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General Forums => The Mess Hall => Topic started by: bootguy on February 15, 2015, 10:27:58 AM

Title: CV Drive shafts
Post by: bootguy on February 15, 2015, 10:27:58 AM
I have noise in both the transfer case and the pumpkins at around 40 - 50 mph.  Have rebuilt the transfer case and checked both pumpkins and put in new U-joints.  Finally got fed up and took it in to the local 4WD shop.  They said it was normal and the only way to get less noise was going to CV drive shafts.  I do plan on going to a Ford 8.8 rear end with the C clip eliminator and new axles up front while removing the vacuum disconnect. This summer I plan on rhino lining the tub to also help reduce road noise.  So the question is has anyone gone to the CV drive shafts and if so have they reduced road noise?
Title: Re: CV Drive shafts
Post by: Jeffy on February 23, 2015, 03:20:47 PM
Many people have gone to CV.  As for getting rid of noise, it really depends.  If you're on a stock suspension, and go with a CV, you'll likely have no difference.  If you're at a severe angle and it sounds like a can of ball bearings rolling around every time you let off the throttle, then yes it will make a difference.  Generally speaking though the reason for going with a CV driveshaft is not for noise though that's a bi-product.
Title: Re: CV Drive shafts
Post by: bootguy on February 28, 2015, 08:51:59 AM
Most of my drive is at 45 MPH and that is the sweet spot for the noise.  Only have 2.5" lift (professionally installed), so there is not a severe angle.  I will have to replace the rear drive shaft when I replace the rear axle and go with the SYE kit and plan on going to CV drive shat at that time as it is not really that much more.  The front shaft though is the problem child, Will just have to save a little more and do that one also.
Title: Re: CV Drive shafts
Post by: Jeffy on February 28, 2015, 11:49:19 AM
Unless you have a front locker or a LSD, the front driveshaft does not turn unless you're in 4WD.
Title: Re: CV Drive shafts
Post by: bootguy on March 04, 2015, 09:46:26 PM
Rolling down the road the drive shaft turns.  Up on blocks the wheels do not turn.  The front end was re-geared a few years ago but no locker put in and do not think it was LSD.  This next week will be upgrading the front axles and getting rid of the vacuum disconnect.
Title: Re: CV Drive shafts
Post by: sharpxmen on March 05, 2015, 07:43:24 AM
Rolling down the road the drive shaft turns.  Up on blocks the wheels do not turn.  The front end was re-geared a few years ago but no locker put in and do not think it was LSD.  This next week will be upgrading the front axles and getting rid of the vacuum disconnect.
it shouldn't turn, something's wrong with the quick disconnect on the passenger side (unless you have a 1 piece shaft there) or maybe you have a locker of sorts or LSD like Jeffy said.
Title: Re: CV Drive shafts
Post by: Jeffy on March 05, 2015, 02:28:33 PM
I bet someone put the vacuum disconnect plug on backwards.  Which is why you get a noise and probably vibrations at 40-50.  That's about where you'll start to feel vibrations from the front shaft turning.

The line should look like this:

(http://i4.photobucket.com/albums/y118/yokomura/4BangerJP/axle/disconnect/3f1f464b.jpg)
Title: Re: CV Drive shafts
Post by: AWK on March 06, 2015, 09:53:13 AM
Would this be the same for a 97 TJ?  I am thinking mine turns.

AWK
Title: Re: CV Drive shafts
Post by: Jeffy on March 06, 2015, 12:17:21 PM
Would this be the same for a 97 TJ?  I am thinking mine turns.

AWK
No, TJ's are different.  They don't have a disconnect and so it turns.
Title: Re: CV Drive shafts
Post by: bootguy on March 06, 2015, 06:56:56 PM
Am going to go look at the Vacuum lines tomorrow, but I have a set of solid axles going in next week.  Will have a better overall picture once I get this work done.
Title: Re: CV Drive shafts
Post by: Jeffy on March 06, 2015, 08:09:55 PM
A one-piece axle shaft will make the driveshaft spin as well.
Title: Re: CV Drive shafts
Post by: jfrabat on March 10, 2015, 11:30:25 AM
Am going to go look at the Vacuum lines tomorrow, but I have a set of solid axles going in next week.  Will have a better overall picture once I get this work done.
With solid axles, as Jeffy said, the shaft will spin.  Just get a balanced shaft and call it good.  I put a Tom Woods shaft on mine when I went to solid axles, and have not had any problems with vibrations...  The rear one I did kill once (wheeling will do that), but never had issues with the front...
Title: Re: CV Drive shafts
Post by: Bounty Hunter on May 06, 2015, 09:59:18 AM
The mechanic that told you to install CV driveshafts to get rid of a noise is an idiot.  Non-CV Driveshafts are quiet if in good condition and your ujoint angles are correct.  I would find a different mechanic to track down the noise before something goes real bad.

You can't install a CV driveshaft up front unless your pinion is pointed directly at the transfer case yoke.  Can't do that unless you cut and turn the inner-C's.
Title: Re: CV Drive shafts
Post by: bootguy on May 11, 2015, 10:11:10 PM
Put in the solid axles and at the same time replaced the U joints again.  road noise was less but with the 2.5" lift I saw that the shaft was extended quite a good 1.5".  I am going to replace the drive shaft, but will have to measure for length.  So a little bit of research to do.
Title: Re: CV Drive shafts
Post by: Bounty Hunter on June 01, 2015, 11:28:18 PM
Put in the solid axles and at the same time replaced the U joints again.  road noise was less but with the 2.5" lift I saw that the shaft was extended quite a good 1.5".  I am going to replace the drive shaft, but will have to measure for length.  So a little bit of research to do.
Make sure the ujoint angles are correct for a non-CV driveshaft.
(http://www.customdriveshafts.com/images/2joint_angle.gif)