75 mph vibrations.

[okiemoto]

Ok, so this is my first post here. Found the forum from ordering parts from Geno's.

I have a 2003 2500 4x4 quad cab short bed Laramie. I have a vibration issue that occurs 72-75 mph. The vibration is not present with the front driveshaft removed. Truck drives absolutely perfect without the front driveshaft installed.

I've owned the truck 4 months now and have had a driveshaft shop install new joints and rebalance both front and rear shafts. Having the front driveshaft rebuilt and balanced certainly lessened the vibrations i was experiencing although definitely still there. That was a month or so ago.

Around a week ago my wife drove the truck and I rode in the passenger side for the first time and noticed the intensity and frequency of the vibration was more prevalent on this side. The vibration is a low, fast frequency typically associated with a bad u joint.

Today I pulled the passenger front axle and had the joint replaced as the old one was a cheap precision joint and felt extremely notchy. Noticed no change in vibration. Basically the only u joint that hasnt been touched is drivers front axle joint but it has a Spicer or an aam joint and appears to be new.

I've called a popular 4x4 shop in my area to see about having them find and fix the issue but was told hed gladly look at it but is not interested in taking the job. He said vibrations are not fun for anyone not the customer not the business.

I've been all over the internet reading every thread I can come across but any forum post seems to deadend like people dont come back and state what their issue was or how they found it.

What's next on the list to check? Anyone had similar issues and fixed it? Thanks for any help

 

[GrantP]

It sounds like you've already isolated it to the front driveshaft. Don't assume the driveshaft shop that did the work did it correctly. I went through this on an old Jeep XJ with multiple local driveshaft shops. Each one tried twice to get it right, the only thing that ever changed was the pitch or the speed at which the vibration occurred. I finally sent it off to Tom Woods, it was re-tubed and balanced at a very reasonable cost. Problem solved.

 

[okiemoto]

I'd love to think that was the issue. I've had the front shaft done twice by 2 different shops 1000 miles apart. First time with neapco greasables and balanced. Upon picking it up I noticed quite a bit if weight on it and was not quite sure it was done correctly.

So I had another shop go through it. They said it's way too much weight somethings not right. They tore it down and reinspected and put spicer non greasables in. I watched it set up in their balancer spinning at 3,000 rpm with a dial indicator set up at both ends after they balanced it. .001-.0015 variance at either end.

Regardless I'm 500 or so dollars in to the front driveshaft. Kinda hard to spend more money on it and it not be the issue.

Thank you for your input and I will look this fella up and contact him to get his opinion.

 

[Ozymandias]

It can be as good the rear drive shaft that is to blame.
It happened to me the same way.
Check the rear shaft first before spending any more money on the front end.

 

[Ozymandias]

And it needs to be high speed balanced.
3000rpm is at least 1000 to low for this application.

 

[cerberusiam]

Have you looked at the t-case? Haver you rebuilt it? If you have any slack anywhere in it that will translate to vibes. Front diff also with DS attached will show problems not there without it.

 

[Ozymandias]

By the way, for 500.-$ you could have gotten a brand new shaft from the factory.
Keep this in mind for the rear one.

 

[okiemoto]

Rear driveshaft has been rebuilt. Transfer case was "rebuilt" before I purchased it. Only proof I have of that is that the case is clean and the output feels tight. No obvious play there or at the diff end.

As far as 3k not being high enough speed this truck is stone stock. No lift stock tire size. Driveshaft speed calculations show the vibe happening around 2900 if I remember correctly.

And the factory front driveshaft is no longer available from dodge.

As far as bearings in the diff go I have had a pinion bearing going out on a truck before and it made a god awful growling noise. No noise from this one. Also no obvious play in companion flange.

Think that answers most of the replies. I also just got off the phone with Shaun at Tom Woods. He went through about a 20 minute conversation with me. He didnt sound entirely convinced it is the driveshaft.

 

[GCroyle]

Current issue of TDR magazine has a vibration analyzer app. Here is creators video about it.

 

[okiemoto]

Haha! I literally just watched that video on youtube! The app is one easy payment of 399.99. My current plan of action is to go ahead and do the drivers axle joint as it's the last u joint and all of em will be brand new. So far they've all been bad but have not fixed the issue.

 

[Ozymandias]

Of course is the driveshaft available, it is superceded and has a new part#. 52123326AB
It has now 3x 1350 u-joints. Way bigger then what it had from factory.

 

[okiemoto]

Ozymandias. I have called 2 different local dealers, one being in a network of dealers that a friend is employed at. Their dodge parts guy said the part has been discontinued. As well as an online fiche. None list that part supercession that you referenced there.

Regardless, I dont want to spend more money on the front shaft to have it not be the issue. I have seen with my own 2 eyes the shaft on the balancer. That 30 pound shaft spinning 3000 rpm and only having a thousandth of an inch of variance all but confirms the shaft isn't the problem. I'm open to ideas but cant spend more money on this driveshaft without being absolutely positive it is the issue. Ic I had another shaft I could swap and that alleviated the issue I would happily purchase a new shaft if indeed it was available.

 

[Jasonmm]

I get the same vibration at about the same speed but mine kinda pulsates. I very rarely go on the highway so I haven’t personally looked at it yet. Interested in seeing what you ultimately find

 

[okiemoto]

I will certainly update the thread when I figure it out. It may be a long drawn out process though.

 

[Ozymandias]

The only other thing that I can think off is that the front u-joint is out of alignment.
It needs to have 179°-181° angle, if it is off it can start Vibs.
That angle is changed together with the Caster, if the caster is at around 4° on a stock, non lifted, vehicle then the u-joint angle is also in spec.

