Slip Clutch/Gear Box Spline Problem

   / Slip Clutch/Gear Box Spline Problem #1  

AgMan

New member
Joined
Jun 15, 2013
Messages
22
Location
Alabama
Tractor
JD 5085M, JD 3720
I was hoping someone might be able to help me. The unit is a JD MX10, pull rotary cutter. The problem I have is where the slip clutch attaches to the spline on the gear box the bolt used to tighten the hub is not holding. Proper torque is being applied. Numerous time bolt wears and eventually breaks and assembly comes off. Purchased a new slip clutch. Any suggestions on what is going on?
See picture of bolt. Something is moving.
 

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   / Slip Clutch/Gear Box Spline Problem #2  
I was hoping someone might be able to help me. The unit is a JD MX10, pull rotary cutter. The problem I have is where the slip clutch attaches to the spline on the gear box the bolt used to tighten the hub is not holding. Proper torque is being applied. Numerous time bolt wears and eventually breaks and assembly comes off. Purchased a new slip clutch. Any suggestions on what is going on?
See picture of bolt. Something is moving.
I am not sure of the exact arrangement, but movement means wear is occurring. The movement MUST be stopped. If it hasnt worn too much, tightening more will cure it. ... What size bolt and Grade and what torque spec are you using?
larry
 
   / Slip Clutch/Gear Box Spline Problem #3  
splines may be worn to much for it to tighten up
 
   / Slip Clutch/Gear Box Spline Problem #4  
I am not sure of the exact arrangement, but movement means wear is occurring. The movement MUST be stopped. If it hasnt worn too much, tightening more will cure it. ... What size bolt and Grade and what torque spec are you using?
larry
splines may be worn to much for it to tighten up
Really?
 
   / Slip Clutch/Gear Box Spline Problem #5  
Is there is an area of the spline that is "scalloped" to provide clearance so the bolt can pass through without contacting the spline's teeth?

PTO stub shaft.jpg

I'm assuming that the bolt is offset & at right angles to the spline & secures a collar with internal splines.
Something like this:

PTO clamp bolt 0.jpg

It looks like the bolt is contacting the major diameter (OD) of the external spline teeth.
This creates a stress riser, which, combined with the tensile preload of the torqued bolt and cyclic loading of the PTO shaft, accelerates fatigue and failure of the bolt. I believe this is the failure mode that Larry SPYDERLK is describing.

I'm wondering if the bolt is correctly located in the clearance scallop of the external spline.
Was the external spline recently replaced or swapped?
Is the PTO shaft the correct length, or is it a bit too long, forcing the bolt into the spline teeth when the 3pt moves through the point where the shaft is at its shortest?

-Jim
 
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   / Slip Clutch/Gear Box Spline Problem #6  
Is there is an area of the spline that is "scalloped" to provide clearance so the bolt can pass through without contacting the spline's teeth?

View attachment 438684

I'm assuming that the bolt is offset & at right angles to the spline & secures a collar with internal splines.
Something like this:

View attachment 438683

It looks like the bolt is contacting the major diameter (OD) of the external spline teeth.
This creates a stress riser, which, combined with the tensile preload of the torqued bolt and cyclic loading of the PTO shaft, accelerates fatigue and failure of the bolt. I believe this is the failure mode that Larry SPYDERLK is describing.

I'm wondering if the bolt is correctly located in the clearance scallop of the external spline.
Was the external spline recently replaced or swapped?
Is the PTO shaft the correct length, or is it a bit too long, forcing the bolt into the spline teeth when the 3pt moves through the point where the shaft is shortest?

-Jim
Im envisioning a splined split socket that clamps on a spline gearbox shaft by tightening the bolt/ squeezing the socket closed. If its wiggling its ruining the fit. ... OP needs to respond with more info to give a better start point.
 
   / Slip Clutch/Gear Box Spline Problem #7  
My guess is if shaft leading to slip clutch is a telescoping type then the sliding section needs some "lubrication"!! Below is spec's on bolt I located in MX10 PC.
 

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   / Slip Clutch/Gear Box Spline Problem #8  
OP keeps monitoring the site but doesnt offer any more info. Wonder what thats about.
 
   / Slip Clutch/Gear Box Spline Problem
  • Thread Starter
#9  
Thanks to all who have repiied with ideas and suggestions. I just got in last night and have not been able to reply to your posts from my mobile device. All suggestions have been addressed and looked at. Correct bolt and nut being used (JD). New slip clutch was purchased because splines were wore. Splines on gear box shaft are in good shape. Tube is greased and movement is great. The tractor is now being looked at by a certified/independent JD mechanic. He is very puzzled and has opened, I think it is callled a D-TACK case with JD, where an engineer who is very familar with the MX10 will call him to discuss, reccomend suggestions or share if this has happened in the past.
All of your reccommendations have been addressed either before you suggested or yesterday when I was up at the site with the tractor. I will keep you posted the ultimate outcome.
Thanks
 
   / Slip Clutch/Gear Box Spline Problem #10  
How does the bolt hold the male/female splines together?

,,, Does it clamp them or only act as a mechanical key to prevent them from sliding apart?

,,,,,, What is the size and grade of the bolt? What is the torque spec used?
 
 
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