One Piece Driveshaft

[NotBudule]

Hi guys, Shawn Wood from Tom Wood’s here. I wanted to chime in on a couple things being discussed here and clear the air a bit.

• From a previous post: “I've been waiting for them to be in stock. Now that they have them they increased the price more than $100. With shipping it's probably $800. Screw'em. My local shop is a lot cheaper and no shipping cost.”. Yes, the price went up a bit more than was originally planned. This was because we decided on a 4” diameter tube instead of a 3.5” diameter and because the cost of the required spacer for the transfer case flange came in a little higher than expected. Frankly, I know we could charge $1,000 for these and people would pay it but the $699 price is fair. We pay the shipping, so that extra $100 you are mad about is awfully presumptuous. Get one locally, or not at all, I honestly don’t care.
• The genesis of the shaft we are offering was not me trying to create a shaft for a vehicle and then making up a problem to sell the shaft. It was multiple people contacting us, sort of desperate, for a solution to the drive shaft issues they are having with their trucks. If there wasn’t an inherent problem with the stock shafts in these trucks, it would be completely off our radar, and we’d never have developed a shaft for it. We create products to fix problems, we don’t create problems to sell products.
• Critical Speed: Whose critical speed calculations are we using? https://pstds.com/critical-speed-chart https://spicerparts.com/calculators/critical-speed-rpm-calculator http://www.wallaceracing.com/driveshaftspeed.php A few months back a trainer from Spicer was here giving us a presentation, among the things he talked about was critical speed. I asked him about how different materials affect critical speed and he did not know the answer. The critical speed calculator on their website does not specify. I do know however that Spicer only uses CREW tubing. We only use DOM tubing. I don’t know if that affects the results of the critical speed or not, but I would assume that it has some effect, as would the material and grade of steel. I think that there are too many variables to say that the critical speed is always X without knowing and calculating all the other factors. But critical speed is a concern, and that’s why we have info about it and a drive shaft RPM calculator on our website. If a guy thinks he needs to drive his truck 100 mph I really don’t want our drive shaft in that truck because I believe it does become unsafe.
• I know, I know, the engineers at Ford all have God-level intellects and never make mistakes. That’s why everything on every Ford vehicle always works perfectly. I’m of course being sarcastic. There are many, many forum threads focused on the issues that are caused by the stock shafts. Despite all the best engineering in the world something isn’t right. I like to think of predicting vibrations as predicting the weather. There’s lots of science that goes into it but sometimes it rains when it’s supposed to be sunny. Now are you going to grab an umbrella or just stand there and get rained on while saying “But it’s supposed to be sunny!”? Sure, the stock shafts in these trucks are supposed to work well, but sometimes they don’t. I’d rather they did and all the people who just spent $40K on a new truck didn’t need to worry about fixing anything. But the stock shafts often don’t work well. So here I am, the guy selling umbrellas.

Bottom line, we brought this shaft to the market at the request of multiple Ford Ranger owners. It was only made available after a long development process, in which we tested the design and made subtle adjustments along the way to ensure the best possible performance. If Ford engineers were infallible we wouldn’t be having this conversation, but we are having this conversation. There’s something just not right with the stock shafts in these trucks. We’re trying to make something better, not perfect, but more right.

I hope I never need you guys but thanks for tackling this issue and being there if I do , 700 bucks seems fair to me sir !

Sponsored

 

[MIBuckeye]

Hi guys, Shawn Wood from Tom Wood’s here. I wanted to chime in on a couple things being discussed here and clear the air a bit.

