Launch Shudder when towing

[CFulton]

2012 2500 4wd long bed 7600 total miles 4200+ towing 14,000 lb 5th have the OEM air suspension.

From the get go have had minor to severe shudder on launching---if launch super easy not so much but routine launch (not real heavy foot) shudder is there and irritating as he--. Dealer said he did the shimming, but got worse, on occasion entire truck severe shaking! Occurs 2-3 mph to shift point in varying severity. easing towards the shift point.
Took in back in Dealer "couldn't find anything wrong, said checked u-joints etc., and all OK and just drive it".
Any suggestions? Only there when pulling the 5th.

PS my 03 had it and shimming fixed my '12 had the same problem, shimming helped some but not all. Now the '14 which is worse.
Thanks

 

[GCroyle]

Auto trans or manual trans?

 

[TCDiesel]

Both My 13 & 14 have some launch Shudder, MY 2003 and 2005 had it also. the only fix for the shudder was Trutrax and New pinion and side bearings, I also changed the TQ specs to 110FT LBS and went to .04 additional shim on the pinion shaft and .04 on the backlash. Have the dealer check the Dif spec's. I now that shudder is bothersome but I have never been able to detect additional wear form it, that's a good thing.

 

[CFulton]

Automatic love the truck otherwise

Had to replace the pinion seal on the '12 at about 50,000 shudder was bothersome but not near like my '14 now

Will see dealer with T&C Diesel fix

 

[sag2]

Launch shudder has nothing to do with gear set up. It is angle related only. If it shudders loaded reduce the height of the center support. There is an old TSB with the different size center supports. There are 52105714AB, 52105715AB, 52105717AB and 52853310AA listed as possible PN's that fit a single rear wheel 2012 2500. The TSB is old but it still applies to late model trucks. If you list the last six of your VIN I can tell you what PN your truck currently has. You can also measure it and check it against the TSB dimensions. Also be aware that if you fix it loaded, it may shudder unloaded.

See the TSB attached.

View attachment Driveline Launch Shudder TSB.pdf

 

[TCDiesel]

I will explain my experience with launch shudder over the last 2.5 Decades. generally when pulling and towing with AAM axles, I have never experience the shudder on any Dana axle and /Chrysler combo, Ford or Ford Dana combo, its rare on the GM AAM combo., many owners went to the 1 Piece DL without the hanger only to discover the LS was still there, this includes ME, it did NOT disappear until I installed the Eaton Trutrac, The Trutrac divides the ground power much better then the AAM axles, Its how the power divided in The tructrac to lessen the DL stress, After I change the Diff it never shudder again load unloaded., I had many customers buy the Trutrac and will make the same claim, So Ram can go pound sand on this one.

The LS will disappear for a time in the Ram/AAM combo ,but after you tow heavy for some time (HWY Speeds 25 miles or more) it will reappear on the get off ramp when turning sharp right or left. Again I need to state I have NEVER seen unusual wear or breakage form LS. So I would just ignore it unless its all the time and shudders *********

On edit: https://www.youtube.com/watch?v=lZmsY2YvVsc&feature=player_detailpage

 

[sag2]

I think you are confusing launch shudder with shudder on turns. Launch shudder is straight line vibration only up to about 10mph. It is only from drive line/pinion angle and will occur with open or limited slip differential. The fact that it does it loaded vs. unloaded proves it is angle.

 

[GCroyle]

Guys,

Just an inquiry from left field.

Does the air suspension contribute to LS?

It carries weight, but does it control axle twist?

Please, I've never seen the setup, its just a question not claiming any first hand experience with it.

 

[Gonzo 1066]

Launch shudder is caused by a change in driveshaft-universal joint angle. As you accelerate the truck with a large load the rear axle will tend to pivot the pinion shaft upward, thus changing universal joint angle and causing shudder. Often called spring wrap. This is the reason that LOTS of drag cars go to a 4 or 5 link rear suspension as the linked suspension maintains the optimum driveline angle. I used to have shudder issues with my manual 6 speed 04 hotrod Dodge towing heavy, After I installed a Kelderman air ride suspension on the rear (a 5 link setup) my launch shudder went away.

