sporadic clunk up front when shifting and going over bumps

2011 manual 6 speed, if i don't let the clutch out very slowly, i hear a medium-pitched clunk sorta near the floorboard or trans tunnel up front. the sound also shows up when going over certain types of terrain. it's not high pitched, it's not a low tone thud, but it's definitely noticeable. it's not related to the clutch since it is induced sometimes solely via the terrain, like a clunky torque mount or something. it sounds like a tiny door being slammed or like something is loose. it might have been doing it all along but i never drive without the radio on.

 

bump for thoughts

 

I have no idea. But I found that if I am moving in first but not really accelerating and push the clutch to shift, that induces quite the clunk. Sounds normal but its not a good sound.

I also have a certain random clunk that happens when I back up. I cant create it though, its random.

 

Mine does the same thing.....its just the drivetrain unloading when the clutch is pushed in. Only does it in first. I feel the 1st gear is way to low for every day driving. Ive heard and I figure 1st will mellow out a bit once I get my lift and 33's installed. To the OP, I guess get under the truck and have a look for anything obviouse. Or since its a 2011 take it in and see if a tech will go out with you so you can reproduce the noise. I dont seem to have the same noise you do, mine is just clutch+1st gear. Does everything else feel ok? Have you tried to set the E-brake hard and then put it in 1st and kinda let out the clutch a bit just before you stall it to see if it will happen when loading the drive train? A lot of times this will reveal a broken mount somewhere. Dont let out the clutch hard cause this can brake a mount.....just enough to load it and then unload it. IDK maybe this will help you figure something out.

 

thanks for the responses. so i could see every crevice and detail, i looked hard under the truck in my garage with a flashlight. everything looks ideal the broad lower trans mount looks solid as heck, the one with the blocky rubber isolators. the two lower engine mounts are also perfect. there is no evidence anywhere of any banging or contact. all suspension bolts and attachments look fine; factory check marks are still intact. my truck looks like a new truck underneath, lol.

i am going to drive in 4wd a bit tomorrow and see if that changes anything, as it would put tension on the front shaft. also, i am going to try the suggestion of loading up the drivetrain a bit with the e-brake on, but it really doesn't seem like a drivetrain issue to me since it happens when the truck sees certain mild bumps; best i can explain is the type like when the top layer of the road is missing in a patch and has abrupt edges. slower vehicle speeds as opposed to mid-high speeds.

it's really easy to reproduce. i'll probably take it in even though i can't hear it with the radio on and i always drive with the radio on. maybe it is supposed to sound like this and nobody is noticing it. i have a bothersome attention to detail so that might be to blame as well.

 

anddd...it doesn't do it when i load up the drivetrain with the e-brake on.

 

Hey man I have the same exact "bothersome attention to detail" I work on aircraft so this is a good thing. Its called CLSA (Cant Leave Shit Alone) Sucks dont it!

Anyway are you sure this sound isnt a loose spare tire? Also I was thinking about it today and I have another noise that is exactly what you describe.....it would be the exhaust. When I hit a rough patch of road as you describe ....like an abrupt edge or pothole.....I hear my exhaust bang. Its somewhere on one of the hangers but Ive been under my truck several times and havent found a thing. Honestly if it is your exhaust doing it like mine does.....theres not much you can do but live with it. I know, I know it shouldnt do it but...it does and it sounds like ass! Ive learned over the years how to control CLSA a bit so Im ok with the sound.....probably more because there really isnt much I can do about it. If it bothers you that much you could take it in to a shop and tell them to add some more support to the exhaust....like a couple more hangers in different spots. Just remember though.....exhaust needs a little room to budge from the torque twist of the engine. If you make it to ridgid it will develop leaks quick! Hope this helps....post up if you figure something out.

Shawn

 

haha, thanks! yeah i'm fine with it if it's normal, meaning nothing out of spec. that is where my own CLSA symptoms die down. it's weird - i posted the other day, before post #7, about when i tried it in 4WD but for some reason the post didn't stick. anyway, i put it in 4WD and drove around, and it doesn't make the sound, at least the one from shifting. not at all. and i couldn't get it to make it when driving over strange abrupt bumps and stuff either.

i almost am wondering if it's that front shaft going to the front diff from the transfer case? when i shift or go over bumps, maybe that front driveshaft being "free" makes the sounds as it jiggles back and forth. naturally in 4WD it is under tension, so it won't do that, but in 2WD it's free as a bird and loose. when i have some time to kill i'll probably go drive another on the lot to see if it does the same thing.

 

i get the same clunk in first just like you described it iv got an 08 access cab 4x4. I Plan on draining all my driveline fluids this weekend to check for anything.