• From a previous post: “I've been waiting for them to be in stock. Now that they have them they increased the price more than $100. With shipping it's probably $800. Screw'em. My local shop is a lot cheaper and no shipping cost.”. Yes, the price went up a bit more than was originally planned. This was because we decided on a 4” diameter tube instead of a 3.5” diameter and because the cost of the required spacer for the transfer case flange came in a little higher than expected. Frankly, I know we could charge $1,000 for these and people would pay it but the $699 price is fair. We pay the shipping, so that extra $100 you are mad about is awfully presumptuous. Get one locally, or not at all, I honestly don’t care.
• The genesis of the shaft we are offering was not me trying to create a shaft for a vehicle and then making up a problem to sell the shaft. It was multiple people contacting us, sort of desperate, for a solution to the drive shaft issues they are having with their trucks. If there wasn’t an inherent problem with the stock shafts in these trucks, it would be completely off our radar, and we’d never have developed a shaft for it. We create products to fix problems, we don’t create problems to sell products.
• Critical Speed: Whose critical speed calculations are we using? https://pstds.com/critical-speed-chart https://spicerparts.com/calculators/critical-speed-rpm-calculator http://www.wallaceracing.com/driveshaftspeed.php A few months back a trainer from Spicer was here giving us a presentation, among the things he talked about was critical speed. I asked him about how different materials affect critical speed and he did not know the answer. The critical speed calculator on their website does not specify. I do know however that Spicer only uses CREW tubing. We only use DOM tubing. I don’t know if that affects the results of the critical speed or not, but I would assume that it has some effect, as would the material and grade of steel. I think that there are too many variables to say that the critical speed is always X without knowing and calculating all the other factors. But critical speed is a concern, and that’s why we have info about it and a drive shaft RPM calculator on our website. If a guy thinks he needs to drive his truck 100 mph I really don’t want our drive shaft in that truck because I believe it does become unsafe.
• I know, I know, the engineers at Ford all have God-level intellects and never make mistakes. That’s why everything on every Ford vehicle always works perfectly. I’m of course being sarcastic. There are many, many forum threads focused on the issues that are caused by the stock shafts. Despite all the best engineering in the world something isn’t right. I like to think of predicting vibrations as predicting the weather. There’s lots of science that goes into it but sometimes it rains when it’s supposed to be sunny. Now are you going to grab an umbrella or just stand there and get rained on while saying “But it’s supposed to be sunny!”? Sure, the stock shafts in these trucks are supposed to work well, but sometimes they don’t. I’d rather they did and all the people who just spent $40K on a new truck didn’t need to worry about fixing anything. But the stock shafts often don’t work well. So here I am, the guy selling umbrellas.

Bottom line, we brought this shaft to the market at the request of multiple Ford Ranger owners. It was only made available after a long development process, in which we tested the design and made subtle adjustments along the way to ensure the best possible performance. If Ford engineers were infallible we wouldn’t be having this conversation, but we are having this conversation. There’s something just not right with the stock shafts in these trucks. We’re trying to make something better, not perfect, but more right.

Shawn,

Thanks for joining here and providing your EXPERT opinion and product!
Now... you gotta make one for the Tremor... and you'll be shipping one to me too!

 

[Shawn at Tom Wood's]

I've been thinking about how I rhetorically asked the question "Whose critical speed calculations are we using?" I'd like to re-ask that question non-rhetorically. I do not have an engineering degree, I'm just a fairly intelligent person who has been in the drive shaft industry for most of my life. But there are many things I do not know. Spicer seems to be the natural go-to but as I mentioned before Spicer can't explain to me some of the more nuanced details. Also, I've personally brought defects to Spicer's attention which they were resistant to acknowledge. And I've seen them change their own answer on allowable tolerances on some defective parts in order to make the answer fit the mismachined parts. In my experience Spicer is not always right about everything.

@P. A. Schilke I have a few sincere questions for you. Perhaps you can fill in some of the gaps in my own knowledge and gaps in the discussion about these shafts.

1. What is the critical speed of a 4" diameter, 0.083" wall, 1020 steel, DOM tube that is 50" long?
   1. How is this calculated? I'd love to know the math so I don't have to rely on whoever's charts and hope/trust that they actually know what they are talking about.
2. Why is one of the joints out of phase in the stock shafts? Many people discover that and think "So that's why this is vibrating! They messed up and made the shaft out of phase!" as though it is a one-off mistake. I know that the phasing is intentional but don't know for sure why. I think it is done to basically interrupt the frequency of an existing vibration. Can you shed light on this.
3. Lastly, and most importantly, what is the best solution to this problem? If the stock shafts shake and a single piece shaft is a bad idea, what can and should be done?

