Thread: Isuzu MSA Gearbox to LT230

Originally Posted by Vern

It would have flexed under load, but in saying that boof ed broke his AFTER his housing was repaired.

boof ed, broken shaft picture is a little different yours but are in reality the same, i am saying this with out having the shafts in hand.


the scalloped for want of a better word, edge is an indication of compression and stretch. the same way Glass breaks, very hard on the out side soft in the middle. or bending a tube, the inside compresses the outside stretches, and collapses. this is what i am seeing from both sets of photos of your broken shafts.

bood ed shaft show a initial crack. this is typical of torque fatigue. But the fact that it is in the hard or case-hardened affected area, and that is it so short and looks shallow. add that to the scallops and i will bet the cow on torque not being the issue. and that alignment is the issue. actually i will not bet i will state.

so in the case of boof ed. i would say the damage was done before the patch up job.

based on what i have read. and lets face it theres a lot of rubbish writen to sift though.

if the adapter housing is letting go, the the weight of the motor transfer case etc all bouncing around. ALL this energy is going to end up being absorbed by the spud drive. = no brainer it broke, i wonder why duh.

is the adapter housing broken because of? it was not made well?? incorrectly installed?? abuse ??? post mods?? i have no idea!!!

maybe it broke because of the accumulative error in alignment of all the working faces 5 by my count. add to that the weird mainshaft design in these boxes and the amount of flex from that. i am leaning to the thought

the accumulated effect of missalinment of 5 working faces, including the energy defection. torque defection weight load and inertia forced working on the adapter housing lead to that components fail. this was followed by the spud shaft failing.

since this thread and the others have concentrated on the spud shaft, which in my opinion is a symptom not the problem.

NB if you case harden anything, by any method. it will be less elastic and more brittle. that's a fact. case Harding is and should be only for wear faces or to minimise defection over length. IE effectively turning a solid shaft into a mechanical tube

Originally Posted by Vern

Just had an interesting conversation with sheldon

AND?


( How is his mog going) ?