03 Driveline Vibration

[Prairie Dog]

Just went out and checked... I can get the first (short) drive line to move in and out of the Xfer case by about 1/4 " but it doesn't clunk. It's more of a heavily damped feeling, I cant get it to move quickly. There's 1/16" of rotational slop and no side to side or up and down movement at all. I can feel the slightest little clunk from the U-joint, which is normal.

PCline, when you said you could feel the xfer case vibrating, did you mean you could feel it through the 4x lever? Mine stays perfectly still.

 

[PCline]

when you said you could feel the xfer case vibrating, did you mean you could feel it through the 4x lever?

At the time I felt the xfer case vibrating I actually had the rear axle on jack stands and my dad was "driving" it for me. I slid under the truck and felt for things shaking. The greates vibrations was felt on the rear portion of the xfer case.



In this thread, https://www.turbodieselregister.com/forums/showthread.php?s=&threadid=67933&highlight=vibration, Sag2 fixed a truck by replacing the extension housing. The extension housing is precisely where I felt the greatest vibration. The dealer told me that there is a bushing in the housing that supports the driveshaft.



I think a loose bushing to shaft fit is what causes the side-to-side clunk some of us feel and produces the high speed vibration.

 

[Steve M]

My 4X2 automatic also has enough side to side or up and down play in the tailshaft of the transmission to cause an audible clunk when I push the drive shaft up and down. May be the same bushing used for both tailshafts... ?

 

[PCline]

I looked in the manual at both the 4X2 transmission tailshaft and the 4X4 Xfer extension housing. They look different externally, but that doesn't mean the same design philosophy wasn't used internally.



The 4X2 picture is attached below. I'll post the 4X4 in the next message.

 

[PCline]

Heres' the 4X4 Xfer case extension housing.

 

[Briman]

I took a Dodge tech for a ride in my truck today. While I was driving I handed him a copy of this thread and the one where SAG2 tells about fixing a truck with a vibration. To make a long story short, the dealer ordered a tail shaft for the transfer case and will swap it out. He also said he would try to get the correct shims for the rear axle, instead of farming that work out.



I also showed him the wobble in 2nd gear and he said all the trucks do it. They replaced a couple of transmissions because of it and new venture sent them back to the dealer as good (the dealer had to eat both trans. ) He said one of the truck owners is mad because the new replacement trans is worse than the original one he had.



This is a large dealership in the Salt Lake City area and their service department is better than the three other Dodge dealerships I have dealt with in the past. I don't know how quick the tail shaft will come in, but will post on the results after it gets done.

 

[Steve M]

My '98 5spd used to wag it's shifter too. I never considered it a problem. I even got into the habit of holding it loosely in my hand just to feel it do it's thing. It shifted smooth and quiet for the 89K miles I owned it.

Back to the vibration. I got my nicked rim replaced today. While they were at it, the mechanic rebalanced and rotated all four tires again. When he did it the first time, I felt like the vibration moved more to the steering wheel and less in the seat. I contributed it to being hyper sensitive from trying to figure it out. Today when he rotated them again, the vibration is back in the seat and floorboard and less in the steering wheel. I think my vibration is a bad tire or wheel.

 

[sag2]

Get the dealer to ask his rep to borrow a vibration analyzer and they can quit guessing.

 

[mark93]

Hey Guys.



I just took delivery of a manual trans HEMI 2500 SWB QC 4X4 with 4. 10 gear and vibration comes on at 68-70 mph then goes away by 75 mph comes back a little at 85 mph or so then is gone at 90 and does not return up to 110 mph.



In my case, if it is not harmful to any components I can live with it as "just he way it is with a HD drivetrain, especially one that has both driveshafts spinning all the time ( I had a First Gen Diesel and "know vibration").

 

[PCline]

Finally fixed my problem!



Bottome line... two problems, a t-case extension housing with a loose fit and bad driveline angles.



I put a more complete description in this post:



https://www.turbodieselregister.com/forums/showthread.php?s=&postid=621539#post621539



If anyone needs help with their driveline angles I found lots of good information on the web I can point you towards. Never found anything specific to a 2 piece driveline, so I actually had to crack open one of my college textbooks and review cardan joints.



There is a fine line between proper cancellation angles and operating angles on these trucks. Cancellation angles should be less than 1 degree and operating angles should be greater than 1/2 degree. I had a difficult time getting enough operating angle on my truck.

 

[Steve M]

As I said in another post, I ran my truck up to 67mph with the rear axle on jack stands. The vibration is the same as when driving. This rules out tires and rims. I believe wishful thinking is blurring my focus. It's obviously a driveline vibration and not engine or tires. If I put the truck in neutral at 70mph and let it coast down, the vibration is there as it passes 68-65mph. The service writer said he drove another truck and verified that it didn't have the vibration. He didn't offer to swap driveshafts and see if the vibration moved from one truck to the other. This would be an easy and cost effective trial. Instead I'll be taking the truck back to the dealership Monday so someone else can drive it and make an assumption. The driveshaft is such a straight shot from the transmission to the pinion, I can't imagine drive line angle being the cause of my truck's vibration. I might try the hose clamp balance method this weekend.

The other thing the service writer said is the truck's drive lines are not set up. They're all the same with regards to drive line and pinion angle. No shims anywhere. So if one truck doesn't vibrate and the next identical truck does, I'd sure like to swap driveshafts with the one that doesn't.

 

[jcarver]

Steve M - don't bother wasting the trip in. They did the same thing to my truck. At first it seemed to have gone away, but as I drove on it was still there. I guess I was just being optimistic. I think others have had this done to no avail. I am waiting for an official repair from DC, although PCline seems to have solved the mystery. Most dealers dont have the techs who will spend the time to try doing what he did. They usually like having an official TSB in hand before making such repairs.

 

[PCline]

The driveshaft is such a straight shot from the transmission to the pinion, I can't imagine drive line angle being the cause of my truck's vibration

Steve... in the case of a driveline a straight shot is not a good thing. You need some operating angle to provide cancellation. Cancellation is required because a driveshaft (at least the part between the u-joints) does not rotate at a constant velocity. This web page has a much better description than I could ever write here. It even describes how to make the measurements yourself.



http://www.classictruckshop.com/t4.htm



I also have a Windows Media clip that shows graphically how the center of the driveshaft speeds up and slows down. I can't take credit for it because I found it on the web but now I don't remember where I found it. If anyone wants it, PM me and I'll send it to you.



In the case of our 2 piece driveshafts, the front half should come straight out of the t-case (or transmission), then the rear half should angle towards the pinion. There are 3 u-joints. The front u-joint should have zero operating angle, the mid u-joint should have AT LEAST 1/2 degree operating angle and the rear u-joint should have the same operating angle as the mid. Because the front u-joint has no operating angle the front half of the driveshaft will turn at a constant velocity. The rear half is NOT turning at a constant velocity but the mid and rear u-joints are canceling each other so the pinion IS turning at a constant velocity.



In the case of your truck I can almost guarantee the front and rear halves are trying to fight each other because of poor cancellation.