Engine/Transmission (1994 - 1998) Pilot Bearing (How do you know?)

[Tardog]

How do you know when the pilot bearing is gone in the flywheel. My NV4500 has begun to make a rattling type noise in all gears (very noticable when in 1st and idling up hill when the motor pulls a bit). How can one determine if it is the input bearing or pilot bearing befor he takes the transmission out? or can this be determined? Thanks about 120K on the transmission. Any hints?

 

[Hoefler]

Pilot bearing will give a vibration that will lesson when the clutch is depressed. It will make noise with the clutch depressed also. Most likely you have a input bearing or a main shaft bearing bad. If it goes away or lessons considerably when you are in direct gear, it would be a pocket bearing or counter shaft bearing. If it lessons when you back off the throttle, it is in the rear end. It could also be a carrier bearing if you have one. The drive shaft does a remarkable job of transferring noise from the rear.

 

[Heepdriver]

A pilot bearing will never make any noise with the clutch ingauged, pedal up. If you have noise with the clutch ingauged it is in the transmission or the throwout bearing. This is not to say that the pilot bearing may not be bad or at fault for related damage.

As soon as you ingauge the clutch the crank, flywheel, clutch assembly, and input shaft all lock together. there is no differentation of speed for there to be any bearing movement or rotation.



Just one of my pet peeves of common mechanical misconceptions.

 

[Erniek]

I had a throwout bearing go bad in an old mustang once. Made a heck of a lot of racket with the pedal pushed down (when the throwout bearing is in use). When the clutch was "engaged" driving down the road, it made no noise at all, because it is just sitting there at this point doing nothing. Just my 02 worth

 

[K5IP]

Sounds like a transmission problem to me. Is it as noisy in high (4th) as it is in other gears? If it is quieter in high, it is a transmission bearing problem. 4th is straight through and all the side loading between the main shaft and countershaft goes away, i. e. quiter.

Rog