 

[P. A. Schilke]

I've been thinking about how I rhetorically asked the question "Whose critical speed calculations are we using?" I'd like to re-ask that question non-rhetorically. I do not have an engineering degree, I'm just a fairly intelligent person who has been in the drive shaft industry for most of my life. But there are many things I do not know. Spicer seems to be the natural go-to but as I mentioned before Spicer can't explain to me some of the more nuanced details. Also, I've personally brought defects to Spicer's attention which they were resistant to acknowledge. And I've seen them change their own answer on allowable tolerances on some defective parts in order to make the answer fit the mismachined parts. In my experience Spicer is not always right about everything.

@P. A. Schilke I have a few sincere questions for you. Perhaps you can fill in some of the gaps in my own knowledge and gaps in the discussion about these shafts.

1. What is the critical speed of a 4" diameter, 0.083" wall, 1020 steel, DOM tube that is 50" long?
   1. How is this calculated? I'd love to know the math so I don't have to rely on whoever's charts and hope/trust that they actually know what they are talking about.
2. Why is one of the joints out of phase in the stock shafts? Many people discover that and think "So that's why this is vibrating! They messed up and made the shaft out of phase!" as though it is a one-off mistake. I know that the phasing is intentional but don't know for sure why. I think it is done to basically interrupt the frequency of an existing vibration. Can you shed light on this.
3. Lastly, and most importantly, what is the best solution to this problem? If the stock shafts shake and a single piece shaft is a bad idea, what can and should be done?

Thinly vailed bating.

Not engaging a person trying to sell driveshafts for a living...you are not part of any solution. Look up tables for critical speed....Not in this day and age of CAE analysis...I refer you to Altair Engineering...A cutting edge inventor of much of the analysis software for non linerar flexure mode analysis... And oh yes..I consulted for Altair in retirement.

Hey Chris....hope your purchase includes a driveshaft loop not for your benefit but for the poor folks around you when and if your EXPERT driveshaft breaks, which I hope is never occurs.

Best,
Phil

 

[Shawn at Tom Wood's]

Thinly vailed bating.

Not engaging a person trying to sell driveshafts for a living...you are not part of any solution. Look up tables for critical speed....Not in this day and age of CAE analysis...I refer you to Altair Engineering...A cutting edge inventor of much of the analysis software for non linerar flexure mode analysis... And oh yes..I consulted for Altair in retirement.

Hey Chris....hope your purchase includes a driveshaft loop not for your benefit but for the poor folks around you when and if your EXPERT driveshaft breaks, which I hope is never occurs.

Best,
Phil

Phil. I was actually being sincere in my request for more information. I have looked up multiple critical speed tables. The results vary wildly. That is why I was asking for clarification. What do I think I'm baiting you to do? Objectively answer a couple engineering questions so people better understand things and make well informed decisions? As mentioned before, the only reason we make these shafts is because many people requested them. I frankly always have trepidation when launching a product for a problematic vehicle. If I think there's going to be problems, it's in my best interest to stay uninvolved. If you are going to say that these trucks are going to exceed the critical speed limitations of a one piece shaft can you please at least quantify that for us? What is the limit? Just saying it's a bad idea but not clearly explaining why is not helpful to anyone. Yes, I do sell driveshafts for a living. But honestly we do so well with other driveshafts that the sales of these Ranger driveshafts are inconsequential. I have no greed attached to this shaft. We hardly do any shafts for Fords. I choose not to market them much because Ford shafts are often, honestly a pain in the butt. I feel like your ego is hurt because people dare acknowledge a problem created by the venerable Ford engineers. If you feel the one piece shafts are truly unsafe, please help me/us understand why. I'd rather pull them from our website and throw away the parts than sell something that is potentially unsafe. And if the one peice shaft is unsafe, what can people do instead? I've talked to one guy who took his truck back to the dealer because he was so unhappy with it, bought a Toyota instead. The people on this forum are here seeking help with their problems, not here to squabble about who's right. My goal is to help them. Yours should be too.

