990 rear diff problem

[kenmore99]

This is a 7yo 350 hr tractor but I only bought it 1.5 yr ago from a friend who i know took care of it and didnt abuse it (of course,thats debatable now)--so I am considering buying a new tractor bc I want one that is going to last 15 years at least and if the rear end drops out at 350 hr, what does that say about the condition of the motor and other components--I cant buy a tractor in 2 years with 2 kids in college so its either suck it up and pay now or pay more later--either way I realize I'm screwed financially but this is my only toy and I work hard for it...thanx

 

[arrabil]

if the rear end drops out at 350 hr, what does that say about the condition of the motor and other components

The rear end says absolutely nothing about the other components.

So did you use the diff lock a lot?

 

[kenmore99]

I've never used the diff lock in the 45 hours I've had the tractor--and the wheel bearings having to be replaced? thats why I'm skittish on this tractor--what do you think other than abuse could cause this at 350hrs?

 

[kenmore99]

Final repair bill today--2450$-included a new "spider gear" for the rear diff and new wheel bearings and regular servicing--spoke with the JD manager and he said the tractor is a tank,looks good and chalk it up to bad luck so I've settled down and going to keep it for now and Craigslist or ebay if it acts up again and go tractor shopping..thanx

 

[arrabil]

A spider gear normally won't break unless you really put a lot of torque to it, like while you're stuck, or its just a freak thing. I'd be keeping it.

 

[RoyJackson]

A spider gear normally won't break unless you really put a lot of torque to it, like while you're stuck, or its just a freak thing. I'd be keeping it.

Yep, I agree...unless there was a defect in the casting or billet that wasn't found.
That dealer is right...the 990 is a tank and you were just the unlucky recipient of wha may have been a manufacturing defect (or the previous owner did abuse it without realizing it).