5-speed bearing noise?

[Gomez]

The transmission shifts good, nice and clean oil (drained and inspected). No other noise but a constant swishing sound while driving down the road, even in neutral. What can it be? This truck does pull heavy loads now and then. But is not abused. Is there something that I can check without pulling the transmission to determine what is making the noise?

 

[JHumphries]

I believe a worn throw-out bearing can make that sound. Does the sound go away when you press the clutch? Does even a little pressure change the sound?

 

[Gomez]

Thanks for the reply, the sound is constant while driving down the road. No difference if clutch is engaged or not. The noise is getting louder now. I pulled the PTO plate off and everything looks perfect! Is this a common problem? Almost everything I read says that the gears or case goes bad first. Thanks...

 

[JHumphries]

Does the noise change with road speed?

Does the noise happen when sitting still?

If it only happens while driving:

Does it still happen in 4 Hi? 4 Lo? Transfer Case in Neutral? (All of this while rolling down the road. )

Also, check the U-joints for any slop.

 

[Gomez]

Okay, now the the transmission is only making noise in 5th gear, all other gears sound normal. could this be synchronisers or gears or what? Could I run the truck without using 5th gear, or will it hurt something? Does anyone know about how much a rebuild will cost? Thanks.

 

[pepecat]

I think it is the throwout bearing. The type we have on the diaphragm clutches are spinning all the time, even when the clutch is engaged. In this case, you'll hear it all the time when the t/o bearing goes bad.