 

[SigOris]

Habit 5: Seek First to Understand, Then to Be Understood

https://www.franklincovey.com/habit-5/

 

[TJC]

I have the shudder as well and at times it drives me crazy! I have a Ranger XLT Sport with 4x4 and locking 3.73 differential. It came with Bridgestone Dueler A/T tires 265/55-17. They are 30.1" tall.

Based on the calculator on the Tom Wood website (and simple math)

Here are the driveshaft RPMs at speeds from 55mph to 95 mph

95 mph - 3957 - 98.8% of limit
90 mph - 3749 - 93.7% of limit
85 mph - 3541 - 88.5% of limit
80 mph - 3332 - 88.3% of limit
75 mph - 3124 - 78.1% of limit
70 mph - 2916 - 72.9% of limit
65 mph - 2707 - 67.6% of limit
60 mph - 2500 - 62.5% of limit
55 mph - 2250 - 56.2% of limit

I may speed at times, but I don't intend to push 100mph or even 90 mph in my Ranger. I did that once (90mph) and experienced severe shudder until I dropped it down to 75mph. It wasn't tires out of balance either (I checked). I can't prove it but I think it was driveshaft related. I have not been close to that speed since.

I typically run 5 over the limit at most, and around here in NC that is 75 mph. Almost 900 driveshaft RPMs below the 4000 limit.

I have no idea how fast my 2020 Ranger will go, but I do know how fast I am willing to go, and it is not 95mph in my Ranger.

I have no idea if Tom Woods tested the driveshaft at 4000 RPMs, or how they came up with the number, but if it is accurate, I'd be comfortable installing it on my Ranger.

My 2005 Ranger has a straight shaft and it has served me well for 160K at speeds of 75 mph on the interstate. U joints are still tight. Ford didn't install a driveshaft safety loop on it from the factory. Maybe I should now as it is 17 years old. The transfer case, drive shaft, and diffs are the only things that I did not replace when I rebuilt it.

Tony

 

[navsnipe]

What is very interesting is Ford has used both one and two piece driveshafts on F-150's over the years. They have also been affected by the driveline shudder. I asked a relative of mine, who has worked for Ford for a considerable time, about the Ranger and F-150 driveshaft applications. He spoke with people in this area of technical knowledge and the response was disappointing. I can't even get "an off the record" answer other than they were engineered for a specific application.

The best Ford will do on the Ranger is measure the driveline angles, check NVH, and inspect the driveline integrity and if they are in spec they tell you that's the best you'll get. I went through the TSB 20-2277 saga and to get a tech do do it right was a challenge.

I would love to get a one piece driveshaft from Tom Woods for my Ranger, because it has solved the shudder problem for others, but I am waiting to see all the information. Hopefully someone will provide that and allow us to make an educated decision.

 

[Jason B]

I refuse to believe that the answer is if Ford designed it that way, it's good enough, or if they can't fix it, you just have to live with it and accept it as the best they can or will do. No matter how many years someone worked there for Ford.

 

[MountainGoat]

I have the shudder as well and at times it drives me crazy! I have a Ranger XLT Sport with 4x4 and locking 3.73 differential. It came with Bridgestone Dueler A/T tires 265/55-17. They are 30.1" tall.

Based on the calculator on the Tom Wood website (and simple math)

Here are the driveshaft RPMs at speeds from 55mph to 95 mph

95 mph - 3957 - 98.8% of limit
90 mph - 3749 - 93.7% of limit
85 mph - 3541 - 88.5% of limit
80 mph - 3332 - 88.3% of limit
75 mph - 3124 - 78.1% of limit
70 mph - 2916 - 72.9% of limit
65 mph - 2707 - 67.6% of limit
60 mph - 2500 - 62.5% of limit
55 mph - 2250 - 56.2% of limit

I may speed at times, but I don't intend to push 100mph or even 90 mph in my Ranger. I did that once (90mph) and experienced severe shudder until I dropped it down to 75mph. It wasn't tires out of balance either (I checked). I can't prove it but I think it was driveshaft related. I have not been close to that speed since.

I typically run 5 over the limit at most, and around here in NC that is 75 mph. Almost 900 driveshaft RPMs below the 4000 limit.

I have no idea how fast my 2020 Ranger will go, but I do know how fast I am willing to go, and it is not 95mph in my Ranger.

