and bad designer is how many design revisions it takes to fix a design problem" usually it's not perfect off the drawing board.

Of course us knot heads in the engine shop who had to deal with some of the stupidest designs ever, described it a different way, "some designers couldn't pour piss out of a boot if the instructions were on the heel"

 

[Dr3wDrop]

I am just waiting for someone to 3D print a shim now for the driveshaft joint and boom, no more issues.

 

[NotBudule]

Good to hear. Just a quick question: You said you never drive in D, so I'm assuming that means you always use sport mode? Just curious. Thanks

I 6000 miles and probably less than 100 in D , my commute has places where it drops below 1500 rpms and the "lug" (can't lug an automatic) was unbearable to me , i always enable tow mode at start up and shift into sport when I want to , which is most the time , I tried D again just to see how it acts now, it still drops rpms of course , but I really don't feel it nearly as bad , still , truck still hates anything below 1500 , as do I...

 

[NotBudule]

I am just waiting for someone to 3D print a shim now for the driveshaft joint and boom, no more issues.

I was thinking that very thing, it has "teeth " like a gear all the way around it , may be able to match the pattern, I'm stopping at Home depot after work and lookey look , I'm worried I may have it "too solid " and maybe a happy medium would be better...

 

[MountainGoat]

I am just waiting for someone to 3D print a shim now for the driveshaft joint and boom, no more issues.

The shim would be the solution for me. The single-piece critical speed is to low for me to be comfortable with when I've had the cruise control at 85 on I70.

 

[navsnipe]

I was thinking that very thing, it has "teeth " like a gear all the way around it , may be able to match the pattern, I'm stopping at Home depot after work and lookey look , I'm worried I may have it "too solid " and maybe a happy medium would be better...

You may have better luck at an auto parts store. Maybe some rubber or urethane tubing. I was seeing what I had from my junk project materials that would fit. I'll find out what tubing I had that fit and post the dimensions and material. This was only on my shop floor as I am happy as a pig in shit with my Tom Woods driveshaft and have no desire to remove it for experiments.

Maybe some small cogged drive belt may match the geared pattern of the center bearing support. Drive belt would be non-compressible though.

 

[NotBudule]

I am confused though , where did the vibration go ? Mine at the moment is as firm as it could possibly be ,the exact opposite of the way it was designed , I should have made it worse , and I'm testing an empty truck , loaded or towing may be completely different... tis odd , but I like my truck better today than I did yesterday, so far, so good...

 

[Dr3wDrop]

I am confused though , where did the vibration go ? Mine at the moment is as firm as it could possibly be ,the exact opposite of the way it was designed , I should have made it worse , and I'm testing an empty truck , loaded or towing may be completely different... tis odd , but I like my truck better today than I did yesterday, so far, so good...

Is the vibration the slop in the joint? Removing the slop would remove the vibration, possibly.

 

[Muddy Fenders]

Tailgate was unaffected and still lowers properly with no delay or hesitation...

I have heard that putting spray foam inside the tailgate also helps with the HPFP noise.

 

[Jason B]

In response to a couple recent posts:

About the low cost of the stock shafts. I can buy a new stock shaft (retail) for about the same price as I can buy the parts (wholesale) to build a one-piece shaft. The stock two-piece obviously uses more parts and more parts should mean more expense. But it doesn't, so to me that says something about the initial cost and correlated quality of the parts being used in the stock shafts. I'm not saying the price is conclusive proof that the stock shafts are built cheaply but there is certainly some substance to this idea

It's the economy of scale. You buy parts to build shafts as needed, Spicer/Ford buy parts in the hundreds of thousands to meet production.

I am just waiting for someone to 3D print a shim now for the driveshaft joint and boom, no more issues.

That's an idea I may tackle soon. Maybe in something rigid like PLA or PETG, and something flexible like TPU. Changing the infill density of the TPU will affect its rigidity. I'll just need to find time to crawl under there for measurements.

 

[Shawn at Tom Wood's]

It's the economy of scale. You buy parts to build shafts as needed, Spicer/Ford buy parts in the hundreds of thousands to meet production.

I of course know how economy of scale works. But we aren't exactly buying parts 10 at a time either. Last year we built around 15,000 drive shafts and spent $3,626,349 on drive shaft parts. That means we are purchasing pretty dang close to $10K a day, 365 days a year. Believe it or not we sometimes have more of certain parts in stock than Dana or NEAPCO. We are high volume purchasers but for sure not as high volume as Dana or Ford. But there's a limit to economy of scale too. It doesn't necessarily cost less per unit to make 10,000 of something than it does to make 1,000 of something.

Again, not saying that the low price of the stock shaft is conclusive of low quality but it is something worth noting that they can retail a more part intensive shaft, at a profit, for such a low price. Cheap parts? Cheap labor? Maybe all it says is that Dana is grossly overcharging us for parts! ?‍

 

[Muddy Fenders]

whats the purpose of the shim idea on the 3D printer? allow the original rubber built to move, but limit its overall movement?

 

[Jason B]

I of course know how economy of scale works. But we aren't exactly buying parts 10 at a time either. Last year we built around 15,000 drive shafts and spent $3,626,349 on drive shaft parts. That means we are purchasing pretty dang close to $10K a day, 365 days a year. Believe it or not we sometimes have more of certain parts in stock than Dana or NEAPCO. We are high volume purchasers but for sure not as high volume as Dana or Ford. But there's a limit to economy of scale too. It doesn't necessarily cost less per unit to make 10,000 of something than it does to make 1,000 of something.

Again, not saying that the low price of the stock shaft is conclusive of low quality but it is something worth noting that they can retail a more part intensive shaft, at a profit, for such a low price. Cheap parts? Cheap labor? Maybe all it says is that Dana is grossly overcharging us for parts! ?‍

Well that is good to know. That fact raises my confidence in your work and company.

whats the purpose of the shim idea on the 3D printer? allow the original rubber built to move, but limit its overall movement?

Instead of injecting poly urethane into the bearing support, we can maybe 3D print inserts that can be pushed into the voids to limit movement. If it doesn't work, the inserts could be removed, whereas poly urethane would be a more permanent mod.

 

[TJC]

"I like my truck better today than I did yesterday, so far, so good..."

I feel the same. I now enjoy driving the truck.

I always find it interesting how issues like this play out.

For instance, you build a house to 99.95% complete, but leave off the door knobs, faucets, and light switches. Makes the place completely unlivable...

There is a lesson in this somewhere....

And FWIW, I am staying with the one piece driveshaft. My truck has never driven so smooth. And it is one less point of failure over the long haul.

- T

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