 

[cerberusiam]

The launch shudder on straight line accelration is just the result of the NVH built into the spring packs, it is axle wrap and release for the most part. Only way to cure that is stiffen the front part of the spring pack to minimize it, or, add a traction bar to control it.

The shudder on a turn is like TC said, its the TQ bias LS getting grabby. Sometimes the wrong fluid is used and that will make all the difference. Surprisingly, many people add limited slip additive to alleviate this problem on the advice of dealer or repair shop. It works, but, that is not neccessarily good for the LS.

 

[sag2]

Technically with air suspension the ride height should be the same loaded or unloaded, but it must not be holding the same height. I don't think the axle would wrap much more either way except you have more torque trying to lift the pinion.

 

[Kry226]

Really think this is a non-issue for most. My 04 does it and only when towing or loaded heavy, but my wife wouldn't even have noticed it if you asked her.

The biggest thing that gets me is that it is wasted power not being put to the ground. But it's not worth the effort or expense to correct unless it's truly a BAD problem and is making drive quality suffer.

 

[sag2]

I would agree based on the circumstances. I tell customers if it only happens loaded and you drive loaded 20% of the time just ignore it. But if you are loaded 80% of the time fix it, but you may then shudder unloaded. There is a very fine line to getting it to stop at both extremes.

 

[TCDiesel]

Sag2, Have you ever seen unusual wear form it, Many owners believe that this will cause premature failure of DL component's.

 

[AH64ID]

2014 2500's use a 5 link, there is no axle wrap. Ride height should be the same loaded or unloaded.

Is there a carrier bearing on your truck?

 

[AEdelheit]

The way the 5 link is designed with how high on the axle the lower arm is mounted and the giant rubber bushings they actually do get some axle wrap and wheel hop in the right conditions.

 

[AH64ID]

The way the 5 link is designed with how high on the axle the lower arm is mounted and the giant rubber bushings they actually do get some axle wrap and wheel hop in the right conditions.

It's not going to be much.

 

[AEdelheit]

No its not as bad as leaf springs but there is a little bit. For some reason the lower arm is mounted above the center point of the axle, if they moved it down 4" or so it would have much better control.

 

[jacknife]

My 14 3500 has launch shudder also when loaded and just starting off. Never empty.Am taking to dealer when l get home. Never had it with my06 3500 towing same trl. Will also show him some of your posts reguarding this problem. The info was invalueable, espcially when the dealer tries to shine it off.

 

[Tuesdak]

I suggest you put a camera under the truck pointed at the propshaft (rear driveshaft) and include the center support bearing in the view. Make a recording during the Launch Shudder. Even better if you do a brake stand and can get it to shudder without the rear wheels turning.

Edit: when going to the dealer you need to take the "load" with you as weight changes the driveline angles, but, most importantly puts a load on the drive line to get all the weight moving making the Launch Shudder more noticeable.

On both a Duramax and a 22 year old 6.5TD I have had this issue. Granted a Highly Modified 6.5... To solve the Launch Shudder on the 2500 6.5 I used a poly center bearing. We were watching the Prop Shaft jump up and down about 2" in the soft center bearing. After adding the poly center bearing I get a vibration at 75 MPH. (Trade off?) Being as trailer tires are speed rated to 65 MPH this isn't a big issue. (Sad when you finally have the power on a 6.5TD to tow over 65 MPH and can't... :-laf ) Perhaps other changes could eliminate the 75MPH vibration - it's bad enough to not want to go over 75. The prop shaft was checked, balanced, straightened at a shop that all they do is prop shafts. Not cheap and I do have a balanced and straight one now with a lighter wallet. Did not stop the high speed vibration that the "soft" rubber center bearing appears to take care of.

YMMV

Poly center bearings available here and more drive line info like the PDF file listed above:
http://www.iedls.com/Center-Support-Bearings/Pickup-Trucks.asp