Diagnosing noise

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

Charlesthe2nd

Full Access Member
Joined
Jun 8, 2015
Messages
189
Reaction score
12
Location
Portland, ME
I'm currently in the process of trying to figure out what is causing a thumping in my front drivetrain. It started last week and has gotten progressively worse.

Things that have been worked on in the front most recently:
Upper/Lower Ball Joint
Clevish Bushing
Swaybar Bushing
Pass/Driver CV Axle
Intermediate shaft
Differential Gears and ARB service

When they put everything back together there was a bad vibration. Did the 500mi gear break-in and explained the vibration, and they proceeded to go through all the various parts of the drivetrain and tracked it back to the front driveshaft. It had been put back on, but not fully torqued which caused a vibration that increased with speed. They fixed it and all was well.

Currently, the thumping vibration is very noticeable in the 30-45mph range then decreases but can still be felt. It is coming through the floor and gas pedal, and cannot be felt in the steering wheel. It's in the driveway, on jack stands with the front wheels off. I have today and tomorrow off and would like to get this fixed asap.

I believe it's the drive shaft, but honestly don't know. Differential spins freely forward and back, and the CV doesn't sound like it's binding.

Turning Driver CV

Turning Front Driveshaft

You must be registered for see images attach

You must be registered for see images attach

You must be registered for see images attach

You must be registered for see images attach
 

Charlesthe2nd

Full Access Member
Joined
Jun 8, 2015
Messages
189
Reaction score
12
Location
Portland, ME
Not really sure why my front driveshaft has U-Joints vs the more common CV style. Anyone care to take a stab at that even. Could a failing u-joint cause a vibration like that?
 

mrlavalamp

Full Access Member
Joined
Jul 12, 2017
Messages
201
Reaction score
52
Location
Sin City
Do you need to use your 4 wheel drive?

I would try removing the front driveshaft and see if the noise is still there.

This will also give you the chance to take apart the joint and see what condition it is in. If you go this far with it, you may as well just put in new ones anyways, as they are about $20 each and if they aren't worn out yet, they will eventually.

I like to use the greasable joints, but I don't replace enough of them to comment on how they effect the longevity of the part. For me it is just peace of mind that I can stick a grease gun on it and lube it each oil change. In theory they should last longer.
 

HoosierJeeper

Gold Supporter/Admin
Staff member
Administrator
Joined
Jan 20, 2009
Messages
20,855
Reaction score
266
Location
Western WI
I'd remove the front shaft, that is weird about it having U joints. I've never heard of someone having a good time when they have swapped to U joints up front. I'd get the CV style one back in there.
 

Charlesthe2nd

Full Access Member
Joined
Jun 8, 2015
Messages
189
Reaction score
12
Location
Portland, ME
Do you need to use your 4 wheel drive?

I would try removing the front driveshaft and see if the noise is still there.

This will also give you the chance to take apart the joint and see what condition it is in. If you go this far with it, you may as well just put in new ones anyways, as they are about $20 each and if they aren't worn out yet, they will eventually.

I like to use the greasable joints, but I don't replace enough of them to comment on how they effect the longevity of the part. For me it is just peace of mind that I can stick a grease gun on it and lube it each oil change. In theory they should last longer.

I'd remove the front shaft, that is weird about it having U joints. I've never heard of someone having a good time when they have swapped to U joints up front. I'd get the CV style one back in there.

I dont currently need 4wd, so out with the driveshaft it is. Not sure what the SOP for driveshaft removal is so I'll have to look into that. Yea, the greaseable joints do sound good, also conversely it is not stock. Is it better than stock, or worse, because I'd rather not have to purchase a new driveshaft. If I'm recalling correctly, then the driveshaft has probably been in there for almost a decade without giving me any issues.
 

mrlavalamp

Full Access Member
Joined
Jul 12, 2017
Messages
201
Reaction score
52
Location
Sin City
Pretty easy to remove. I would spray it with a rust penetrant let it soak a bit and then simply unbolt each end from the flanges on the diff/ t-case. Might take a little gentle suggestion with a hammer as the flanges are likely rusted together a little.

I'm no expert but since you aren't getting many responses my thoughts are the U-joint may cause parts to wear or stress differently vs. the original CV design, there is a reason jeep used CV's here and not U-joints.

New front driveshafts can be had for $200 or less (on ebay) or $300 on rockauto. A trip to your local junkyard may be a more frugal approach.

You mention that its been in for a decade and no issues yet, replacing the joints will get you back to usable 4wd for the least dough and you may be just fine with it.
 
Last edited:

Charlesthe2nd

Full Access Member
Joined
Jun 8, 2015
Messages
189
Reaction score
12
Location
Portland, ME
I'd say worse than stock.

I've always had problems with my front cv axles, and intermediate shaft. To the extent where I am on my 7th or 8th set since the life of the vehicle. It has been my bain. I'm curious if the driveshaft could play a role in that.

Pretty easy to remove. I would spray it with a rust penetrant let it soak a bit and then simply unbolt each end from the flanges on the diff/ t-case. Might take a little gentle suggestion with a hammer as the flanges are likely rusted together a little.

I'm no expert but since you aren't getting many responses my thoughts are the U-joint may cause parts to wear or stress differently vs. the original CV design, there is a reason jeep used CV's here and not U-joints.

New front driveshafts can be had for $200 or less (on ebay) or $300 on rockauto. A trip to your local junkyard may be a more frugal approach.

You mention that its been in for a decade and no issues yet, replacing the joints will get you back to usable 4wd for the least dough and you may be just fine with it.

I've been busy here, working 12 hour days for the past 2 weeks, exhausted is an understatement. I got under the Jeep on Saturday. The driveshaft seemed easy to remove, I was almost done and then I stripped the last 2 of the 6 Allen key bolts going into the front diff. Proceeded to replace all the ones I took out.

Finding a junkyard with an 02-04 liberty is on my to-do list this week. Would be happy to take a used driveshaft, amongst other things that she needs.

The thump has gotten worse, and at this point, I'm not sure what it is. Guess that it could very well be the intermediate shaft. I'm really hoping that this isn't emanating from the differential, but it feels like that's the area it comes from. The vibration comes through the floor and pedal, increases in intensity at 30-45mph then becomes less noticeable at the 55-65mph range.
 

tommudd

Moderator
Staff member
Moderator
Joined
Jul 14, 2005
Messages
22,456
Reaction score
3,642
Location
Southeastern Ohio
If it has u-joints in the front everyone I have seen does make some vibrations
Those who thought it was an upgrade did not like that upgrade
Had an almost new one laying in the garage till it went to the junk yard a couple of years back.
The u-joints are not on the right plane to not vibrate, reason they went to the CVs, well one of the reasons
 

Latest posts

Top