Launch Shudder when towing

[CFulton]

As an update took 5th to dealer for them to experience the shudder said need to shim the center point to change the drive angle. 5th in for warranty work so will see when p/u the unit. will post the results

 

[DGamelin]

I dealt with this when my truck was new, loaded only. I shimmed my shaft and didn't go away. I got a tape measure and found the shaft was not straight wound up slotting the holes moving the center support sideways and that fix it, no more shutter. If you go back in my post I had wrote about it when I did it with measurements.


_____________________________
2000, 2500, 2wd, XC, Auto, 354, 190k
04.5, 3500, 4wd, CC, Dully, 6-Speed, 373, 228k

 

[DGamelin]

I dealt with this when my truck was new, loaded only. I shimmed my shaft and didn't go away. I got a tape measure and found the shaft was not straight wound up slotting the holes moving the center support sideways and that fix it, no more shutter. If you go back in my post I had wrote about it when I did it with measurements.


_____________________________
2000, 2500, 2wd, XC, Auto, 354, 190k
04.5, 3500, 4wd, CC, Dully, 6-Speed, 373, 228k

 

[CFulton]

UPDATE
After 30+ days in dealer (2) shop trying to fix my problem---13 + different "fixes" (to include 3 new drive shaft assemblies, special custom shims etc.) regional rep out of Houston told dealer to tell me its "normal"! Yep took my 5th in for the experience. Dealer and I no agree so back to MO after engaging a Lemon Lawyer.
MO dealer got a rep out of KC to come and experience the severe shake. Before the ride he was very skeptical about the shake. I asked how far he wanted the ride--that 100ft would be enough--got the no believe look--100ft later asked him if that was enough. after a bit more, he was super impressed ---went back to KC to talk to the engineers. One week later got the letter from lawyer---Go pick out your new truck--they to replace!!!!!
Now awaiting the order, receive the new ride!!!!!!!!!!!!
They could not figure out the problem---said they had never experienced my "shake" as did both dealers. Both dealers really busted butt trying to get the fix!

 

[sag2]

Don't mean to rain on your parade, but what makes you think the new truck will be any different than the old truck? How much king pin weight are you running?

 

[jacknife]

I had LS when loaded with 5th wheel. Ram mech said it can be shimed but may do it empty. Put air bags on when loaded I inflate to fifty shudder is gone.

 

[CFulton]

Within lb limit re king pin weight and under total weights. am stepping up to the 3500 srw Aisin with the air suspension. Don't know but always felt the prob was in the 68RE. Dealers and reps wouldn't go there.

 

[Ozymandias]

A good decision anyway, the right truck for a heavy job.

 

[RustyJC]

Don't know but always felt the prob was in the 68RE. Dealers and reps wouldn't go there.

Nope, the 68RFE has nothing to do with launch shudder. We've used Ram duallies to pull heavy 5th wheels since 1996. My 1996 V10/47RE 3500 would launch shudder, as would my 2002 ETH/DEE (Cummins HO/6-speed manual) 3500, as would my current truck UNTIL I added rear airbags so I could level it back up, thus restoring the design pinion angle. I haven't had a launch shudder since adding the airbags.

Rusty

 

[sag2]

Nope, the 68RFE has nothing to do with launch shudder. We've used Ram duallies to pull heavy 5th wheels since 1996. My 1996 V10/47RE 3500 would launch shudder, as would my 2002 ETH/DEE (Cummins HO/6-speed manual) 3500, as would my current truck UNTIL I added rear airbags so I could level it back up, thus restoring the design pinion angle. I haven't had a launch shudder since adding the airbags.

Rusty

That is correct. Launch shudder is only angle related. That is why it happens when you load the rear of the truck. The reason you have a smooth ride is because the suspension is soft these days and travels quite a long ways. The longer the travel the harder it is to keep the drive line in the optimum range as you load the truck. The air suspension does a better job (within the weight limits of the system) by keeping the ride height in a narrow range. If they would have paid for a set of bags they would have also fixed it.

 

[CFulton]

Have the factory air suspension on my problem '14. Love the air suspension----keeps all on the level etc.

 

[CFulton]

Have did a poor job of describing the shudder/shake. Soooo
Truck rolling before applying throttle. Major low freq shake till about 30 MPH (things on dash actually bounce/jiggle around and your butt moves in the seat(s) then tapering to a higher freq shudder/shake disappearing at 4th gear. Not present when passing, downshifting on hills etc. Normal driving a minor annoyance. Makes no difference whether towing in the normal tow air suspension setting or the higher normal load setting other than the 5th being a bit nose high. Tow haul gives the same results.
All measurements within specs and same as other new trucks on their lots. Its kinda like something is seizing-release seizing release etc (slipping-grabbing?).
Oh well waiting and looking forward to my new ride.