I have no idea if Tom Woods tested the driveshaft at 4000 RPMs, or how they came up with the number, but if it is accurate, I'd be comfortable installing it on my Ranger.

My 2005 Ranger has a straight shaft and it has served me well for 160K at speeds of 75 mph on the interstate. U joints are still tight. Ford didn't install a driveshaft safety loop on it from the factory. Maybe I should now as it is 17 years old. The transfer case, drive shaft, and diffs are the only things that I did not replace when I rebuilt it.

Tony

You would be surprised coming from a very slow vehicle to a quick one, go to pass someone doing 60 in a 70 zone and before you know it...to say nothing of tuned trucks. 100mph is the new 75.

Maybe at some point someone will design a better driveshaft support for the stock driveshaft that can lesson the bumping since that was the part I had to have replaced at the dealer when it started to squeak and its the part the driveshaft is bouncing in Kimball's vid. Maybe replace the material with something stiffer.

https://www.ranger5g.com/forum/goto/post?id=470049

https://www.ranger5g.com/forum/attachments/18f810267d3d850b42086bbffac3a5a8-png.145766/

 

[navsnipe]

I refuse to believe that the answer is if Ford designed it that way, it's good enough, or if they can't fix it, you just have to live with it and accept it as the best they can or will do. No matter how many years someone worked there for Ford.

I am agreement with you. My relative is not in a technical group, but was at one time, and reached out to people in the engineering areas. I think there are solutions but Ford has prioritized their efforts in electric vehicles and dealing with quality control issues on their cash cows that our Rangers are minor consequences, in my opinion based upon what I have heard.

 

[Big Blue]

I'm going to prefice this post with a disclaimer. I have no dog or any other animal in this fight. My '19 FX4 SuperCab is completely smooth. If there is any studder/shudder/vibration it is so minor as to be unnoticable. As a retired mechanical designer/engineer, I have found it interesting to follow this and the other threads on the same subject.

The biggest question I have is if the Ford design is so bad, why do the vast majority not have the shudder? Before you go off on me, hear me out. On here it seems like a huge issue and I am sure it is for the people who have it. But, what about all the people who don't? Remember the squeaky wheel gets all the attention.

I'm happy for those of you that the one piece driveshaft has helped your shudder, but I still waiting for the one that it doesn’t. I can’t help but think it is treating a symptom of some other issue. If the driveshaft design was truely the cause of the problem, every truck would have it and Ford would have fixed it.

My years of working as a plant engineer taught me that sometimes finding the real ROOT cause if an problem takes a lot of digging and analysis. Sometimes you never find it, and the best you can do is bandiad the symptoms and hope it doesn't pop up somewhere else.

Again, if the one piece shaft works for you, great. Just remember, sometimes the bandaid come with other unseen consiqences. If you can live with them great. I still beleive we haven't found the true cause of this issue and would not be placing blame on anyone.

 

[SigOris]

I'm going to prefice this post with a disclaimer. I have no dog or any other animal in this fight. My '19 FX4 SuperCab is completely smooth. If there is any studder/shudder/vibration it is so minor as to be unnoticable. As a retired mechanical designer/engineer, I have found it interesting to follow this and the other threads on the same subject.

The biggest question I have is if the Ford design is so bad, why do the vast majority not have the shudder? Before you go off on me, hear me out. On here it seems like a huge issue and I am sure it is for the people who have it. But, what about all the people who don't? Remember the squeaky wheel gets all the attention.

I'm happy for those of you that the one piece driveshaft has helped your shudder, but I still waiting for the one that it doesn’t. I can’t help but think it is treating a symptom of some other issue. If the driveshaft design was truely the cause of the problem, every truck would have it and Ford would have fixed it.

My years of working as a plant engineer taught me that sometimes finding the real ROOT cause if an problem takes a lot of digging and analysis. Sometimes you never find it, and the best you can do is bandiad the symptoms and hope it doesn't pop up somewhere else.

Again, if the one piece shaft works for you, great. Just remember, sometimes the bandaid come with other unseen consiqences. If you can live with them great. I still beleive we haven't found the true cause of this issue and would not be placing blame on anyone.

