Need help determining weird clunking noies

Hey all I've looked on here and haven't found a definite answer. I have an 04 D-cab with v-6 and autos tranny. I am getting a clunking sound coming from the tranny forward. I haven't been able to pin point exactly where it is coming from. It clunks when I am in 2WD and I let off the gas, then give it more to go. It will do this between 15 and 40 MPH. Funny thing is when I slow down and come to a stop, it will do it as the truck slows down between 5 and 10 MPH. If I put it in 4WD, I don't notice the Taco making the noise. It is almost as if it is locking in a 3 gear then shifting to 2nd to take off and locking in 3 then suddenly releasing to 2nd when slowing down. The Taco runs and drives fine. Anybody ever experienced anything similar?

Thanks

 

So it doesn't have any trouble shifting? Middle of the truck? More to one side or the other? Could be the CV axles starting to go or a U-joint along the driveline. You can check both of those possibilities by grabbing the CV/u-joint and checking for play/wobble there. I would start by getting under there and wiggling just about everything you can get any purchase on. If you find anything loose, it's probably that. If not, maybe your tranny is doomed

There's a lot of threads on CV's and driveline vibration. Good luck.

 

My guess would be U-joints. Changes in torque in the driveline when changing gears will cause this when the joints are worn or underlubed. I dont know if 1st gens have grease fittings on the joints or not, but if they do id try lubing first. My 07 had this problem but has aftermarket joints with grease fittings.

 

Well, I finally got around to checking everything out while I had the back axle off the ground. My u-joints were replaced not too long ago, and I keep the entire driveline greased pretty well. I have a little play all the way into the tranny, but I think that is normal. What I did see was play in the slip joint on the back driveshaft. I was rocking the rear wheels, holding the driveshaft steady towards the double cardan joint, and watching the slip joint. I can see the male part at the back axle move slightly before the female part begins to move. It will stick and pop as everthing mates up in order. What I hear in the cab is the popping noise resonating through the hollow part of the driveshaft. Outside of replacing the drive shaft, or having the part with the slip joint replaced, I don't think there is much I can do. I don't think it is hurting anything, and won't unilt it fails entirely, but it could run as is till the Taco falls apart entirely.

Has anyone ever seen play in the slip joint like this?

 

It needs play for the axle movement, check your LCA bolts and torque them to specs. I had a pop/clunk at low mph and torqued my LCA bolts to 88 ft lbs (what the specs require for 2nd gens) and they went away completely.

 

I think what he is saying is it has rotational play. In and out yes I agree is needed for suspension flex and axle movement. Should be very little rotational play.

 

Gotcha, I mis read where he says he was rocking the wheels holding the shaft near the joint.

 

Mine did the same and the sway bar was loose at the end-links.

 

Might be axle wrap. I had a clunk at low speeds when accelerating. Took me a while to diagnose it because I could only hear it in the cab. AAL's took care of it. OP are your rear leafs worn out at all?

 

I replaced them about a year ago with the Alcan 5-leaf packs.

When I was under the truck the other night, I actually reproduced the noise by rocking the tires while the axle was off the ground. I could see the movement in the slip joint. It would move slightly before the rest of the drive shaft. It would pop just about the time the rest of the drive shaft started twisting.