 

[RustyJC]

What you describe is far from what I've experienced as launch shudder. Launch shudder (as its name implies) is a shuddering coming through the rear area of the truck that starts at/immediately after launch from a stop, decreases as speed increases and pretty much is over by 10 MPH. It isn't present at steady speeds or when accelerating from, say, 10 to 15 MPH or higher speeds.

Rusty

 

[NDanecker]

IMO, launch shudder is caused by an improperly aligned output (trans) and input (pinion) angles. The issue with 2 piece shafts is you shim them for what you think the angle will be attempting to keep both shafts parallel. When you load down the axle the angles change.

In a 2 joint setup (and properly setup i.e. both input and output angles are parallel) the acceleration and deceleration created by the joints rotating are cancelled out no matter if the truck is loaded or unloaded. If the angles are different you will 'bind' the shaft. With a center carrier bearing this binding will cause the shaft to shake side-to-side. This is the shudder and happens as the u-joints fight each other (out of sync for acceleration/deceleration).

Bottom-line - a two piece driveshaft will never work (unless you keep the first shaft parallel to the trans output which creates too step of an angle for the rear pinion joint) for every condition or alignment, and will change when you load the truck down. Shim it when empty and she'll bind when loaded. Shim it when heavy and she'll bind when empty. Its a loose-loose and a poor design.

I replaced my two piece shaft in my 04 with a single steel shaft and all my issues went away.

 

[TCDiesel]

I replaced both My 2003 and 05 with 1 piece DA Both kept the LS, when I replace the diffs (Both) with Tru-trac the LS disappeared , No BS. So the transmitting of power has some effect on the DL. MY 2013-14-15 all have 2 piece DAs none at present have LS.

 

[cerberusiam]

Truck rolling before applying throttle. Major low freq shake till about 30 MPH (things on dash actually bounce/jiggle around and your butt moves in the seat(s) then tapering to a higher freq shudder/shake disappearing at 4th gear.

That is not launch shudder, that is a driveline problem. Whether it is the trans or diff or the driveline itself is the mystery that is another persons problem now.

For the most part, launch shudder is really nothing but axle wrap and\or 2 piece DL deflection in high TQ conditions. As can be seen from the descriptions, it has nothing to do with ujoint angles. In the end, it is how rigid the drive line and suspension is under TQ that will determine the results. It will still happen with a 1 piece DL, when the truck is level or raked, etc.

 

[HorseMan-AR]

Just bumping an older thread, but my new 2015 3500 SRW with OEM rear adjustable air ride is experiencing what I call this launch shudder. It only does it when loaded with fiver (11-12K pounds). Fiver is well within tow/payload capacity of truck. Usually only feel shudder when loaded AND going up an incline - at low speeds. Only does it when upshifting from 2nd to 3rd - almost like truck shifts into 3rd with RPMs being too low. I can manually shift to 2nd and immediately, the shudder disappears. Crew cab with one piece drive shaft, AISIN, 4x4, 3.42 rear axle.

I have all the latest transmission flashes and truck as 3400 miles on her. Any comments?

 

[Newsa]

Just bumping an older thread, but my new 2015 3500 SRW with OEM rear adjustable air ride is experiencing what I call this launch shudder. It only does it when loaded with fiver (11-12K pounds). Fiver is well within tow/payload capacity of truck. Usually only feel shudder when loaded AND going up an incline - at low speeds. Only does it when upshifting from 2nd to 3rd - almost like truck shifts into 3rd with RPMs being too low. I can manually shift to 2nd and immediately, the shudder disappears. Crew cab with one piece drive shaft, AISIN, 4x4, 3.42 rear axle.

I have all the latest transmission flashes and truck as 3400 miles on her. Any comments?

I think pg 7 of this thread might explain? The Aisin might not know its lugging the engine?


https://www.turbodieselregister.com/threads/251817-2015-auto-or-manual-trans/page7

Just a guess.

 

[Cummins12V98]

Just bumping an older thread, but my new 2015 3500 SRW with OEM rear adjustable air ride is experiencing what I call this launch shudder. It only does it when loaded with fiver (11-12K pounds). Fiver is well within tow/payload capacity of truck. Usually only feel shudder when loaded AND going up an incline - at low speeds. Only does it when upshifting from 2nd to 3rd - almost like truck shifts into 3rd with RPMs being too low. I can manually shift to 2nd and immediately, the shudder disappears. Crew cab with one piece drive shaft, AISIN, 4x4, 3.42 rear axle.

I have all the latest transmission flashes and truck as 3400 miles on her. Any comments?

Are you in tow haul when this happens?

 

[HorseMan-AR]

Are you in tow haul when this happens?

I've tried both ways, actually.