Front Differential TROUBLE!

[billboe]

I'm guessing this is going to be expensive!!!

The "7T Spiral Bevel Pinion Shaft" broke on my L2850... This is the shaft that connects to "Propeller Shaft" (I'd call it the front drive shaft..). I'm not sure if that is the only problem. I've only removed the propeller shaft so far.

Questions...

Will I have to remove the whole front axle case to get at this part?

How complicated is this job? Will an average home tractor owner (reasonably mechanically minded) be able to handle it?

What will it cost to have a shop do this?


Looks like the cause was some of the bolts holding assembly up came loose and let things drop... Lesson learned is that you need to get under the tractor and check bolt tightness frequently!

I'll attach the drawing from the parts list... Like I said, I don't have it all apart yet, so, I'm not sure if any of the other parts are damaged. At any rate, it looks like the part I'm interested (160 in the pic) seems to come in an "assembly" (read: "more money")... The parts list is below...

Oh well, #$@#$#$ happens!

Just looked up the part on Tractorsmart... OUCH!!!

Original Part Number 31353-99120
Current Part Number 31353-99120
Description GEARS, BEVEL ASSY
Pack Quantity from Kubota 1
Price Each $316.26


FRONT DIFFERENTIAL
010 31353-43312 CASE,DIFFERENTIAL 1 1.62 3.564
020 31353-43330 SHAFT,PINION 1 0.13 0.286
030 05012-00628 PIN,STRAIGHT 1 0.006 0.0132
040 31353-43340 PINION,DIFF. 2 <=56141 0 0
040 31353-43343 PINION,DIFF. 2 >=56142 ¬ 0.1 0.22
050 67121-56670 COLLAR,PINION THRUST 2 0.006 0.0132
060 31353-43350 GEAR,DIFF.SIDE 2 <=56141 0 0
060 31353-43353 GEAR,DIFF.SIDE 2 >=56142 ¬ 0.19 0.418
070 67211-15160 SHIM 2 1.0MM 0.01 0.022
070 67211-15170 SHIM 2 0.8MM 0.008 0.0176
070 67211-15180 SHIM 2 1.2MM 0.01 0.022
070 31353-43360 SHIM 2 0.6MM 0.01 0.022
070 31353-43370 SHIM 2 0.4MM 0.01 0.022
080 31353-43413 PIN,STRAIGHT 2 0.01 0.022
090 36280-42320 BOLT 4 0.042 0.0924
100 08101-06009 BEARING,BALL 1 0.22 0.484
110 31353-43440 SHIM 1 0.4MM 0.005 0.011
110 31353-43450 SHIM 1 0.6MM 0.01 0.022
110 31353-43460 SHIM 1 0.8MM 0.01 0.022
110 31353-43470 SHIM 1 1.0MM 0.01 0.022
110 31353-43480 SHIM 1 1.2MM 0.015 0.033
120 08101-06209 BEARING,BALL 1 0.42 0.924
130 31353-43510 SCREW,ADJUSTING 1 0.16 0.352
140 31353-43530 WASHER,LOCK 1 0.012 0.0264
150 01023-50610 BOLT 1 0.005 0.011
160 31353-99120 ASSY GEAR,SPIRAL DT 1 7-34T 2.3 5.06

 

[RoyJackson]

If you don't have a shop manual, I don't think you want to tackle this job. Manuals are good, but most I've used assume you have certain training and/or experience.

Have you ever had an automotive transmission or differential apart? Any experience like that? Do you know what "backlash" is? If you can say yes to those questions...you can probably do the job. If you can't say yes, you might want to leave it to the professionals.

I'm no mechanic (too slow, for one thing)...everything I've tackled that was beyond normal maintenance, I've had a mechanic friend lend guidance (and his tools!).

 

[billboe]

Hello Roy,

Yes, I do have the shop manual... And no, I haven't had an auto tranny or differential apart... Do have a handy friend/neighbor...

 

[jbs]

I'm not sure about a tractor but if its anything like a "pumpkin" on a vehicle I would not attempt it without some help. Proper installation is determined by the expertise of the installer i.e. pre-load, backlash, tooth pattern etc. Im sure some of the other members can give you more advice. Like you I sure would hate to pay that dealer labor..........good luck and keep us up to date

 

[AMP]

I am an auto mechanic,that is what we call a ring & pinion gear. Without proper tools and knowlege the price you pay the dealer will be cheap.

 

[GSS]

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.

You could probably save a little money taking it apart, but I would leave the repair to someone familiar with differential gears. Getting them setup correctly is tricky and, like others said, require specific tools. If it's not done right, you could be looking at getting another set of gears in a very short time... and they ain't cheap.

my 2 cents...

- G

 

[billboe]

Thanks to all for the advice... Yes, I have already "split" the front-end and I am contemplating whether to continue myself or punt to someone who has done it before...

GSS, you are correct, the part comes as an "assembly" with the other gear indicated in the drawing (see pointer #160). It seems strange you can't buy them separately; they don't even seem to contact each other!?!? Oh well.

I'll keep you all informed...

 

[GSS]

I believe they do in fact contact each other. You can't see it from the diagram, but the ring gear (160) has teeth on the other side that the pinion gear meshes with. I grenaded my pinion on my rototiller and discovered that it was part of a set and not recommended to replace only one without the other. The set was almost $400 too! Installation would have been more. Luckily, I was able to get a competant welder to repair the broken pinion and it's been working great since.

You may want to ask local 4x4/offroad shops to look at it and give you an estimate. I can't imagine this being much different than a truck differential, but they'd know for sure. You never know what a tractor dealer will try to charge you for this...

 

[jbs]

Bill, I ment to ask this on my previous post,but could you give us any info on how this might have happened. Hours on your tractor, what has been its primary use,did this happen while performing a specific chore etc ?? Just curious because drive train parts or normally yery strong steel with numerous special heat treatments............. thanks and good luck

 

[MDNick]

Strange,

The L2850 I used on the golf course also busted front axle drive train components once. I do not know what parts as they were working on it over the winter and I only saw it briefly when I was home at Christmas from college. The course superintendent (aka greenskeeper, head mechanic, electrician, general all around everything) repaired it. He was very mechanically inclined, though sometimes tended to patch, not repair. Usually due to lack of funds, though.

I assure you, that little L2850 got the crap beat out of it constantly. It was abused, worked to death, over heated almost constantly. It was the primary tractor for a 9-hole very hilly golf course. We needed about another 15 horsepower, but it did the job. The fact that someting broke was expected, not amazing. I brush hogged stuff that was twice as tall as the exhaust stack, the radiator would plug up, the tractor would get hot. We'd clean it off, let it idle for 10 minutes, she'd cool down and we'd be off again. Pretty regular abuse was 'par for the course'. /w3tcompact/icons/grin.gif This was in the early-mid 90's. That tractor is still in use on the same albeit now 18-hole course.

Hope it's not a fault of L2850's.