L245DT Stopped Working in 4WD - Bolts for Front Differential Ring Gear Sheared - Pics - Repair Summary

[Mountain Man Mike]

Thought the group may like to see the catastrophic failure in the front axle differential that just occurred on my L245DT causing the 4WD to stop working. I was able to remove the left axle tube assembly without removing the whole front axle assembly from the tractor. I was shocked to see the ring gear come out without the carrier and other gears. All six bolts had sheared off and were ground up and shredded along with shredding the large ball bearing retainer. I am attempting to recover now. I was able to remove all six sheared of bolts out of the carrier. I have thread repair inserts on order for the wallowed out threads along with a new bearing, "O" ring seal and six new Kubota bolts. Still have to get the damaged bearing out.

I've owned the tractor since new. Has around 2500 hours on it. 4WD up to this point has always worked fine. Never heard any noises or crunching. Fortunately all of the debris was contained to the outside of the differential gear carrier, hence no damage to the gears. I suspect the bolts started working loose one by one until they just sheared off.

Haven't found the torque rating for the ring gear to carrier bolts and the torque rating for the bolts for the axle tube assembly to the differential. If anyone has those specs please let me know.

 

[twomany]

Similar thing happened to my SL&H tractor.

Only I found out while replacing a broken front axle (overload! my fault, I snagged a root with the bucket curl )

$1200 repair. It's all good now ;-)

 

[rbargeron]

Well as differential failures go, I'd say this one was pretty lucky. To only need six new bolts and a gasket to restore operating condition is rare. Find some nice grade 5 or even grade 8 replacements - maybe use some permanent Loctite. Congratulations on qualifying for the Guinness Book of Records

 

[Mountain Man Mike]

Repair Summary Wrapup: Installed six high strength solid thread inserts in differential carrier. Used high strength Locktite retainer compound between ring gear and carrier to reduce chance of slippage in the future. Also used Locktite on the six new bolts and torqued them to specs. For added strength, to prevent any chance of slippage between the ring gear and the bolts I bored precision blind holes through the ring gear and into the carrier for 3/4" hardened .250" steel pins using Locktite and press fit. Also replaced both carrier bearings, replaced the left side outboard axle shaft bearing and two "O" ring seals. Added new gear oil to all front axle assemblies.

Got everything back together this afternoon and I promptly put the tractor to work for 2 hours smoothing out all the wild boar rooting in one steep pasture. Confirmed that the front wheels were being driven when in 4WD. So far everything seems to be working properly and smoothly. Thanks for coming along for the ride!

 

[Nicksacco]

Wow, that damage picture looks like the result of a blender!
Nice machine work and repair!

 

[William1]

Surprised with the failure, top notch repair!
The only over kill I might of done was safety wire the bolts

 

[North Idaho Wolfman]

Excellent repair job!