Another point can be broken down motor mounts, happens often. Then the Engine/Transmission unit doesnt align with the axles anymore and therefore can vibrate to.

 

[AEdelheit]

OZY beat me to it but as he mentioned dont overlook caster, too much or too little and it will throw off the front U joint angle.

 

[sag2]

Don't waste your time with the other front shaft. It spins all the time so when you remove the front drive line and it's gone it eliminates the axles. Start by installing the front shaft and dial indicate the ends making sure you have no more than .007 runout on either end. Also check the front axle flange, it should be very close to zero runout. There was a problem with some of the Jeep axles (Dana) that had what they called pitch line runout. It is actually the pinion shaft that is slightly bent and will give you excessive runout. If the runout of the shaft is not correct, rotate the ends of the shaft 180° in the front or rear flange and recheck. Once you have the assembled runout as low as possible it is time to get out the hose clamps and balance the assembly going down the road at the speed the vibration occurs. Mark the front of the shaft and install one clamp with the head at the mark. Drive and using your assometer (unless you purchase the tool reviewed in issue 109) determine better/worse. Stop and move the clamp 90° and drive again. Repeat until you have moved the clamp three times. Note best location. If it seems to stay the same move the clamp to the rear of the shaft and repeat noting better/worse for each location.
If you can't get it any better, it is time to perform the same procedure on the rear shaft. Again runout should be .007 or less on both ends. The transfer case end will have some slop, so turn the shaft with the tire, not by grabbing the shaft. Again move the ends 180° to get the least runout. Now that you have the assembled runout correct start with the hose clamp (you may need to order a couple large enough diameter) at the rear of the shaft. Perform the same steps as with the front noting better worse. If you can't get it better move to front of shaft and repeat. If you get it best at any location, add a second clamp at that location and then start splitting apart the head locations to try and fine tune it. I have repaired more than a few trucks that you would swear was caused by the front by balancing the rear shaft. The vibration you are feeling is usually caused by the interaction of the normal third order engine firing frequency with a first order drive line vibration.
If you get it better/perfect just leave the clamps on it and drive it. I tried several trucks where I measured the clamp head weight and had the drive shaft shop weld equivalent weight on with poor results. I can't explain it, but that's how it worked.
A big piece of cardboard and a nut driver helps when you are crawling under the truck on the side of the freeway.

 

[sag2]

The only other thing that I can think off is that the front u-joint is out of alignment.
It needs to have 179°-181° angle, if it is off it can start Vibs.
That angle is changed together with the Caster, if the caster is at around 4° on a stock, non lifted, vehicle then the u-joint angle is also in spec.

Another point can be broken down motor mounts, happens often. Then the Engine/Transmission unit doesnt align with the axles anymore and therefore can vibrate to.

He beat me to it also as I was typing. If the vibration is a second order (caused by angle, not balance) you have to correct the angle problem first before trying the balance procedure. That is where the vibration analyzer comes in handy, in determining the type of vibration first. You can't fix a second order (angle) vibration with balance (first order).

 

[okiemoto]

Definitely something to chew on. I've noticed I can accelerate through the vibration and it isnt noticeable but when decelerating through the area with my foot off the throttle I do notice it. That leads me to think maybe an angle issue?

I will try to figure out how to measure pinion angle and maybe try to schedule an alignment one day this week. I think now we might be getting into something. I will try to have some angle measurements up this evening if it quits raining. Thanks for your help fellas.

 

[okiemoto]

Don't waste your time with the other front shaft. It spins all the time so when you remove the front drive line and it's gone it eliminates the axles. Start by installing the front shaft and dial indicate the ends making sure you have no more than .007 runout on either end. Also check the front axle flange, it should be very close to zero runout. There was a problem with some of the Jeep axles (Dana) that had what they called pitch line runout. It is actually the pinion shaft that is slightly bent and will give you excessive runout. If the runout of the shaft is not correct, rotate the ends of the shaft 180° in the front or rear flange and recheck. Once you have the assembled runout as low as possible it is time to get out the hose clamps and balance the assembly going down the road at the speed the vibration occurs. Mark the front of the shaft and install one clamp with the head at the mark. Drive and using your assometer (unless you purchase the tool reviewed in issue 109) determine better/worse. Stop and move the clamp 90° and drive again. Repeat until you have moved the clamp three times. Note best location. If it seems to stay the same move the clamp to the rear of the shaft and repeat noting better/worse for each location.
If you can't get it any better, it is time to perform the same procedure on the rear shaft. Again runout should be .007 or less on both ends. The transfer case end will have some slop, so turn the shaft with the tire, not by grabbing the shaft. Again move the ends 180° to get the least runout. Now that you have the assembled runout correct start with the hose clamp (you may need to order a couple large enough diameter) at the rear of the shaft. Perform the same steps as with the front noting better worse. If you can't get it better move to front of shaft and repeat. If you get it best at any location, add a second clamp at that location and then start splitting apart the head locations to try and fine tune it. I have repaired more than a few trucks that you would swear was caused by the front by balancing the rear shaft. The vibration you are feeling is usually caused by the interaction of the normal third order engine firing frequency with a first order drive line vibration.
If you get it better/perfect just leave the clamps on it and drive it. I tried several trucks where I measured the clamp head weight and had the drive shaft shop weld equivalent weight on with poor results. I can't explain it, but that's how it worked.
A big piece of cardboard and a nut driver helps when you are crawling under the truck on the side of the freeway.

You posted as I was typing my previous response. I will get a dial indicator and check runout. If I'm not mistaken thiugh you can not "phase" the front driveshaft. It makes up to the companion flange in only one orientation I'm pretty sure. Will definitely check and advise as I have time.