Noise disappears in neutral

[matthop53]

I have been chasing a noise ever since I put on my suspension lift. The truck will make an intermittent noise when I am coasting above 40-45 mph. I thought it might have been the drivers side cv so I changed it and the hub assembly and I have had both drive shafts lengthened because they were coming out of the transfer case. The noise will stop if I shift into neutral or when I accelerate. Any help would be great.

 

[noJeepshere]

How big a lift? and did you put some good Spicer u-joints in? I know when I lifted mine that the u-joints didn't like it and would creak on acceleration. That could be your problem.

Do you have more pics of your truck, btw? From what I see it looks really cool.

 

[matthop53]

I put on a six inch lift. The u joints are fine the guy that built my new drive shafts said they looked good. The noise happens when I coast not under acceleration. I haven't taken any recent pictures it's dirty but I might this weekend it looks like its going to stop raining for awhile.

 

[bowtiefreak]

did you swap gears? How is the back lifted? Is the pinion angle correct?

U joints could be bad regardless. Had both mine fail shortly after the lift due to the increased angles on them and their age.

 

[JenneK]

So what does this noise sound like?

 

[matthop53]

It has the stock 3.73 gears, pinion angle was adjusted by the guy that fabricated the rear drive shaft, the rear is lifted by a 3in block 2in add-a-leaf. Tire size is 305/70 16.

The noise is an intermittent low frequency whan whan noise(sorry I can make the sound better than describe it) It's definitely not a grinding noise and it isn't consistent and the noise can be drawn out or it's a short bust

 

[matthop53]

It could be the u joints but I just had the drive shafts done and he said they were fine. He suggested it was the possibly the pinion bearing, but wasn't sure, I was hoping to get some independent verification from somebody.

I am thinking about putting in a 14 bolt before the 10 bolt gives up the ghost anyway, but I feel like one thing keeps leading to another and I just want to enjoy my truck.

 

[bowtiefreak]

could be the rear, your right. U joints isn't a big deal to do, how old are the ones on there now?

Does it feel like a vibration? I had trouble chasing a driveline vibration right after my lift on my two door. Drove me nuts, got worse after I lifted the rear a little taller too. All came down to the U joint angles on the driveshaft.

If by some chance it is, this really helped me a lot.

http://www.4crawler.com/4x4/CheapTricks/Driveline-101.shtml

 

[matthop53]

There is a slight vibration, but not soo bad that if you are not looking for it you wouldn't notice it. It drives down the highway no problem. Thanks for the link I just glanced through it... very good info

 

[Donnie Yukonie]

I bet its the u joints mine went out and i just lifted as well

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