WEIMWGN

I've got a 2010 JKU with an automatic transmission. The other day I was on my way home and I noticed a slight clunk sound when I take off from a dead start. I cant feel anything in the steering but I can feel it in my shifter. When I got home I crawled under my rig and checked the suspension and drive lines. Everything seems to be normal. I do have a transmission temperature gauge and everything looks normal there too. Any ideas?
Thanks in advance for any help!

resharp001

Are you insinuating it has something to do with the transmission or shifter? Is the sound only from a dead stop moving forward? Every time? What about from a dead stop to reverse? Suspension components can "look" ok, but you'd be surprised how something under torqued by 10ft lbs or so can start to make a noise. Under torqued control arm bolts can start to make a clunk when the weight of the jeep shifts from forwards to backwards, or vice versa....like braking in to a stop, and then accelerating from the stop. That said, I don't think you'd be feeling that in the shifter. If it were me, I'd double check torque on all suspension bolts, and then continue trying to narrow down various circumstances under which the clunk does or does not present itself. If it's something you can replicate often, I'd put someone else in the jeep and you listen from outside. I've gone so far as to carefully lie under the jeep as someone drove back and forth over me to pinpoint a DS issue. Gotta be careful to watch your head with the front diff and your nads with the rear diff....LOL

jeepmojo

sounds like drive shaft u joint if its a thud each time you let off. And then accelerate or from a dead stop eventually they will chirp like a bird before they shear off / dont wait that long once you hear a chirping !
as you know the stock drive shafts you cant replace the u joint which i thought was foolish . buy a whole drive shaft at 800 .00 cuz the 14.00 u joint failed lol

jkrubcon

Check all sway bar bolts

WEIMWGN

The sound is only when you start from a dead stop and not in reverse.
I will definitely get under with a torque wrench and pry bar and do a closer inspection.

Rednroll

You can't replace the stock front drive shaft U joints?

resharp001

Under torqued sway bar bolts will definitely make a noise, but not on a flat surface with forward and backward movements. They will make a noise when the body rolls or the axle gets off camber, like turning to go up an incline, or just grabbing the rear body and shaking it back and forth with your hand.

In regards to DS.....just as good a chance as anything else really, but typically you'd get a lot more noise than a single clunk from a start as that shaft is turning around a lot.....and from my experience, DS noises tend to get worse quickly, so pay attention for any changes in the noise.

The one thing that stood out from your original post that you don't normally see people describing, is feeling it in your gear shifter. It sounds like you can reproduce it, which should make tracking it down a bit easier.

jeepmojo

The whole drive shaft has to be replaced / that is just dumb / my front was replaced early on under warranty but no they are made so you cant replace the u joints , and at those prices its cheaper to buy aftermarket

resharp001

Technically, you can....or there are people that have, but it's really not worth the effort. You have to mill out the pressed tabs that crimp the u-joint in place (the factory doesn't have simple retainer clips). Then when reinstalling, you'd have to mill out a grove for a retaining clip. LOL. I mean, y, it's not worth the effort, but you COULD if you REALLY wanted to. Easier to just find a take off on CL for $50-$100, or better yet, just replace with aftermarket.

lateralus

I have a similar noise coming from the left rear wheel area. It seems to do it when turning from takeoff especially but not everytime. Sounds similar to when I park on a hill and engage the e brake and let off the foot brake and it makes a clunk as it rests into place. Thinking it could be a bad brake pad or something?