Loud clunk from driveshaft

[Jaymitch]

Getting a very loud clunk and vibration coming from what seems to be the front driveshaft in my 90 K5 Jimmy. Just started today with no prior warning. Happens in 2wd. Extremely loud and increase in sound while driving. I can turn the front driveshaft by hand and can hear a clunk from the left wheel. Am I right in guessing this is a bad hub?

 

[Justin V]

I'm totally confused.

Front driveshaft and hub are not the same thing.

Hub consists of several pieces. Outer selectable hub or auto hub or drive slug, then wheel bearings. So you have an outer hub and a wheel bearing hub which each contains a handful of individual parts.

You could also be getting noise from the axle shaft u joint, ball joints or maybe your brake caliper is falling off.

Turning the front driveshaft by hand likely means that the tcase is in 2wd and your outer hubs are disengaged. So look at the driveshaft u joints, and the axle shaft u joints. Look for a broken axle shaft.

You could be hearing any of those while driving in 2wd because there is the possibility of viscous friction in the tcase that would turn the front driveshaft even though it isn't locked in.

 

[nvrenuf]

Do you still have auto locking hubs?

 

[Jaymitch]

Thanks for responding.
Yes. I still have the auto locking hubs.
The driveshaft u joints, axle shaft u joints are ok. I will check the axle tomorrow.

 

[AV8TER]

You can turn the driveshaft by hand and the auto hubs don't lock up? I think you just answered your question.

 

[Wes Harden]

check and make sure all your wheels are tight.

 

[nvrenuf]

Yeah, I’d look really hard at the auto hubs - they will fail eventually.

 

[K5Jimmy]

The vibe is in the steering wheel? Or the seat.