B2650 mmm vibration

[jasonr4491]

I recently bought a b2650 with a 60 inch belly mower. From the first time I mowed with it, it's had a vibration/deck rattle when the mower is down mowing, raise the mower up and it goes away. Told the dealer and we agreed it was probably a driveshaft issue. He swapped me driveshafts from another new mower and it has the same problem. Both shafts seem to have a lot of slop both on the splines and the splines where it attaches to the tractor. I was just looking for ideas and suggestion before I take the tractor back to him.

 

[85Hokie]

I recently bought a b2650 with a 60 inch belly mower. From the first time I mowed with it, it's had a vibration/deck rattle when the mower is down mowing, raise the mower up and it goes away. Told the dealer and we agreed it was probably a driveshaft issue. He swapped me driveshafts from another new mower and it has the same problem. Both shafts seem to have a lot of slop both on the splines and the splines where it attaches to the tractor. I was just looking for ideas and suggestion before I take the tractor back to him.

slop??? that should not be - the pto should be very tight. The slide should be lightly greased able to move somewhat freely - it needs just a little push pull to move, no where is there slop.

Since you swapped the shaft - how about the connection at the top of the MMM, is that "working" as it should? DID he swap out just ONE half of the shaft or the whole shaft? Is it at all possible that the shaft is 180 degrees out - not sure that is possible.

 

[jasonr4491]

The whole shaft was swapped out. It's not possible for the yolks to be misaligned because there's a spot weld on the splines and will only couple one way. The splines on the gearbox are tight, it's clamped with a bolt. The slop/ loosens I feel is where the locking coupler slides on the tractor PTO. So much looser than the bx kubota I had, some times a struggle to slide it on and lock. It's hard to believe kubota would engineer so much tolerance in 2500rpm shaft. Second shaft both new.

 

[85Hokie]

The whole shaft was swapped out. It's not possible for the yolks to be misaligned because there's a spot weld on the splines and will only couple one way. The splines on the gearbox are tight, it's clamped with a bolt. The slop/ loosens I feel is where the locking coupler slides on the tractor PTO. So much looser than the bx kubota I had, some times a struggle to slide it on and lock. It's hard to believe kubota would engineer so much tolerance in 2500rpm shaft. Second shaft both new.

If it is so loose at that point - why is it so hard to lock? Are the spines correct? I cannot imagine that is would rattle there, even on my 53 ford jubilee it was a snug fit after 60 years of use. Something isnt right, down it vibrates and up it does not, have you taken a good hard look at uni joints??

 

[Tooljunkie]

U joints exceeding proper work angles?
Output side on tractor and input on mower need to be parallel.

 

[85Hokie]

U joints exceeding proper work angles?
Output side on tractor and input on mower need to be parallel.

That would be hard not to achieve, I would think both a fixed in a horz position.
maybe there is a bolt or holddown that is loose.