I have a new 3500 crew cab dually with 2500 miles on it. When I start from a dead stop there is a thud or bump feeling that seems to be comming from the driveline somewhere, now it has started doing it just before I come to a stop also. Any help? Is this normal?

Check your lug nuts?

As soon as you start out or about the time the tranny shifts? Sound coming from the back, or under the floorboards?

Have checked lug nuts. You can actually feel the thud just as you take your foot off the brake or just before you come to a full stop. I suspect u-joints, or a loose tranny mount, thats what it feels like.

Not the driveline per se.

Something suspension wise is loading up when you brake and releasing when you let off the brake. I would bet if you go down hill and come to a stop out of gear, then let off the brake you will hear the same noise.

That sort of sound has always been related to the front A arms for me, but I do know others that have had rear spring bushings, U-bolts and/or wheel bearings loose and heard a similar sound.

One other possibility that I have heard of but never seen. You said you have a 3500. I assume it has the helper springs. If you are loaded up, but not enough for the springs to make good contact, you might be hearing the helpers slap the supports.

Trannys, u-joints and such will make rythmic noises in proportion with speed or thunk when going into/outof gear.

my 2500hd did the same truck didn't roll 5 feet and thud. greased the center slip joint in driveshaft and the truck is as smooth as my wife's buick

That would be my bet too. Sounds like a slip joint binding in driveshaft. THey do not grease them well for factory. Use a moly based chassis grease (a black grease) and it will last a lot longer between lubes in that use.

I wonder if his even has the intermediate shaft. Mine is a solid shaft all the way from Tranny to rear axle.

I wonder if his even has the intermediate shaft. Mine is a solid shaft all the way from Tranny to rear axle.


Easy to find out anyway. I have seen slip yokes in trannies and bind like this too sometimes.

rfcb, any closer to finding the thud? Enquirering mind want to know.http://www.dieselplace.com/forum/smileys/Big Smile.gif

The dealer knew exactly what the thud was and was able to "duplicate the problem", greased the splines on the driveshaft and the thud is gone.


Thanks for the help.

After reading this, I went and did mine today...was able to reuse the clamp on the rubber boot. Greased the splines on the center splines and splines going into the transfer case. Night and day difference! I wonder how often it should be done. Maybe they should have placed zerks on the yokes.

Can anyone give instructions how to grease the splines?

Pull the driveshaft out and also unbolt the center carrier bearing (2 piece driveshaft)from the frame. Carefully undo the front clamp holding the boot on (2 piece driveshaft). scribe a mark on the 2 opposing shafts for location (clocking of u-joints) pull apart and smear grease on the splines inside and outside. re-align the scribs and put the splined shafts back together. squeeze the clamp tight (you can buy the clamp squeezer at any auto part store). Put some grease on the inside splines of the front yoke and reinstall just like removal....http://www.dieselplace.com/forum/smileys/Cool.gif


Does that make sense?

KTDUAMAX-


Makes sense! Thanks!

You can just take the rear u-joint loose, remove the clamp and slide the rear half of the shaft out. You do NOT have to take the center bearing down.

Can anyone post pictures???? Sorry, sounds simple but pics would really help.

I have the same issue and the dealer takes care of it each time. I have yet to pay for it......Push them a bit to do this as it is cleary an issue on their part. As another member stated before they don't grease them worth a @#$@#$. Would be nice if they would come up with a zerk fitting on the yoke to fix that.
:grd: