Vibration after regear
Thread Starter
JK Enthusiast
Joined: Apr 2009
Posts: 112
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From: Albuquerque, NM
Vibration after regear
I just got a shop to regear my JK to 5.38
Everything seems good, except at around 70mph, there's a new vibration from the front end. At lower Speeds, it seems fine. The vibration is there whether there is a load on the engine or I coast.
What could this be? What did they screw up?
One other thing: I did have them install Evo C gussets at the same time too.
Any help would be appreciated. Thanks.
Everything seems good, except at around 70mph, there's a new vibration from the front end. At lower Speeds, it seems fine. The vibration is there whether there is a load on the engine or I coast.
What could this be? What did they screw up?
One other thing: I did have them install Evo C gussets at the same time too.
Any help would be appreciated. Thanks.
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Joined: Apr 2007
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From: Utah
I just got a shop to regear my JK to 5.38
Everything seems good, except at around 70mph, there's a new vibration from the front end. At lower Speeds, it seems fine. The vibration is there whether there is a load on the engine or I coast.
What could this be? What did they screw up?
One other thing: I did have them install Evo C gussets at the same time too.
Any help would be appreciated. Thanks.
Everything seems good, except at around 70mph, there's a new vibration from the front end. At lower Speeds, it seems fine. The vibration is there whether there is a load on the engine or I coast.
What could this be? What did they screw up?
One other thing: I did have them install Evo C gussets at the same time too.
Any help would be appreciated. Thanks.
Thread Starter
JK Enthusiast
Joined: Apr 2009
Posts: 112
Likes: 0
From: Albuquerque, NM
Thanks for all the suggestions.
I'm going to take it back to them. I'll pull my driveshaft as a sort of last resort. I just want to have a nice arsenal of ideas.
So
1. Pinion Nut not tight enough
2. Driveshaft vibrations
Any way an overheated ball joint could cause this?? I can't see how, but that was the other work that was sorta easy to mess up.
Thanks.
I'm going to take it back to them. I'll pull my driveshaft as a sort of last resort. I just want to have a nice arsenal of ideas.
So
1. Pinion Nut not tight enough
2. Driveshaft vibrations
Any way an overheated ball joint could cause this?? I can't see how, but that was the other work that was sorta easy to mess up.
Thanks.
Thread Starter
JK Enthusiast
Joined: Apr 2009
Posts: 112
Likes: 0
From: Albuquerque, NM
I have an update, and need some more advice:
I removed the driveshaft, and the virbation is gone. So the problem is definitely in the driveshaft. The way I see it, it could be 3 different problems:
1. Driveshaft is not balanced. I'm spinning 25% faster (4.1 -> 5.38), and so the out of balance problem is more apparent because the driveshaft is spinning faster.
2. My pinion angle is not perfectly lined up. The u-joint might be vibrating now because its spinning faster. My caster is at about +5 degrees.
3. The guys who did my regear did not mount the driveshaft to the flange on the pinion very carefully, and that is off-center and vibrating.
I have a Tom-woods driveshaft with the non-factory flange. The tom woods mounting flange is a poor design, and doesn't have a very good way of centering the driveshaft to the flange. It relies on the slop in the 4 bolt holes to sort of align it.
Before I take the driveshaft to get balanced, or remount the driveshaft and try to mate the flanges more carefully, does anyone have any suggestions on what the more likely cause is?
Thanks!
I removed the driveshaft, and the virbation is gone. So the problem is definitely in the driveshaft. The way I see it, it could be 3 different problems:
1. Driveshaft is not balanced. I'm spinning 25% faster (4.1 -> 5.38), and so the out of balance problem is more apparent because the driveshaft is spinning faster.
2. My pinion angle is not perfectly lined up. The u-joint might be vibrating now because its spinning faster. My caster is at about +5 degrees.
3. The guys who did my regear did not mount the driveshaft to the flange on the pinion very carefully, and that is off-center and vibrating.
I have a Tom-woods driveshaft with the non-factory flange. The tom woods mounting flange is a poor design, and doesn't have a very good way of centering the driveshaft to the flange. It relies on the slop in the 4 bolt holes to sort of align it.
Before I take the driveshaft to get balanced, or remount the driveshaft and try to mate the flanges more carefully, does anyone have any suggestions on what the more likely cause is?
Thanks!
Thread Starter
JK Enthusiast
Joined: Apr 2009
Posts: 112
Likes: 0
From: Albuquerque, NM
With the driveshaft removed, is there any play in the front pinion?
Can you move it in any directions side to side or up and down with your hands?
Sometimes shops have a difficult time properly setting the crush sleeve. So the front pinion ends up with some slop in it.
Unless you threw or knocked off a weight, I would be surprised if the TW DS is not balanced.
Can you move it in any directions side to side or up and down with your hands?
Sometimes shops have a difficult time properly setting the crush sleeve. So the front pinion ends up with some slop in it.
Unless you threw or knocked off a weight, I would be surprised if the TW DS is not balanced.
JK Enthusiast
Joined: Jan 2008
Posts: 180
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From: Danville, CA
If that was the only change, maybe your driveshaft is just turning faster due to regear and your getting the vibe from that. That happened when I regeared on my 2 door. Only change was the gears. After pulling the front shaft - no vibs anymore. I changed to aftermarket front shaft and it got better - but it moved to 80 mph. On that jeep I just drove under 75 and had no noticeable problems.