856 trans noise

[Brokentractor71]

Went and looked at a 856 that's for sale. Engine sounds good and as it was sitting there idling a noise develed like a knocking noise in the center section of the transmission. If you hold down the clutch pedal it stops. Could it be a bad bearing? Noise sounds like it's towards the rear of the center section.

 

[caterpillar guy]

Could be a bearing or a gear .Was this noise more at the clutch area or more back further? If further back probably the gear or bearing .IF more by the clutch then more likely the Live drive spline at the pressure plate. they get worn and will strip the spline out of the pressure plate or shear the rivets holding the spline. The throw out bearing is also a possibility as most don't realize the bottom cover has to be removed to grease it or just don't bother. We put a short hose and fitting in that hangs below the cover so it can be greased without bothering with the cover.

 

[Brokentractor71]

I'm ruling out the live drive because the noise stops when the clutch pedal is pressed down. Noise seems to be at the rear of the center section.

 

[caterpillar guy]

Back in the center section would be the speed transmission section I suppose it could have something to do with a bearing or gear or possibly the TA though I would tend to doubt that. Range section tends to have more trouble than the speed section. Range is under your feet setting in the seat. Speed it right under the fuel tank behind the clutch. Then the Ring and pinion is behind the range section. IF a bearing was going there could be an expensive deal. All of it would require a split. Maybe 2 if it was in the TA.

 

[used red MN]

Went and looked at a 856 that's for sale. Engine sounds good and as it was sitting there idling a noise develed like a knocking noise in the center section of the transmission. If you hold down the clutch pedal it stops. Could it be a bad bearing? Noise sounds like it's towards the rear of the center section.

Could you or did you drive it? Or not that serious about purchasing it yet? If you don’t hear it driving under a load with the brakes it is probably just chatter from gear back lash when gears are turning with no load. Or at least if it goes away under load it likely isn’t a chipped or missing gear tooth. Could still be a bearing though.

 

[Fritz Maurer]

What used red said. A Ford 9700 with high hours will make a horrible rattling sound at just the right idle speed ... it's the PTO shaft with loose splines driving the hydraulic pump... goes away at any other speed and there's really nothing wrong with it.... other than the drive coupling on the flywheel .

 

[caterpillar guy]

Not going to say it can't be but with all three being almost identical 806,856,1466 and none of them have a rattle at any speed. The rearend will howl on the 1466. that is the rear end gear set adjustment with probably it being off just a tad and I'm not going to take it apart just to change that.