Drive train clunk

[BKW]

Originally Posted by SKEET

Mine is fine from a dead stop only when coasting and then getting back on the gas.I guess its axle wrap what ever that is, Ive heard alot about it on this site and seems to be common and seems to be the problem with the thump when touching the gas after coasting.

Axle wrap has been common on GMC/Chevvies for years....

Play in your driveline is the cause, I'm guessin'...when you get on it, driveshaft slaps a bit before engaging.

[XRING600]

Originally Posted by BKW

Axle wrap has been common on GMC/Chevvies for years....

Play in your driveline is the cause, I'm guessin'...when you get on it, driveshaft slaps a bit before engaging.

I believe this is what is causing much of the "clunk" in our trucks. Crawl under your vehicle, wrap your hands around the shaft(that is the ONLY time I will say that!), and move it back and forth. I can do this and produce a "clunk" in my 06'. Now, put some torque behind that play and I am sure that is the cause of some of our noise.

[SKEET]

Originally Posted by JetTech

ok all, let me see if I can explain this without confusing myself and everyone else. I'll attach a few photos and give a brief description of each one and then try to summarize it the best I can so here it goes.

The pic below is a depiction of an axle mounted below the leaf springs (like on the Titan) in a static condition.



This is a picture of what happens to the leaf spring during acceleration more commonly known as axle wind-up, or axle wrap. The nose of the vehicle would be to the right of the picture to help you visualize what's happening.



Many manufacturers have this same problem, common cures are traction bars or ladder bars for off roaders and racers. Usually it's not as noticeable as it is in the Titan, Nissan should have used either thicker main springs or a multi-link suspension to help cure this but I'm sure cost was the biggest factor.

Here's a few pics of what I installed to eliminate this problem





Here you can see how they are just barely visible from the side



What your looking at are $22 helper springs I bought from Advance Auto Parts. I installed them in front of the axle instead of the rear like most would do. During acceleration this big beefy spring will transmit the twisting motion of the axle to the front of the spring where the attach bushing is. I've had these installed for several months now and will never take them off, that's how much I like them. They eliminated all the clunking noises I would hear from the axle twisting up and down during acceleration and when I came to a stop.

Another benefit I've noticed is they really work like traction bars because I can barely spin my tires now at take-off, but it feels like the front end is going to come off the ground. It transmits all but a few percent of the torque directly into the chassis rather than leaving it on the ground in the form of burnt tires.

The Nissan Tech took some photos of what I did and sent them to their engineering department in California. He loves the fix but agrees that Nissan will never approve such an item for axle wind-up and that it will probably take eons before the issue is seriously looked at. So that's it in a nutshell. It fixes all the clunking for $22 and doesn't negatively effect the ride at all. As a matter of fact I can really feel a positive difference in corners, the truck stays much flatter and feels much more solid when the corners get bumpy.

I would love to stick around and see what you all think but it's night night time for me......4:30am comes early and I've still got a heck of a honey-do list. I'll check back in tomorrow night and try to answer any questions you all might have.

Dale

For what ever reason my computer won't let me see the pictures but I remember looking at them a while back so I do have a idea how the install looked.I've had the springs for a while and started to put them on a few minutes ago but I have a question.I see that the end with the big U bolt presses the springs together but I don't see the purpose of the other end with the bolt just coming end from the side.I know I'm missing something but why not just put a u bolt on the spring and call it good.Thanks.

[sudden urge]

Originally Posted by SKEET

For what ever reason my computer won't let me see the pictures but I remember looking at them a while back so I do have a idea how the install looked.I've had the springs for a while and started to put them on a few minutes ago but I have a question.I see that the end with the big U bolt presses the springs together but I don't see the purpose of the other end with the bolt just coming end from the side.I know I'm missing something but why not just put a u bolt on the spring and call it good.Thanks.

Good observation, you can just put on a U bolt and get the same preload effect. I discussed that same question with a spring shop a long time ago, and they said you will get the same result. I went with the Hellwigs because they don't compress the spring and lower the rear.

[SKEET]

Originally Posted by sudden urge

Good observation, you can just put on a U bolt and get the same preload effect. I discussed that same question with a spring shop a long time ago, and they said you will get the same result. I went with the Hellwigs because they don't compress the spring and lower the rear.

I'll check out the Hellwigs.I remember a while back you said you had put them on your truck and hadn't had any problem with them coming loose are anything like that.

[sudden urge]

Originally Posted by SKEET

I'll check out the Hellwigs.I remember a while back you said you had put them on your truck and hadn't had any problem with them coming loose are anything like that.

That's correct.

[SKEET]

Originally Posted by JetTech

No I didn't. I think it's got plenty of spring tension without them....here's a couple of pics that better show the mounting of them..

Is it just me that can't see these pics any more or have they been removed?

[StuntDriver06]

just an update on my situation... the clunk in my drivetrain was a failing diff, its at the dealer being replaced right now, along with the driveshaft

[StuntDriver06]

rear end replaced, clunk completely gone, this feels like a different truck now, amazing difference. no more slop.. when i touch the go pedal, it goes instantly...