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Oscillating Vibration


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d.markowski

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Adding to this...and correct me @JMT if I'm wrong, that appears to be a Dana 44, and the 2nd horizontal rib on the housing may line up with the pinion...if so...it's pretty high. Maybe more than you think. A jar of water and a marker can tell you alot if you can't get a gauge.

Here's what you need to do. It's Christmas Eve ...walk in the house, tell them Santa ain't coming til his sleigh doesn't have vibes, and get everybody out in the garage to help, Let us know how that works.

Also, and this is really important, it's a good time to tell the kids and grandkids the truth about Santa Clause....he was shot down in a helicopter over the Soviet Union.
Lmao!
 

Goatman

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Pinion angle looks better in second pic (from sitting on my sofa with the dog snoring on my lap while I drink my 'adult' beverage) but I think another degree or two would be better to deal with the torque movement of the axle.🍻
 
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d.markowski

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Soooo. Bought an angle finder and got my driveshaft at 19 degrees and diff at 17 degrees. Still got the vibe. I’m gonna try taking the rear driveshaft off and using front only. Thought I’d also note that the vibration is gone when I take the jeep out of gear and coast. I’ll reiterate that the vibration only happens over 45 mph.
 
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d.markowski

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Update everyone! Sooo we are getting somewhere. I removed the rear driveshaft and put the front back on. Low and behold. The vibration is gone! I have deduced this vibration to 1 of 3 things.

1. Bent output shaft in transfer case. I have ordered a new SYE kit. I think this is the culprit because the problem seems to have started 5 years ago when I upgraded to and SYE and double cardan driveshaft.

2. Out of balance Tom woods driveshaft. Less likely because I had it sized and rebalanced twice. If the new SYE doesn’t help, I will take it to another place to have it rebalanced. UJoints are all in good shape.

3. Pinion angle. Least likely as I have messed with this. Had it +1 degree from driveshaft angle. Had it 0 degrees from driveshaft angle. Had it -1 degree (pinion angle slightly below angle of driveshaft).

Hopefully the new SYE kit fixes the problem. The one I currently have is a terraflex one and I’ve heard several people say that they’ve had problems with it.
Either way, the problem is at least narrowed down.

Thank you everyone for your help!
Dan
 
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Vtx531

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One more thing to check that is quick and easy- check that the pinion nut is torqued. 160-200 ft lb

A loose pinion nut can cause vibrations like you describe.

Maybe you can check the tcase output before replacing it... You should be able to visually see if it is bent. You already have the shaft out, make sure it is in 2wd and put it in drive or first gear and idle. You would see a wobble. You could also spin it with your hand and measure wih a dial indicator. Hate to see you spend a lot of time and money that won’t fix your problem.
 
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d.markowski

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One more thing to check that is quick and easy- check that the pinion nut is torqued. 160-200 ft lb

A loose pinion nut can cause vibrations like you describe.

Maybe you can check the tcase output before replacing it... You should be able to visually see if it is bent. You already have the shaft out, make sure it is in 2wd and put it in drive or first gear and idle. You would see a wobble. You could also spin it with your hand and measure wih a dial indicator. Hate to see you spend a lot of time and money that won’t fix your problem.
True. Thanks. I had a regear done 2 years ago. Vibration was well before this. So I’m gonna rule out the pinion nut but it doesn’t hurt to check it while the driveshaft is out.
I’m going to get a dial indicator and check but place I took my driveshaft to a shop and they said ujoint showed signs of wear from overtightened ubolts and should be replaced. Hopefully that’s all it is. I’ll know later today.
 
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rraulston

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I'm going through the same thing.....what an expensive pain.....I did find that my front 44 diff was bent so that was a good catch, but it still vibrates even after the shop straightened it...
 

Jerry Bransford

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I'm going through the same thing.....what an expensive pain.....I did find that my front 44 diff was bent so that was a good catch, but it still vibrates even after the shop straightened it...
Is its pinion angle directly in line with the driveshaft as it must be? It won't tolerate being out of line much without vibrating.
 

rraulston

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Is its pinion angle directly in line with the driveshaft as it must be? It won't tolerate being out of line much without vibrating.
2005 TJ Rubicon, 3" lift, 285/70-17 tires

Starting with the front:

straightened front Rubi 44 diff, new seals new axel u-joints.
front driveshaft rebuilt and balanced. .004 runout.
rebuilt trans
rebuilt engine
rebuilt transfer case (all three less that 500 miles)
new wheel bearings

Rear:
New Tom Woods drive shaft
new rear axels and bearings
rear diff is + or - 1' in line with the drive shaft using a gauge
new brakes (all 4)
new motor mounts
new trans mount.
tires and rims new and balanced twice at different Discount Tires with no change.

