MFWD problem on 790

[WartsilaDiesel]

Wondering if anyone else has experienced a mechanical problem like mine? I have been doing some selective clearing on land adjacent to the house; this has involved removing stumps with 7BH, moving fieldstones with 419FEL, and backdragging the grade to uniformity. I have been shifting the MFWD in gear as needed for traction, but have been very careful not to have MFWD engaged on hard, high traction surfaces, or when traveling around the jobsite. Well, tonight I was taking the tractor to the barn, with MFWD not engaged, when the left front wheel stopped rotating. I could back up approximately one wheel revolution, and it would lock up again. This is definitely a mechanical interference. The lock-up is intermittent; I was able to get indoors by proceeding slowly, while backing up to 'free' the wheel as needed. So, has anyone had any similar issues? 790 has only 57 running hours.

 

[chickenman]

you may have a broken gear tooth

that may cause the symptoms your expericeing

 

[RobS]

Definitely does not sound normal and something I've not experienced with my 790. Still under warranty? Good luck and let us know how it turns out /forums/images/graemlins/smile.gif

 

[WartsilaDiesel]

I talked with my local JD service department this morning and they'll be right out to pick the tractor up. Over the phone, they thought it might be a gear or bearing failure since there is nothing but wheel hubs and a differential for moving parts in the axle. Fortunately, I am still in the warranty period; the information I have shows Powertrain on CUT's warranted for a term of 36 mo. / 2000 hrs.

 

[rjp444us]

You have broken the spur gear ask to see what it looks like I will put money on it that it looks like it melted in there.
Seems that JD has some problems with quilaty control the gear was not proplery heat treated
Ask to see the pices and let us know.

PS the same thing happened to me.... /forums/images/graemlins/shocked.gif

 

[WartsilaDiesel]

Problem found! Nine teeth on three of the right angle bevel gears between the axle and wheel hub were sheared off to the root! My dealer thought driving on high-traction surfaces with MFWD engaged would be the cause of the problem; however, I know this is not a contributing factor because this is not how I have treated my machine! I am inclined to agree that the heat-treating or hardening process was inadequate during the parts' manufacture.

 

[regor66]

How did this turn out? I have the same problem with my 790 after 130 hours. Did the dealer stand by the warranty? Curious to know before I approach my dealer. Thanks

 

[regor66]

Took my tractor to JD dealer this morning. Most of the teeth on the 3 90 degree gears/pinions are damaged. This is on both sides of the axle in the outer hubs. Metal pieces got into the ball bearings and locked them up. Service manager said they have seen this before on CUT's with loaders. Said it happens more often and worse with loaders and no weight in the rear tires. My rear tires are filled so I'd hate to have seen the damage if they weren't. Looks like warranty will take care of it this time.