Removing rear driveshaft to test for vibes

DUB

DUB

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I have a droning vibe at 65+ that is a constant off on, off on... Is it really okay to remove the rear DS and test drive at these speeds? This is only provided that my front DS removal test doesn't work. I do have an SYE and DC rear shaft and have setup as discussed on the forum. Not convinced that it isn't just the nature of my NV3350?
 
Yes it is really okay. According to WTJF code, section 4, article 15 (b), exception (2), temporary removal of the rear driveshaft for NVH diagnosis is one of only two acceptable cases of a FWD Jeep (the other being a front dig).


Just kidding, but yes it’s fine. Due to the nature of the front u-joints, tight turns under acceleration will be wonky, so go easy there. I’d guess the vibration source is probably the pinion angle.
 
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Tob said:
Yes it is really okay. According to WTJF code, section 4, article 15 (b), exception (2), temporary removal of the rear driveshaft for NVH diagnosis is one of only two acceptable cases of a FWD Jeep (the other being a front dig).


Just kidding, but yes it’s fine. Due to the nature of the front u-joints, tight turns under acceleration will be wonky, so go easy there. I’d guess the vibration source is probably the pinion angle.
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LOL, thanks man! I'm hoping that's it but I thought I had it pretty dialed in.
 
DUB said:
I have a droning vibe at 65+ that is a constant off on, off on... Is it really okay to remove the rear DS and test drive at these speeds? This is only provided that my front DS removal test doesn't work. I do have an SYE and DC rear shaft and have setup as discussed on the forum. Not convinced that it isn't just the nature of my NV3350?
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The drone/oscillation happened to me after regearing from 4.10 to 5.13. There's a thread or 2 on the oscillation problem with tons of detail.

I was odd man out and mine was cured with a driveshaft balance (aftermarket) locally.
 
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NOTNSUV said:
The drone/oscillation happened to me after regearing from 4.10 to 5.13. There's a thread or 2 on the oscillation problem with tons of detail.

I was odd man out and mine was cured with a driveshaft balance (aftermarket) locally.
Click to expand...

Well I will say that I did just regear to 4.56... Put on the SYE at the same time. I did buy a cheapo driveshaft though. I want to say that I have always had this droning issue and it is not RPM based, it's speed based.
 
I had it too. It was on, off, on, off, just like you said. It went away when either the front or rear drive shaft was removed. I had the front drive shaft rebalanced and that improved it slightly. I finally replaced the front drive shaft with a new one from Tom Woods and the drone went away completely.
 
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Tob said:
Yes it is really okay. According to WTJF code, section 4, article 15 (b), exception (2), temporary removal of the rear driveshaft for NVH diagnosis is one of only two acceptable cases of a FWD Jeep (the other being a front dig).


Just kidding, but yes it’s fine. Due to the nature of the front u-joints, tight turns under acceleration will be wonky, so go easy there. I’d guess the vibration source is probably the pinion angle.
Click to expand...

👊
 
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I just went through this. Removing rear dshaft made it smooth all speeds, confirming rear driveline vibration. Installed SYE and Tom Woods rear dshaft with DC-smooth now. BTW driveline vibration that’s speed related is driveshaft rpm related (not engine rpm). With the gear change you increased driveshaft rpm at all speeds, front and rear driveshafts, so it is good you are trying to isolate which one.
 
TJBUD said:
I just went through this. Removing rear dshaft made it smooth all speeds, confirming rear driveline vibration. Installed SYE and Tom Woods rear dshaft with DC-smooth now. BTW driveline vibration that’s speed related is driveshaft rpm related (not engine rpm). With the gear change you increased driveshaft rpm at all speeds, front and rear driveshafts, so it is good you are trying to isolate which one.
Click to expand...

I do have a new TW front shaft. Going to remove the rear first and try it out.
 
TurboTJ said:
I had it too. It was on, off, on, off, just like you said. It went away when either the front or rear drive shaft was removed. I had the front drive shaft rebalanced and that improved it slightly. I finally replaced the front drive shaft with a new one from Tom Woods and the drone went away completely.
Click to expand...

I’m curious, if the Jeep is rear wheel drive, why would replacing the front drive shaft fix it? The front is only engaged with 4WD
 
I fairly certain I am currently experiencing the same thing. I’ve had it at the shop and I have people tell me they can’t feel it. I find it hard to believe because I feel it through the pedal.

I described it as vibration, but a droning sound/feel is better for sure. Mine seems to go away when going downhill and get worse under pressure (uphill)

Drives me nuts. If I can help it anyway I will try.
 
LittleGiant said:
I’m curious, if the Jeep is rear wheel drive, why would replacing the front drive shaft fix it? The front is only engaged with 4WD
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Nope. Ther are no hubs on a TJ, therefore if the front tires are spinning so is the diff and the DL. It is only disconnected at the transfer case so it is not driven by the transmission/motor.
 
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chudlet said:
Nope. Ther are no hubs on a TJ, therefore if the front tires are spinning so is the diff and the DL. It is only disconnected at the transfer case so it is not driven by the transmission/motor.
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Ok, just to make sure I’m clear (sorry I’m an idiot) can you just disconnect one end or should you take it completely off? I assume off.
 
The front, you can disconnect the front end of the DL and hang it with safety wire, zip ties, velcro, dealers choice. Which separates it from being driven by the diff. Just be safe about it, should the front of the DL drop from its securing, it becomes a pole vault
 
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If you were to put it in 4wd at this point then the motor starts spinning it. So lots of care and attention to detail
 
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Common sense makes me think this issue can be solved by making sure things are at the correct angle. Could it be as simple as that? (Simple solution, not making it happen haha)
 
TJBUD said:
I just went through this. Removing rear dshaft made it smooth all speeds, confirming rear driveline vibration. Installed SYE and Tom Woods rear dshaft with DC-smooth now. BTW driveline vibration that’s speed related is driveshaft rpm related (not engine rpm). With the gear change you increased driveshaft rpm at all speeds, front and rear driveshafts, so it is good you are trying to isolate which one.
Click to expand...

Stupid question, if you completely remove the rear drive shaft, how do you drive it? Put it 4WD and have the power come from the front? Also, once removed, do you need to do anything in to the areas where it was connected to before driving it?
 
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