Things left are to try are:
rear ring and pinion/locker swap out (I have a spare TJ front locker going in the rear.)
new front axels, (I bought a factory set I will swap out)
Drive with no front D-line
Drive with no Rear D-line
Drop skid plate

The vibration starts at 60 and is very rapid and shallow and makes my rear view mirror vibrate causing everything you see blurry. It does not pulse in and out. This was like a frame on rebuild. I rev the engine up in neutral and its smooth as butter, It was balanced with new everything. Dunno.....Guess i'm going to go drive my Gladiator to work tonight and keep at it.. Thanks
 

Jerry Bransford

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Good bunch of information but you didn't answer to say if your front pinion angle is in line with the driveshaft.

Remove the front driveshaft, or disconnect it at the front & hang it with cord or zip-ties, and see if the vibration is still there. The front pinion and driveshaft spins 100% of the time so it can definitely cause drivetrain vibes if the pinion angle is excessive.
 
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d.markowski

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The rebalance of driveshaft didn’t work. Nor did the replaced ujoint. I’m completely running out of options. Last option is my transfer case rear output shaft. It is a little noisy back there. Tbh idk what normal sounds like either. If that doesn’t work I’m stuck. At least I know it’s in the rear.....🙄

Pinion angle is a -1.0 to 0.5 degrees (0.5 degree axle pointed down compared to ds angle)
 

rraulston

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Good bunch of information but you didn't answer to say if your front pinion angle is in line with the driveshaft.

Remove the front driveshaft, or disconnect it at the front & hang it with cord or zip-ties, and see if the vibration is still there. The front pinion and driveshaft spins 100% of the time so it can definitely cause drivetrain vibes if the pinion angle is excessive.
ok, ill do that today, also, is there a reason I cant remove the front axels and drive it? The front wheel bearings are isolated right?, maybe stuff a tight rag in each tube? I am putting new u joints in a spare set a guy gave me incase mine are bent....
 
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d.markowski

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ok, ill do that today, also, is there a reason I cant remove the front axels and drive it? The front wheel bearings are isolated right?, maybe stuff a tight rag in each tube? I am putting new u joints in a spare set a guy gave me incase mine are bent....
I think isolating between a front or rear vibration is most important at first. If you suspect it is the front, remove your rear driveshaft and drive it in 4WD. If it doesn't go away, then try removing the front. This is how I isolated my problem to the rear driveline. Then you can also rule out bent axles, wheel bearings, etc if it goes away.
 

Jerry Bransford

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ok, ill do that today, also, is there a reason I cant remove the front axels and drive it? The front wheel bearings are isolated right?, maybe stuff a tight rag in each tube? I am putting new u joints in a spare set a guy gave me incase mine are bent....
Removing the front driveshaft or disconnecting it at its front would certainly be a much better/easier/faster way to isolate the cause to the front or rear than removing the axle shafts.
 

rraulston

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WOW....so here we go....

I remember when I was 17 and couldn't get my VW Baja Bug to run. New points and condenser on and on.... 3 weeks and all local top notch mechanics couldn't either. Put ANOTHER condenser on and it fired right up. Yep, new parts can be bad out of the box..

Fast forward to today. I tried everything. Changed everything and rebuilt FREAKING everything to find the vibration..... And I follow your advice and remove the front drive shaft. You know, the one I just had rebuilt and had balanced by the local shop. All painted black with red arrow stickers pointing at each other, with new weights welded on, Yea, that drive shaft... Then go for a spin 65....75....85... NOTHING!! THAT POS WAS THE SOURCE OF THE VIBRATIONS! Cant make it up.... This took me right back to my old VW..... New custom shaft will be here Friday..... 😑
 
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d.markowski

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WOW....so here we go....

I remember when I was 17 and couldn't get my VW Baja Bug to run. New points and condenser on and on.... 3 weeks and all local top notch mechanics couldn't either. Put ANOTHER condenser on and it fired right up. Yep, new parts can be bad out of the box..

Fast forward to today. I tried everything. Changed everything and rebuilt FREAKING everything to find the vibration..... And I follow your advice and remove the front drive shaft. You know, the one I just had rebuilt and had balanced by the local shop. All painted black with red arrow stickers pointing at each other, with new weights welded on, Yea, that drive shaft... Then go for a spin 65....75....85... NOTHING!! THAT POS WAS THE SOURCE OF THE VIBRATIONS! Cant make it up.... This took me right back to my old VW..... New custom shaft will be here Friday..... 😑
Glad you figured it out! That sure is frustrating but just be happy you aren’t in my shoes. I’m still scratching my head. All I know is that it’s in the rear. Anyone want to come take a look?!! LOL
 

rraulston

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Glad you figured it out! That sure is frustrating but just be happy you aren’t in my shoes. I’m still scratching my head. All I know is that it’s in the rear. Anyone want to come take a look?!! LOL
When I was checking the rear on mine, I jacked it up and ran the jeep up to 80. Vibrated a bit. Then I let it idle at about 25 MPH and saw my right side tire/rim wobble....axel shaft bent. Replaced. Still vibrated. rebalanced tires. New drive shaft. Every little thing helped but didn't fix the entire issue. Now I had a vibration on a Ram years ago and it was a leaking wheel cylinder. That wet spot on the drum created a drag/grab causing it to vibrate... it was even worse under braking.