Launch shudder when towing

[Hoefler]

I have a one piece drive shaft, no carrier bearing. They tried to shim mine with out any luck. I think my problem is in the transmission, they don't believe me. They told me run it till it burns up, then it will be obvious.

 

[roperteacher]

Good God, what is this Crap with Dodge telling people to " Burn it up" then we'll fix. Thats what they told me 2 weeks a go with regards to my water pumps taking a dive every 3,000 miles when it wouldn't puke coolant in front of them " Run it until it quits and we will replace it". . Yea, I am sure they want to replace a whole 6,000 burned up engine because of a 200 water pump they should have looked closer into!!!!

 

[Hoefler]

I think that they are gambling it may not go down until after the warranty is out.

 

[JEstes]

Under the rear springs on top of the spring perch. Loosen spring u-bolts, raise truck by the frame until the axle hangs by the bolts, slide in the shim, re-tighten bolts, lower jack and check your angles.

I getcha... I take it the shims are tapered so it basically rotates the rear end?

 

[Briman]

There is no room under the spring pack to safely run shims. The pin that locates the spring pack to the axle is very short. I did this in an '03 that had the hard to fix vibration. I did not feel it was very safe. Shim the center bearing. You can make a shim quite easily. I did not have launch shudder with a TT and before airbags. My shudder started after I installed airbags and kept the truck level front to rear. I made a shim from 3/4 inch thick bar stock and stuck it between the center bearing and center bearing mount. Works well now. It's very strange to me that the same kind of trucks can require different fixes for the same problem. Is that because of quality control, or maybe differences between model years?

 

[Hoefler]

I getcha... I take it the shims are tapered so it basically rotates the rear end?

Correct, they come in different degrees, usually 1,2,5, and 10.

 

[Briman]

A stock shim (what ever degree) must be modified. At least the one I bought needed to be. The shim I got was 3" x 6". I had to drill 13/16 holes, 1 7/16" & 4 5/8 from the thick end of the shim. I ended up taking the shims out and DC bought back the truck. I tried a 2 and 5 degree.

 

[Hoefler]

If they are just putting the shims and sending you out to try it, they are not doing what they are suppose to do. The procedure is to do a angularity check. You are suppose to check the angles at every joint by using a magnetic adjustable protractor. The angle is checked on the transmission, all drive shafts, and the rear end. This should be done with the intended load on the truck. The angle for every joint is supposed to be between 1/2* and 3*. The angle is changed by installing shims in the transmission mount, carrier bearings, and rear axle springs. It is not as simple as shimming one or two points, if not done properly, you can make it worse or even cause a u-joint failure.

 

[Cattletrkr]

They shimmed mine up and down and every which way. Nothing helped. I fought the shudder for 55K. Finally the center bearing and center ujoint went out, taking the new (10K) rear joint with them. When they were boxing up the parts to send them to DC for warranty purposes, they noticed a needle impression in one of the caps from the center joint, meaning it had been assembled wrong at the factory. I made it 55K with a bad u-joint and now the launch shudder has been almost completely gone since.

 

[231jasonS]

Dodge parts. There is a TSB dealing with launch shudder.

Does any one have the TSB # for this. I was at dealer today and they claim to find no TSB for this.

 

[Lorenz]

TSB 03-003-04 Launch shudder

 

[mfrost]

It came with launch shudder and after I removed the spacers on top of the spring perch to lower the bed for my 5th wheel it went away even when towing. My last trip with with the 5th wheel I had shudder. It seemed like it was only when I was just so slightly off of straight ahead. The only change,as I think about it, was I changed rear diff fluid back to stock that has the LS additive in it, Said the parts man. Before that I was running 75-140 and no shudder. Checked my u-joints and they appear to be OK. Have 46K on it now. No load no shudder.

 

[JCasper]

I have not even worried about my shudder all summer now. I added airbags since a lot of peole said it helped. Yeah it didn't change much.



I think I may space down my center carrier bearing this winter when I get some free time. I will just make some spacers at work to do it.



If that doesn't help I am thinking that traction bars are what is needed.



All summer towing I have just tried to stay light on the throttle until I hit 4th gear. It seems to not be noticed from 4th up.

 

[TAbbott]

I have airbags and they helped but here is what cured the shudder on my 2500. It has zero shudder now, towing or not. First, I did the Klenger mod to my rear springs. That's remove the 3 spacer leaves from the spring stack and place them on top of the spring stack, direcltly under the plate. This lowers the rear end by 1. 5". That eliminated most of the shudder when empty. Still got it loaded, no matter what I did with pressure in the bags. What cured it was a set of Tuff Country traction bars from J. C. Whitney. Essentially, the addition of these bars turns the rear suspension into a 4 link. The rear axle housing can no longer rotate or "wrap" the springs. That keeps the joints from binding and voila, no more launch shudder. It also helped a great deal with the shifting because there is no more spring wrap under torque. It works. No more shudder at all, under any conditions that I've been able to find. And thats with 35" tall tires, a gvw of 23500+ and a G-56.

 

[mfrost]

I have airbags and they helped but here is what cured the shudder on my 2500. It has zero shudder now, towing or not. First, I did the Klenger mod to my rear springs. That's remove the 3 spacer leaves from the spring stack and place them on top of the spring stack, direcltly under the plate. This lowers the rear end by 1. 5". That eliminated most of the shudder when empty. Still got it loaded, no matter what I did with pressure in the bags. What cured it was a set of Tuff Country traction bars from J. C. Whitney. Essentially, the addition of these bars turns the rear suspension into a 4 link. The rear axle housing can no longer rotate or "wrap" the springs. That keeps the joints from binding and voila, no more launch shudder. It also helped a great deal with the shifting because there is no more spring wrap under torque. It works. No more shudder at all, under any conditions that I've been able to find. And thats with 35" tall tires, a gvw of 23500+ and a G-56.

Are those the bars that attach to the top of the spring pack and go to an owner drilled hole in the front spring mounting bracket?. If it is not bad for $150.

 

[TAbbott]

Yes. They attach to the top of the u-bolts on top of the upper plate and go to a 7/8ths hole you drill in the front spring hanger. 7/8ths step drill works well for the hole. Pretty easy install, price was $149. 00 I think (saw them later on sale for something like $65. 00 @ Whitney) so is a pretty cheap fix. More to the point though, is launch shudder is gone.

 

[mfrost]

TAbbot, Thanks I think I will give them a try.

 

[TAbbott]

I hope they work as well for you as they did for me. Good luck... .