SMTA rear end

Mike Schwartz · Mar 6, 2009

Found some bad news on my SMTA this evening, I was draining all of the oil out of the rear end when I found bearing pieces in the bottom of the case. No pieces were found in the TA, tranny or PTO drains. Pieces were from a ball bearing with approximately 1/2 inch balls. Also found a lot of cage pieces. Rear end sounded quiet when I was driving it around. I have not used the tractor to know if that changed when loaded hard. I looked at the tranny through the belt pully gearbox opening last week and thought that every thing looked good, tight shafts and good gears. What is the most likely source of the parts and is there away to diagnose short of pulling the top deck off? Thanks, Mike S.

Owen Aaland · Mar 7, 2009

If you do not have any leakage into the brakes the most likely place for the bearing pieces to come from is an inner axle bearing. If you have a quite place to work on it you can usually hear the the problem by jacking up a rear wheel. Slowly turn the wheel and listen for the balls to drop as the go over the top of the inner race. With the separater missing the balls will all be together in a row. As you turn the axle they will roll up one side and then fall down the other side. You might also be able to hear a rumble as the axles and bull pinions are turned.

GordoSD · Mar 7, 2009

Owen's got it right. Inner axle bearing. You can replace it through the PTO.
Jack and determine which side is broken.
To repair pull the PTO. Then shim up the bull gear with appropriate wood wedge so it doesn't move when you remove the bolt that secures it on the shaft. Then pull the axle and housing and replace the bearing. Not a difficult repair.

Gordo

GordoSD · Mar 7, 2009

Owen's got it right. Inner axle bearing. You can replace it through the PTO.
Jack and determine which side is broken.
To repair pull the PTO. Then shim up the bull gear with appropriate wood wedge so it doesn't move when you remove the bolt that secures it on the shaft. Then pull the axle and housing and replace the bearing.
After repairing it would be a good idea to just add 10 gals of diesel and used oil, and drive it slowly around for a few minutes to see if there is any more junk in there and then flush. No need to contaminate brand new expensive HyTran.
Not a difficult repair.

Gordo

Anonymous-0 · Mar 7, 2009

It's also possible that somebody changed the inner axle bearing in the past, and never got all the pieces of the old one out of the case. I went through that on my M years ago. We had the deck off, one axle out, cleaned the whole case, and couldn't find a darn thing wrong with it. The shop boss at the local dealership told me that the pieces were probably from a previous failure.

randy hall · Mar 7, 2009

before you go to all the trouble of pulling an axle out. take the brakes off then the backing plate and pull the bull pinions out and see if their bearings are ok first. on a super the pinions will come right out unlike a straight m.

Mike Schwartz · Mar 7, 2009

I hope that will be the case. I will jack the tractor up and see if I can hear anything. I just redid the brakes and they were not oily, but I did not remove the backing plates. Will the bull pinion or axle feel loose at all or do the housings support them to well to tell if there is a bad bearing? I will dig into it today and report back, thanks, MIke S.

Icuby · Mar 7, 2009

I put a TA in a SMTA last summer,found the brg.was bad in the back of the top tranny shaft.

Mike Schwartz · Mar 7, 2009

I have pulled the IPTO unit and both pinion shafts out and the 4 pinion bearings and the two inner axle bearings all appear to be intact. Is there a bearing in the tranny that is as large as the ones in the rear end? The pieces have been floating around for a long time but other than grinding out the surface under the bull gears and chipping one bull gear tooth, I see no obviouse damage. I am wondering if it was repaired earlier and just not cleaned up. I have only found 3 balls, 2 half balls and about 1/3 of a cage. Please let me know what you think as I will wait for some further advise before going back together. Thanks, Mike S.

GordoSD · Mar 7, 2009

If you drive the tractor and hit one brake and then the other, you can find it. If you have a broken inner bearing the tractor will "lurch" and shake when you hit the brake for the broken axle.
If it drives around and you can;t feel a thing when you brake, it's as they say, "old stuff".
But I'd really try the jack and spin first. Get the tire going pretty good and hit the brake. If that inner bearing is all busted up, no way that axle isn't going to groan when you stop the weel quickly. I know this because I had to replace inner left on my SMTA.

Gordo

Gordo

Mike Schwartz · Mar 7, 2009

Gordo, I have the tractor up on jackstands and have went forward and back with both wheels and don't hear or feel anything. Looking through the hole in the bull gear i can see the inner bearingsand the cages are all intact. There is a little rust on some of the bearing and gear surfaces but I think that this is just a victim of limited use over the past 20 years.

SMTA rear end

Mike Schwartz

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Owen Aaland

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GordoSD

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GordoSD

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Anonymous-0

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randy hall

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Mike Schwartz

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Icuby

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Mike Schwartz

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GordoSD

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Mike Schwartz

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