Gearbox Noise

[AustinK]

In my 74 series III I have the 4speed gearbox and transfer case with a roverdrive overdrive unit. It recently started a high pitched chirping when in gear. anyone have experience with this type of noise? bearing??? all three units were rebuilt/replaced in the last 5 years. Thanks
AK

[I Leak Oil]

It's very tough to diagnose drivetrain noises via the internet. First thing I'd look at is your parking brake and U-joints though.

Does it do it in all gears? If you push in the clutch while moving does it still do it? What end of the gearbox do you think it's coming from? Any grinding or other symptoms?

[SafeAirOne]

Are you certain it's driveline-related? Every time I hear a chirping under load I panic and think my transmission/transfer case is even WORSE than it already is, only to realize that the noise is coming from a failing or loose alternator.

[AustinK]

With the clutch in and the vehicle stopped it doesn't make any noise. If I put the transfer case in neutral and the gearbox in any gear and release the clutch the chirping is present. If I am rolling and put in the clutch the chirping stops. It also stops briefly when I let off the gas. It sounds like it is coming from the gearbox but had to know until I can get some one to run it for me while I listen under the truck.

[bugeye88]

I had a "chirping" squeak coming from the gear box area awhile back that was irritating more than anything else. I finally took off some of the floor board pieces to be able to see and use an automotive stethoscope on the tranny. I traced it down to some external fixings of the overdrive and with a little WD 40 got it silenced. So I would pull some of the floor tin and trace it down.

[I Leak Oil]

So is it fair to say it only chirps with the motor running and the clutch engaged? You don't notice the clutch slipping or hard shifting issues? I'd say put the x-fercase in neutral, put it in gear, let up on the clutch and get someone to pinpoint exactly where the chirping is coming from.