Bad Vibration after Front Driveshaft Install

[ospreyfe55]

I received my 1350 Front Adam's Driveshaft this week and installed it but now I have a serious vibration when in 4hi. I know I wont drive around in 4hi all the time but I would should be able to use 4hi when I need too but since installing the driveshaft I am concerned and cant figure out what to do! I know I had zero vibration issues with the OEM driveshaft at the same speeds I am testing the Adams driveshaft at with zero vibration. The driveshaft feels like its going to exploded under my Jeep at 40-45mph. I called Adam's but was told to call back next week as their driveline specialist was out until Monday. I am going to get some pics and angle measurements of the setup but I known a lot of Jeepers that have gone this route with the same lift/setup I have and have had zero issues. Currently my caster is set at 6 degrees. Did I just get a bad driveshaft? Is there something I should look at? How is the best way to get measurements so I can relay them to Adams?

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[kevman65]

It could be something as simple as not being balanced correctly.

The fastest, cheapest, easiest way to find out is find a drive line shop near you, take the drive shaft off and take it to them to be checked for balance.

 

[ShadowsPapa]

I received my 1350 Front Adam's Driveshaft this week and installed it but now I have a serious vibration when in 4hi. I know I wont drive around in 4hi all the time but I would should be able to use 4hi when I need too but since installing the driveshaft I am concerned and cant figure out what to do! I know I had zero vibration issues with the OEM driveshaft at the same speeds I am testing the Adams driveshaft at with zero vibration. The driveshaft feels like its going to exploded under my Jeep at 40-45mph. I called Adam's but was told to call back next week as their driveline specialist was out until Monday. I am going to get some pics and angle measurements of the setup but I known a lot of Jeepers that have gone this route with the same lift/setup I have and have had zero issues. Currently my caster is set at 6 degrees. Did I just get a bad driveshaft? Is there something I should look at? How is the best way to get measurements so I can relay them to Adams?

is it this shaft? If so -
This end - must be run straight, little to no angle. That's a single cross or single cardan u-joint and those can't be run with any appreciable angle.

I can't believe driveshaft makers put a single joint at the differential end of the shaft. It just boggles the mind. That end should have a CV joint since yo have to run the shaft uphill to the transfer case, and those with lifts often run heavy caster, meaning the pinion is tipped down, while the transfer case is lifted up farther from the pinion of the front axle.
What the heck is up with that?

A properly designed front shaft should have a double joint, or a CV, at the pinion end to take care of the extra caster, or downward tilt of the pinion, and the increased angle to the transfer case due to lifts.
IMO, it's a pissy design.

I've written about this before, even included youtube videos of shafts running at the angles some Jeep people need to run - with a single joint. It shows exactly why it's a crap design and why they vibrate or jerk when turning at angles above about 2 or 3 degrees. 1 degree is best, above that and you start phasing in RPM changes that cause vibrations.

 

[ospreyfe55]

is it this shaft? If so -
This end - must be run straight, little to no angle. That's a single cross or single cardan u-joint and those can't be run with any appreciable angle.

I can't believe driveshaft makers put a single joint at the differential end of the shaft. It just boggles the mind. That end should have a CV joint since yo have to run the shaft uphill to the transfer case, and those with lifts often run heavy caster, meaning the pinion is tipped down, while the transfer case is lifted up farther from the pinion of the front axle.
What the heck is up with that?

A properly designed front shaft should have a double joint, or a CV, at the pinion end to take care of the extra caster, or downward tilt of the pinion, and the increased angle to the transfer case due to lifts.
IMO, it's a pissy design.

I've written about this before, even included youtube videos of shafts running at the angles some Jeep people need to run - with a single joint. It shows exactly why it's a crap design and why they vibrate or jerk when turning at angles above about 2 or 3 degrees. 1 degree is best, above that and you start phasing in RPM changes that cause vibrations.

ShadowsPapa,
Yes sir that is the driveshaft I purchased. I am truly disappointed in the outcome so far. I went with Adam's because that is all everyone recommends and have friends that have the same driveshaft and have no issues. I feel like I went back a few steps because I got my Jeep driving and steering great and now have to play around with caster/pinion settings to get this so work itself out not to mention all the trips to the alignment shop!. I am still going to talk to Adam's specialist on Monday, but I don't have much hope! I may have to just buy a rebuild CV joint for my stock driveshaft and be out the money for this!