Like fixing an air leak

patch one leak and now the pressure has increased which causes another leak to show

btw, EE here who’s worked USN surface combatants for over 40 years and can attest to your plant manager experiences

i wish conversation didn’t go the way it did as I was learning things out of my wheel house

 

[navsnipe]

I'm going to prefice this post with a disclaimer. I have no dog or any other animal in this fight. My '19 FX4 SuperCab is completely smooth. If there is any studder/shudder/vibration it is so minor as to be unnoticable. As a retired mechanical designer/engineer, I have found it interesting to follow this and the other threads on the same subject.

The biggest question I have is if the Ford design is so bad, why do the vast majority not have the shudder? Before you go off on me, hear me out. On here it seems like a huge issue and I am sure it is for the people who have it. But, what about all the people who don't? Remember the squeaky wheel gets all the attention.

I'm happy for those of you that the one piece driveshaft has helped your shudder, but I still waiting for the one that it doesn’t. I can’t help but think it is treating a symptom of some other issue. If the driveshaft design was truely the cause of the problem, every truck would have it and Ford would have fixed it.

My years of working as a plant engineer taught me that sometimes finding the real ROOT cause if an problem takes a lot of digging and analysis. Sometimes you never find it, and the best you can do is bandiad the symptoms and hope it doesn't pop up somewhere else.

Again, if the one piece shaft works for you, great. Just remember, sometimes the bandaid come with other unseen consiqences. If you can live with them great. I still beleive we haven't found the true cause of this issue and would not be placing blame on anyone.

What I find interesting about the driveline shudder is a number of things.

1. There is a TSB that is specific to the take-off driveline shudder. I has been confirmed that if a TSB exists that there is a number of cases that the engineering group is involved in trying to resolve it.

2. I have dealt with two dealerships that have compared my truck to other new Rangers in inventory they and tell me they exhibit the same characteristic. Their words.

3. The technical service manager my relative reached out to to has a Ranger and it has a shudder. This manager was the one who got an area Field Service Engineer to get involved with my truck.

4. The FSE worked with the driveline specialist at the local dealership. It was relayed to me that my truck was within spec and was pretty mild compared to others they had dealt with. There was nothing more they could do.

5. I spoke with a friend who works for a Ford subcontractor that produces driveline components. He works in the engineering and NVH areas. His opinion was the material the center bearing support was made of was too soft. He said this is a compromise to deal with vibration and noise transmitted to the chassis. A single piece driveshaft removes this component. He stated the critical speed engineering of a one piece shaft should be above the max speed of the vehicle and for a driveshaft as long as the Rangers may be not practical for cost and clearance reasons. We did not get into the calculations for it.

6. It took four attempts to get TSB 20-2277 implemented correctly. I did the forth correction as neither of the two dealerships that did it could do it right. The FSE confirmed I did do it correctly. The major issue on the dealerships third attempt was the leaf spring center pin was not even in the hole on the left leaf spring perch. I took it for an oil change and alignment at a later date. When they told me the thrust angle on my truck was 0.45°, the max tolerance was 0.50° I asked if the leaf spring could have slipped on the perch. The service manager at the dealership told me this was impossible. I found out it was very possible they way they installed the shims.

I could continue on but these identify what I have dealt with and I'm sure many others have a similar experience. The thread on this issue is very long.

I am jealous that your truck has no shudder. I would love for Ford look at it and determine why that is. I guess I am not squeaky enough the Ford will put more time into my truck. I will not go to a single piece driveshaft until I am convinced it is the right solution. It would also put my drivetrain warranty in jeopardy installing one.

 

[navsnipe]

I'm happy for those of you that the one piece driveshaft has helped your shudder, but I still waiting for the one that it doesn’t. I can’t help but think it is treating a symptom of some other issue. If the driveshaft design was truely the cause of the problem, every truck would have it and Ford would have fixed it.

I singled out this quote specifically as to when I spoke with Shawn Woods on the phone a few months ago he did indicate there was at least one case where the single piece driveshaft did not fix the issue. We did not go into specifics why. He had the customer return the shaft and issued a refund.

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