broke the front end

[Conservative1]

I did it this time, and am looking for some info. While pulling a downed tree in reverse with my JD790 (MFWD, FEL, LX5, 150 hours) I broke something internal in the front end. I heard it pop, and was pretty sure I had goofed up. Sure enough, I took off toward the shop after taking her out of 4wd, and after 40 feet, the front left tire locked up tight. I put her in reverse, backed up to a spot out of the way, and shut her down.
I'm sure I've sheared a gear tooth or three. Is this a difficult repair? How much might a new gear be? should I just let the dealer (my dealer is the best within 100 miles) fix it and just suck it up financially?
I'm pretty mechanical, and can do bolt off and on type repairs. I have wrenches, torque wrench, ect... I'm pretty well set up in the shop, I'm just wondering if I am better off letting them do it.
I broke it- no doubt about that. I know now... don't try to pull too much weight in reverse. I think one front tire was in soft dirt, and one must have hit a rock. Not sure yet if the broken part is in the diff or the hub.
Any advice? How bad have I hurt my baby? /forums/images/graemlins/confused.gif /forums/images/graemlins/crazy.gif

 

[beenthere]

If me, Id jack it up and drop the front end off, and take it apart to see what is going on. Then when finding the trouble, look into buying the parts. If at any point I'd run out of 'smarts' to continue or 'suggestions' how to finish it, I'd take it to the dealer for a fix.
I'd do this with the dealers' knowledge and okay, but try to use it as a learning experience. Now all this is if I had the time and the interest. Also, if the tractor is where it can sit on blocks for awhile.
Not fun to break them, but sometimes it happens when we find the 'weak' spot.

 

[RoyJackson]

The first thing you'll want to do is determine if you're still in warranty. If you are, you may want the dealer to look at this. Once you start tearing down anything (going beyond normal maintenance), you risk voiding any warranty.

That said, your dealer sells a CD-ROM tech manual for the x70 and x90 series tractors. It'll cost you about $50. Once you have that manual, you can determine if your skills are up to the task.

The MFWD axle tear down is section 50-30.

Since your left wheel is locked up, it may be the bevel gear on the end of the left axle, or it may be further in. You won't know until you get there.

The only thing that would give me pause about tackling this job would be setting backlash on the gears. I've never done that. That's not specified in the manual and may not be required since these machines don't go very fast. If you're tight with your dealer, one of the service technicians may be able to offer suggestions.

 

[AntrimMan]

Thats good advise above and in good order too.
Keep in mind that out of waranty there is no $75/hour charge for any labour you put into it. Taking the unit off and bringing it to the dealer and then reinstalling it your self will save you a few duckets. You will need a sheet of plywood or something similar to work on if you can't get it to the shed. It's more pleasant than lying in the dirt.
All the best,
Martin

 

[MMM]

On my tractor, lash has to be printed and set with shims. Probably best left to Mr Greenwrench.

 

[tdi1fun]

First of all, sorry about your breakage.
This goes to show why many manufactures call the 4WD, on compact tractors 4 wheel assist. Normally they cant take the full torque of what the tractor can produce. I would try to get them to fix it under warrantee if you still have it.

 

[BB_TX]

I would certainly look into a warranty repair if that is possible. But since you did not mention warranty I assume it is either out of warranty or you assume they would not honor what you did to it.
I have a 950 MFWD. A couple years ago, the left front drive unit sprung a major leak. Assuming it was just a seal, I took it off and completely dismantled it. All parts, including the gears, were laying out on the floor. A bearing had come apart and broke the seal. So I replaced all seals and bearings. But dismantleing it and putting it all back together was really not much of a problem. Obviously it took me longer than a JD mechanic as I had to feel my way thru it, but not that bad. But I did have a service manual and a parts manual that made it much easier. If you plan on keeping the tractor for a long time and do any work on it yourself, I would recommend getting both manuals.

 

[Conservative1]

Wanted to update y'all. I spoke with Mike at Rowland Implement in Lebanon, Tennessee today. Mike sold me the tractor, and has gone above and beyond to help with repairs if I needed them, and overall advice if I didn't. They really are a great dealer, for anyone in Middle Tennessee. I HIGHLY recommend them!
Anyway- warranty is gone, I've been out of warranty for two months, and I knew that. Besides, I don't know if I would let this be fully warrantied even if I was still in... I was trying to pull in the wrong direction with too small a tractor, and I broke it. Mike said he'd recommend I bring it in to them, due to some complexities with setting lash on gears and getting it RIGHT. He says price will be between 300 and 600... 600 being the worst case scenario.
I'm gonna let the experts handle this repair.
I appreciate all the advice a lot! I'm lucky- I have a dealer who I trust to not only do the work, but to do it fairly. I might as well use that...
C1

 

[Egon]

</font><font color="blue" class="small">( I was trying to pull in the wrong direction )</font>

Seems I am confused with this statement. Why can one not pull backing up?

I really do not think you did anything wrong.

Egon

 

[RobertN]

The primary strength in most ring/pinion gear setups is in the forward direction. It's the way the gears mate up, and where most of the material on the gear is.

I popped the diff in my old Jeep pulling my b-in-law out of the snow. He was in front of me on a trail, so the easist way was to yank him out backwards. He was stuck pretty good. We chained up, and on the third tug we all heard a pop. Popped that ring gear! I have seen others do it too.

If there will be stress involved, it is best to always pull forward if possible.