Side note, would you happen to know the eye to eye length of the factory UCA's? I am currently running the MetalCloak uppers and Mopar Lift LCA's. So I adjusted my UCAs last night by adding 1/16" or .375 degrees according to MC. So essentially my setting were UCAs @ 19-3/4" to give me 6.5 degree of Caster to now 19-13/16" to give me about 6 degrees of castor. I may have to make a few adjustments to get closer to 5 degrees. I will just going to set my uppers to the OEM spec and go from there.

 

[ShadowsPapa]

ShadowsPapa,
Yes sir that is the driveshaft I purchased. I am truly disappointed in the outcome so far. I went with Adam's because that is all everyone recommends and have friends that have the same driveshaft and have no issues. I feel like I went back a few steps because I got my Jeep driving and steering great and now have to play around with caster/pinion settings to get this so work itself out not to mention all the trips to the alignment shop!. I am still going to talk to Adam's specialist on Monday, but I don't have much hope! I may have to just buy a rebuild CV joint for my stock driveshaft and be out the money for this!

Side note, would you happen to know the eye to eye length of the factory UCA's? I am currently running the MetalCloak uppers and Mopar Lift LCA's. So I adjusted my UCAs last night by adding 1/16" or .375 degrees according to MC. So essentially my setting were UCAs @ 19-3/4" to give me 6.5 degree of Caster to now 19-13/16" to give me about 6 degrees of castor. I may have to make a few adjustments to get closer to 5 degrees. I will just going to set my uppers to the OEM spec and go from there.

Sorry, i don't have the UCA dimensions. If I was outside of my after-surgery limitations, I'd go try to get a decent measurement on them.
I've got a couple of pairs of stock lowers laying around - but so does about everyone else!


I just don't "get" or understand how these driveshaft vendors, and they are all pretty much the same way, want people to change the pinion angle to make that front joint run straight. That means they are saying "we don't care about caster, just adjust your pinion to get rid o vibrations".
why don't they design their shafts so the customer can simply install it, regardless of pinion angle and lift and not have to compromise because the vendors only use a single joint at that end.
They run the CV or double-cardan joint at the other end, so someone had half a brain-thought at one time, but then at the other end where the pinion is likely tilted down slightly, they run a single joint.

 

[Wheelin98TJ]

is it this shaft? If so -
This end - must be run straight, little to no angle. That's a single cross or single cardan u-joint and those can't be run with any appreciable angle.

I can't believe driveshaft makers put a single joint at the differential end of the shaft. It just boggles the mind. That end should have a CV joint since yo have to run the shaft uphill to the transfer case, and those with lifts often run heavy caster, meaning the pinion is tipped down, while the transfer case is lifted up farther from the pinion of the front axle.
What the heck is up with that?

A properly designed front shaft should have a double joint, or a CV, at the pinion end to take care of the extra caster, or downward tilt of the pinion, and the increased angle to the transfer case due to lifts.
IMO, it's a pissy design.

I've written about this before, even included youtube videos of shafts running at the angles some Jeep people need to run - with a single joint. It shows exactly why it's a crap design and why they vibrate or jerk when turning at angles above about 2 or 3 degrees. 1 degree is best, above that and you start phasing in RPM changes that cause vibrations.

Double cardan joints on both ends isn't very commonly needed.

I don't think I have ever seen one on a YJ, TJ, or JK.

 

[ShadowsPapa]

Double cardan joints on both ends isn't very commonly needed.

I don't think I have ever seen one on a YJ, TJ, or JK.

Perhaps if only running slow speeds in 4L but for any speeds in 4H when running the sorts of angles some of them run, there's going to be vibrations.

I'd change what you said to "isn't very commonly used" but at any real speed, it's needed if that pinion is down for caster and there is enough angle upward to the transfer case. I don't get the use of the double joint at the transfer case end - that has less angle. So they seem to feel there's a need there, but where the angle is actually greater, they don't?
That's totally strange. Why do they put the double joint up there, less angle?
It's more needed at the pinion end.

 

[kevman65]

Perhaps if only running slow speeds in 4L but for any speeds in 4H when running the sorts of angles some of them run, there's going to be vibrations.

I'd change what you said to "isn't very commonly used" but at any real speed, it's needed if that pinion is down for caster and there is enough angle upward to the transfer case. I don't get the use of the double joint at the transfer case end - that has less angle. So they seem to feel there's a need there, but where the angle is actually greater, they don't?
That's totally strange. Why do they put the double joint up there, less angle?
It's more needed at the pinion end.

You'll have to ask Dana-Spicer since even their performance drive shafts are made the same way. As are all other after market drive shafts.

You can probably custom order a double cardan on each end, but as stated it is NOT common.

 

[ShadowsPapa]

You'll have to ask Dana-Spicer since even their performance drive shafts are made the same way. As are all other after market drive shafts.

