Quote:
Originally Posted by 30aadoodlebug
But when in third gear, if I let off the gas I get a very faint whine from the transmission. Its does not do this at all in second gear, or when the car is accelerating, only when coasting. When the clutch is put in, there is no sound at all, so that takes the differential thought out of the equation.
Jon
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Hey Jon....You mention that when you disengage the clutch (while coasting in 3rd gear), that the WHINING sound disappears. You also state that you believe that this fact seems to absolve the differential from being the culprit.
The other symptoms which you describe, in my opinion, seem to absolve the transmission itself as the culprit. While the transmission is in 3rd gear, there is obviously NO gear reduction as you would have in 1st or 2nd gears. As such, there are only two gears in play, and the meshing of gears is normally where any "WHINING"-like noises originate. The two gears in play while the transmission is in 3rd gear are the INPUT meshing with the CLUSTER gear, and the PINION gear meshing with the RING gear in the differential.
While the transmission is in 3rd gear, the driving force is transmitted straight through from the input shaft, and directly out the main shaft in the transmission. The load on the INPUT & CLUSTER gears' meshing never comes into play if you merely engage or release the clutch. That meshing (while in 3rd gear) only serves to turn the cluster gear, which turns anyway, any time that the input shaft turns.
On the other hand, most of us know that car "NOISES" can sometimes be very difficult to pin-down to a definite location. And since your differential is solidly connected to the transmission via the torque tube/drive shaft, the WHINING noise could easily be transmitted from the differential.
The particular WHINING you describe, along with the circumstances of loading and unloading that ring & pinion gear by engaging and disengaging the clutch is definitely symptomatic of a failing PINION BEARING. I believe that if this were my car, I'd look into this possibility and try to diagnose this problem with at least a definite place to start.
Coop
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