Hi I just bought a new to me cat 12m model 2008 serial B9R00079. Since I bought it at an auction seller mentioned that it only moves while the diff lock is engaged. Motor grader finally arrived(to mexico) I drove it for a while and it shifts up and down perfectly on the dash fwd, reverse etc. But it only moves If the diff lock is engaged. If you disengaged the dif lock it will still shift up or down on the dash screen but it won't move not until you engaged the diff lock again. I haven't had my mechanics to take a look at the tandem chains or anything related to. What do you guys think could be the cause and solution for this issue knowing that the machine shifts but only moves if diff lock is on. Thanks for your help and also wanted to congratulate all the members of this forum for sharing your knowledge to guys like me.
Something broken on one side
Assembly part number 365-2125. Because the other one is LSD lock
Remove the covers and start inspecting
I’d hate to disappoint you - but you’ve picked the machine with the worst engine ever made.
Lift the back of the machine off the ground, put it in gear with the diff lock on and see if one side doesn't turn. Turn that side by hand and see if both wheels turn together or not. If not, you've got broken chains. If so, you've got something broken between the chain case and the diff. Or if nothing else it'll tell you which side the problem is on.
Little harsh.
To the guy - yes. About engine -I hope it’ll work out for him.
What engine does she hide beneath her louvres ?
C7.2
I'm betting snapped axle shaft. Usually broken chain balls up and locks that side.
And it’s pretty rare to have both broken. Unless it operated on one wheel on the same side lately
Thought it would of been a C6.6.
Those ain’t THAT bad. I have nothings against C7. C7.2 - thats another story!
I will do that tomorrow, I thought it could be somehow electrical related but I guess it doesn't. I'll update tomorrow
Would love to hear your update @chine61