Drive line vibrations fixed!
Thread Starter
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Lead Driver
Joined: Nov 2000
Posts: 6,624
Likes: 342
From: Albuquerque
Drive line vibrations fixed!
In an earlier post I complained of a drive shaft vibration under float conditions after lowering the truck and shortening the shaft.
There was a lot of interest so here are the lessons learned.
Start of problem: truck is lowered 3" in front and now about 3 1/2" in the back. Last upgrade was front spring hangers that drop the rear 1" or 2" depending on the hole used. 2" drop rear hangers were already installed.This moved the rear end slightly forward and required shortening the drive shaft.
That's when the vibration started.
Causes: Too little phase angle. Not! Will ruin the joints but shouldn't vibrate untill the joints wear. 1/2 degree to 3 degrees seems to be the recommended angle. Should be the same on both ends or at least within 1 degree of each other.
Shaft too short: Probable contributor. Too much slip joint exposed allows a wobble.
Shaft not balanced: Probable.
Drive Shaft Industries was kind enought to lengthen and balance the shaft. It wasn't balanced before when it was shortened.
It's very hard to measure angles this small without a dedicated gauge that mount magnetically to the end of each "U" joint cap. I'm looking to buy one. Seems like a good excuse to buy a tool.
This is a rather short single piece drive shaft hanging out of a Gear Venders O.D.
I apologize for the length of post. Hope someone else can benefit from the info.
Thanks for all the input. .......
.........
There was a lot of interest so here are the lessons learned.
Start of problem: truck is lowered 3" in front and now about 3 1/2" in the back. Last upgrade was front spring hangers that drop the rear 1" or 2" depending on the hole used. 2" drop rear hangers were already installed.This moved the rear end slightly forward and required shortening the drive shaft.
That's when the vibration started.
Causes: Too little phase angle. Not! Will ruin the joints but shouldn't vibrate untill the joints wear. 1/2 degree to 3 degrees seems to be the recommended angle. Should be the same on both ends or at least within 1 degree of each other.
Shaft too short: Probable contributor. Too much slip joint exposed allows a wobble.
Shaft not balanced: Probable.
Drive Shaft Industries was kind enought to lengthen and balance the shaft. It wasn't balanced before when it was shortened.
It's very hard to measure angles this small without a dedicated gauge that mount magnetically to the end of each "U" joint cap. I'm looking to buy one. Seems like a good excuse to buy a tool.
This is a rather short single piece drive shaft hanging out of a Gear Venders O.D.
I apologize for the length of post. Hope someone else can benefit from the info.
Thanks for all the input. .......
.........
Posting Guru
Joined: Dec 2002
Posts: 1,297
Likes: 3
From: Billings MT
Drive line vibrations fixed!
Hey Bear,
How was DSI to deal with? I'm kind of partial to U-Joints Inc lately. We use them for some stuff at work and was wondering who else around here is any good. After DTS (DriveTrain Southwest) left, it's been hard to find someone.
Glad to hear that you got the vibrations fixed. I would think that pulling the slip yoke out real far would cause a vibrations(Not enough contact area).
How was DSI to deal with? I'm kind of partial to U-Joints Inc lately. We use them for some stuff at work and was wondering who else around here is any good. After DTS (DriveTrain Southwest) left, it's been hard to find someone.
Glad to hear that you got the vibrations fixed. I would think that pulling the slip yoke out real far would cause a vibrations(Not enough contact area).
Thread Starter
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Lead Driver
Joined: Nov 2000
Posts: 6,624
Likes: 342
From: Albuquerque
Drive line vibrations fixed!
Howdy back at you!
D.T.I. was great. Although if they had got the length right and balanced it the first time it would not have been a problem. They did not charge to redo it. I think the owners name is Larry and he tends to be a little vague but I dealth with Steve Trujillo who went out of his way to help me.
I haven't used any other place since D.T.S. shutdown.
Vibrations can be a real "bear"! ...
...
D.T.I. was great. Although if they had got the length right and balanced it the first time it would not have been a problem. They did not charge to redo it. I think the owners name is Larry and he tends to be a little vague but I dealth with Steve Trujillo who went out of his way to help me.
I haven't used any other place since D.T.S. shutdown.
Vibrations can be a real "bear"! ...
...
