My o2 ST, when its on centre stand and not running. When you spin the rear wheel you can hear and feel a clunking. You can also feel this whilest riding. The chain is not overly tight, no tight spots either ? The clunking is not loud but definately noticeable. Sounds as if its from the gearbox. Have checked the front sprocket and thats fine? Any ideas?

You have to jack the vehicle off the ground, then grab each tire at the 12:00 and 6:00 positions. Then as hard as you can try to wiggle the tire up and down. If there is any movement then that wheel bearing needs to be replaced.

Is it a one piece wheel hub bearing?

If it has 120,000 on it-- change both sides

The bearing & race type, you take apart & wash
off & look at for wear & markings & replace or
grease & return to service

If you hear a noise from 25 to 40 mph
On a rear drive car, you can remove the
brake rotor & feel the worn bearing --sometimes

You may be able to do that

I would just put the bearings on your Preventative
Maintenance list for 100,000 plus & change them
when you get there

Your Oxygen Sensors go at 100,000

Spark Plugs every 3 years & so on

I don't wait on failure,only as a learning tool,
then those items get added to my list

At best as I know the 2005 Prado is all time 4WD vehicle.
Is the engine running ? Can you shift the gears ?
May be something is broken in the drive train...
As a suggestion you can go home by locking the centre differential, proceeding at low speed and checking for noises .
Pls. let me know if it helps...

a wheel bearing can make a roaring sound from the rear wheels feel the tires for a rough tread if they feel smooth then jack it up and spin the rear wheels you might hear the noise while spinning by hand

yes that is normal as when you do this you are puuting the bike in gear and with the rear wheel of the ground the engine ticking over is just enough to get the rear wheel spinning but not always enough momentum hence the clunking sound of the engine

Get the rear wheel off the ground and adjust the chain tension. When checking the tension spin the rear wheel and check that the tension does not go slack or get tighter. If the chain is riding up and down the sprocket teeth then the chain is stretched and needs to be replaced. This is the grinding/clunking noise you are hearing. If the sprockets are worn consider a chain and sprocket set, it can be a less expensive option than buying the parts separately.

CLUNK NOISE YOU HEAR IS WORN CV JOINTS.

You could have a failed wheel bearing. Jack the rear up with the trans in neutral (chock the front wheels please) and try to spin the tire. it should spin fairly easy. If you feel grinding or the wheel is difficult to spin then I would say it is the wheel bearing.

check your cluch cable it may be sticking up also check you have free play on this cable,, put the bike on its center stand and spin the rear wheel with the bike in gear holding the cluch in as you spin the wheel if it spins ok the cluch is letting go

If the steering head bearings are bad you might feel a click when you pull on the wheel. If you can get the front tire in the air by putting the bike on a jack (and securing it there), pull forward on the front wheel. There should be zero movement front to back. If you feel some then either your steering head bearings are bad or your wheel bearings. While the bike is in the air, turn the handlebars slowly back and forth. Often you can feel a "notch" if the SHB are bad.