Front Differential TROUBLE!

[billboe]

JBS,

The rear support that holds the front axle on the tractor "normally" has 4 bolts. Mine only had 2 bolts remaining and the other two were very loose! This must have allowed movement of the front axle that caused the pinion shaft to break. Like I said in my first post, this could have been avoided by a bit of vigilance of bolt tightness...

This just gave me a thought... I did an oil change about 30 hours ago... One would think that I would have noticed those bolts being loose... In those last 30 hours, I've done quite a lot of driving on the road... I wonder if that caused more vibration which caused the bolts to loosen!?!? Just speculating...

The tractor has about 1100 hours and it has been very reliable and a hard worker.

 

[Ozarker]

Those bolts should never have come loose. Either they weren't properly installed at the factory or someone else has had it apart and failed to properly install them.

 

[karmakanic]

Hi billboe,

As the others have mentioned, replacing a ring and pinion and the subseguent set-up of the same is a very exacting and tricky business. These gears are hypoid gears, and they are only sold as matched pairs because the clearence between the teeth must be absolutely perfect or they will whine or give short life. This means the set-up has to be perfect also. Along with the backlash and pinion depth, you must also get the preload on the bearings correct. A dial indicator, machinist blueing, and an inch pound torque wrench are some of the tools you bring to this job.

But, there is one way you could do this job yourself. And that is to purchase a good used "third member assy". The third member, or pumpkin, as it's sometimes called, consists of the gears shown in your parts image all bolted togeather and set up in the cast iron housing. You simply pull the old one out, and replace with the new (used) one. You will have to remove the axles, but other then that is bolt out-bolt-in.

Of course, this assumes you can find a good used one, I'm not familar with used tractor parts, so I don't know about availability.

I can advise you how to tell a good used one from a bad one. If you decide to go that way, and need any help, just drop me a email.

Dave Perry

 

[jbs]

Bill,

Thanks, I forgot about the loose bolts in your orginal post. I'm sure that had a lot to do with the failure.Seems to be a lot of post about loose bolts, guess that needs to be a part of our pre-operation check list. Looks like I will have to order a case of lock-tite!

 

[dgood1]

jbs,

Just remember that the strong red stuff will make it real hard to remove the bolts later. You might want to go with the non-industrial strenght.

Don

 

[Soundguy]

Our heavy service trucks and heavy equipment all use matched sets of ring and pinions.. most manufacturers won't even sell them any other way.

Soundguy

"If you broke the "pinion" gear (the one you pointed out), you will probably be forced to buy the ring gear along with it. A lot of these come as a set and are meant to work together. Not necessarily true in cars/trucks, but I have had this experience with tractors and equipment."

 

[jasonf]

They do infact engage each other, They need to have a fairly tight/exact fit togehter. Usually there are shims that are purchased and installed in front to the pinnion shaft that you broke. This will allow the gears to mesh correctly and overcome some variation due to the casting of the housing assembly. You need the shop manual for this so that you know what the acceptable 'play' in the gear mesh is. You actually coat the ring gear with prussian blue dye and spin itwith the pinnion gear to leave marks on the ring gear. This will show you how the pinnion gear is hitting each tooth on the ring gear. You then add/remove the shims until you get the proper 'wear' pattern. If this is not done you will get alot of noise out of the differential, as well as shortened gear life. This can be done by you, but you need the shop manual for the tolerances, as well as other helpful info. Hope this helps.....

 

[LarryC]

Been there, done that. First find a competent FWD mechanic and talk to him about working on it, second jack up the front end and remove the whole front differential, take it to him with the shop manual. After it's apart he can show you the parts you'll need in the manual, scoot to the Kubota shop and purchase them. My ring&pinion was about 350.00 and yes they came as a matched pair, if you have over 1000 hrs. on the machine replace the carrier bearings (on each side of the ring&pinion) and all seals it's cheap insurance as long as you have it apart.
The ring &pinion have to be meshed perfectly, the mechanic will need to have the shop manual to know these specs. Total for mine not including labor was 500.00, this is not brain surgery and can be accomplished by any competent FWD mechanic but unless the R&P is setup correctly it can be toast in one hour. Make certain you have a jack under the diff. to lower it after unbolting, two people can load it in the back of a pickup, hope this helps.

 

[billboe]

Thanks for all the posts... I currently have the front end off and in pieces... /w3tcompact/icons/eyes.gif The new parts are on order and should be here by the end of the week. Besides the advice from all of you, I am getting advice and pointers from an expert, so, hopefully I won't screw it up too badly! /w3tcompact/icons/smile.gif

 

[Turfman]

Let us know how it goes.