You can probably custom order a double cardan on each end, but as stated it is NOT common.

I'm going to ask them.
It makes zero sense. Even their own videos, all over the internet, youtube and other places, state exactly what I'm saying - you can't run a single cardan joint at such an angle and not have vibrations. it's just not possible.
I know in the case of one REAR driveshaft of the same design - the maker finally said - "oh, you have to change your pinion angle to make that joint straight"
They admitted you needed to adjust the pinion to get close to 0 degrees angle on that joint.
So maybe all of the others running such shafts have changed their pinion angle - or don't run in 4H at any speed.

 

[ospreyfe55]

Well I went out and took some pictures at lunch. I'm not sure if I did anything wrong but I am at a loss here. I'm not sure how much my wallet or my marriage can take of this thing!

 

[Stan H]

Why not put the stock unit back in.

 

[ospreyfe55]

Why not put the stock unit back in.

Because of the lift, its been tore up for a while and start spinning grease out of the cv boot. Trust me if there were other options then that $800 could have been spent else where.

 

[ShadowsPapa]

Well I went out and took some pictures at lunch. I'm not sure if I did anything wrong but I am at a loss here. I'm not sure how much my wallet or my marriage can take of this thing!

You measured 0 degrees at the differential's machined spread boss, so assume all is kosher with the axle housing, that would suggest 0 at the pinion.
Then the 79 i wondered about but you later showed 11, and the way the tool was put in the differential if you called that 90 then minus 79 that would come up with the 11 you got and that if all was measured proper, would indicate a joint angle of 11 degrees.
IF that is not offset at the other end of the shaft by another single joint - refer back to the videos I posted.
The angle of that single joint is trying to speed up and slow down that pinion 2 times for every revolution. Slow speed on slippery surfaces, it's not going to show up much. But if your front tires have grip and you run at speed, then - again, refer back to the videos.

Another fellow here had the same sort of driveshaft for his REAR shaft. It was also a single joint at the pinion or axle end. He ended up having the change the pinion angle to make that joint run at about 1 degree or less. And if I recall, the company he got the shaft from agreed.
(not a pun, not intentional, but I had to laugh after I read that sentence)

The double cardan joint cancels itself out, so it's as if it's not even there and that leaves you with a single joint running at angle, causing that cyclic speeding up and slowing down because of the motion of the cross as it turns.

 

[ShadowsPapa]

Trust me if there were other options then that $800 could have been spent else where.

I can have a custom shaft made for my Javelin setup for racing at that price. A chromoly shaft rated for 3500 horsepower and high RPM - under $700. With a roller bearing slip yoke - about 860. Those are long shafts, precision balanced where any imperfection would cause whipping and destruction.

 

[JTenn]

You measured 0 degrees at the differential's machined spread boss, so assume all is kosher with the axle housing, that would suggest 0 at the pinion.
Then the 79 i wondered about but you later showed 11, and the way the tool was put in the differential if you called that 90 then minus 79 that would come up with the 11 you got and that if all was measured proper, would indicate a joint angle of 11 degrees.
IF that is not offset at the other end of the shaft by another single joint - refer back to the videos I posted.
The angle of that single joint is trying to speed up and slow down that pinion 2 times for every revolution. Slow speed on slippery surfaces, it's not going to show up much. But if your front tires have grip and you run at speed, then - again, refer back to the videos.

Another fellow here had the same sort of driveshaft for his REAR shaft. It was also a single joint at the pinion or axle end. He ended up having the change the pinion angle to make that joint run at about 1 degree or less. And if I recall, the company he got the shaft from agreed.
(not a pun, not intentional, but I had to laugh after I read that sentence)

The double cardan joint cancels itself out, so it's as if it's not even there and that leaves you with a single joint running at angle, causing that cyclic speeding up and slowing down because of the motion of the cross as it turns.

Very interesting topic to me as well. I have recently also installed Adam's drive shafts front and rear and have a rear vibration at 70 mph and above. They are both as you stated, double Carden on the T/C sides and single 1350 u-joints at the axles. Now I don't run at speed in 4hi so the front hasn't shown an issue but it could be vibrating as well. The rear on the other hand definitely has some high speed vibration. Interesting thing is it's WAY worse on deceleration like going down a hill or cancelling the CC. As soon as I hit 68 mph it stops. I believe I can adjust my pinion angle as mentioned above and resolve my issue but beyond that I'll take it to a local shop and have it balanced. Kind of disappointing considering what these things cost but it IS an aftermarket part that is installed on a modified vehicle. I do not believe the drive shaft to be defective but anything is possible.

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