6 speed noise

[BIG C]

I have a loud noise coming from what I have determined to be my NV5600. It shifts fine, runs smooth but makes a noise possibly a vibration when cruising down the road. Kind of hard to tell with the 5" exhaust.



With the trans in nuetral and the truck stopped there is no noise, even if I change RPMs. However with the truck moving and I put the truck in nuetral the noise is still there. Certain bumps going down the road will magnify the noise even more. Now the weird part, if I steer the truck from straight ahead or to the left there is no noise... ... however if I turn the wheel even slightly to the right the noise is there for the entire time until I straighten out the wheel. This happens at diffrent speeds and at diffrent RPM's. I thought maybe the steering pump..... but there is no noise if the truck is not moving. Any thoughts???? This is a used stock NV5600 and clutch.



I think it sounds like a bearing but why does it go away if I turn to the left??



Thanks,

Chad

 

[Hoefler]

It is going to be behind the transmission. Slip the transfer case into neutral and see if it goes away. If not it will be in the driveline or rear diff. If you do not have lock outs on the front axle, it could be up there.

 

[BIG C]

Why do you think its behind the transmission?? Could be. Although it sounds like its coming from up front like in front or under the dashboard. I dont have the front driveshaft hooked up right now so that cant be it. Doesnt feel like a drivetrain vibration you would get from a driveshaft. Maybe its resonating up through the transmission and sounds like its up front?? That might make sense because with the transmission in neutral coasting down the road the noise is still there especially if I turn the wheels to the right. Any other thoughts??

 

[formula]

hummm... ... . sounds like perhaps the left front or left rear wheel bearing. Also may be a front axle shaft ujoint or spindle bearing. If you've got manual hubs, unlock them and see if the noise goes away. Try putting the truck up on stands and spinning each wheel by hand (with engine off) to have a listen to the bearings. And while you're poking around anyway, have a look at the brake rotors to see if they're gouged up at all.



Sean

 

[Hoefler]

With the truck in neutral sitting still, clutch engaged and engine running, everything in the transmission is spinning except the main-shaft and the output bearing. If the noise was in the transmission, you would hear it. The drive shaft does a wonderful job transmitting noises to the cab. With it happening when you turn one way and not the other, would lean towards the front axle. It possibly could be a rear wheel bearing since you change the side load when turning.

 

[BIG C]

Did some more testing, when power is put through the transmission the noise is the loudest. A loud sewing machine noise (bearing?) between the shifter and the motor, right under the dash. Again if I turn the wheel left nothing, just slightly to the right and the noise is there. If I let off the gas but keep it in gear the noise is still there but MUCH quieter. Get on the gas again and its loud. The front end is totally disconnected from the Tcase, no driveshaft hooked up. I will try the sitting in the driveway test with the transmission in neutral with the clutch engage and disengaged. I cant remember what I did last time. Thanks for the help.



Chad

 

[BIG C]

More testing... . it seems the noise is consistent with RPMs. The more RPMs the louder the noise. Coasting down the road at 55 and idle the noise is very feint and harldy noticable. If I increase the RPM's but still coasting the noise is MUCH louder. I am thinking it might be the 5" exhaust resonating on the transmission or frame rail. It is very tight in there and when turning right it might shift everything just enough to create the noise. I still havent been able to hear the noise when sitting still in the driveway at idle or even at higher RPMs. Its mostly when moving and at higher RPM's. Any other thoughts???



Chad

 

[nickleinonen]

could be the exhaust touching something. . take a close look and see if it has any rub marks anywhere [if you can slide your hand between any close spots, there should be enough clearance]



i still wouldn't count out a bad u-joint. they only really act up under load until they get really bad, and the sound travels around making it sound like something else could be causing it [i had 2 bad rear joints that were sounding like the the noise was coming from the front/right corner until they seized up and vibrated the heck out of the truck]

 

[BIG C]

more testing... turns out that with the truck not moving in the driveway and at higher RPMs the noise is there. Only at higher RPM though. So this rules out any drivetrain issues. I am leaning towards the exhaust resonating on the transmission or frame rail. With the 5" pipe coming down off the 4" DP its really tight in there. I plan on installing a new clutch in the near future so I will try and do more testing with the exhaust removed. Thanks for all the help.



Chad

 

[Hercules130]

Throw-out bearing?

 

[BIG C]

Thought about that... . I did put a new one less than 5K miles ago. The noise does not change whether I push the clutch in or let it out when in neutral. Not sure if this would matter.