Kubota bx23 shimies in forward and reverse

[Rickb57]

I have 2004 BX23 (I bought new)with 802 hours. When I start out from a dead stop and push the foot petal hard to go forward the tractor has a very noticable viberation or shimmie in both high and low. The front end loader and backhoe works fine, I used the FL to move a lot of snow this winter.

I took it to the dealer and he had it for 4 weeks and he said they can't find out whats causing the tractor to act like it is.

They checked pressures in various spots and said the hydraulic pressure was ok. Has anyone experienced this?

Thanks
Rick

 

[Rfisher7381]

Do you know the service history on the unit? As a starting point it may be worth changing the HST fluid, filter, and cleaning the screen.

 

[davrow]

Shimmy in a car is a tire related issue.

Did you run a front tire into a stump and bend something? Check them for alignment (per your owners manual). Are the lug nuts tight?

I'm guessing here.

 

[Rickb57]

I changed the motor oil and transmission as suggested. I always use HST in the transmission and recommended Kubota engine oil in the motor.

When I changed the transmisson fluid the oil was crystal clear with nothing in the screen. I changed the transmisson fluid thinking there was something in the screen causing the problem but it was clean.

 

[Recoveryhill]

I have 2004 BX23 (I bought new)with 802 hours. When I start out from a dead stop and push the foot petal hard to go forward the tractor has a very noticable viberation or shimmie in both high and low.

Shimmy: shaking, esp. abnormal vibration of the wheels of a motor vehicle

A true shimmy takes some speed to occur and you state that yours does this as it begins to move. I'll take "vibration" as a better description although I understand how difficult it is to define a particular problem. One thing I can bet you though is that if the tractor has a noticeable vibration when you move, something is not right.

My observations:

The dealer had it for four weeks and couldn't isolate the problem could translate that he had it sitting around for three weeks, four days and six hours before he looked at it and couldn't come up with a quick and serviceable answer. I'm not saying that's the fact but the length of time he had it means nothing.

"When I start out from a dead stop and push the foot pedal hard to go......" That seems to be an unusual way of operating a hydro transmission. The statement caused me to think how I operate mine and possibly other than repetitive loader work, in low range at a reasonable RPM, I don't start off depressing the treadle all the way. Could doing so have created a problem? Darned if I know but the control pedal is not, as you are aware, similar to a gas pedal. It controls torque and speed, less of one, more of the other.

Were it my machine and the vibration was sufficient to get my attention, I would look for a problem with running gear, U-Joints, final drive gears, brakes, lug nuts, clutch, something, anything downstream of the actual pump and transmission.

Finally, back to the dealer: If I had a "bad" vibration and a Kubota dealer couldn't figure it out, I'd probably be looking for a next Kubota dealer. Usually living with something like this instead of fixing it only leads to a bigger bill, down the road. In your case, if it's annoying but not severe, I'd consider living with it to see if it gets worse which may make a diagnosis easier.

Here's hoping you find it and it doesn't cost you a bundle to correct.

 

[Rfisher7381]

Can you provide greater detail regarding symptoms. You may get a few more responses. Any change between 2wd and 4wd? Might try raising rear wheels off ground in 2wd and observe how HST behaves (vibration/noise/?)

 

[oldnslo]

Does the vibration stop once the tractor is up to speed?

 

[Rickb57]

Recoveryhill your reply is very much appriciated. Your comment about the dealer having it 4 weeks and not his priority is probably spot on. I agree with your description that my problem is more of viberation than a shimmy. The viberation is not as noticable when I slowly push on the treadle in both forward and reverse, it's more noticable if I push the treadle a little harder. I am going to hold off taking it to the dealer today to try a few more things and will let you know the outcome. Thanks again for your comments

 

[Rickb57]

Rfisher7381, thank you for replying to my post. The viberation is noticable in both 4 and 2 wheel drive. I am going to the shop in a little while and try lifting the rear wheels off the ground to see how the HST acts as you suggested. I will let you know if I find anything unusual. Thanks again.

 

[Bluegill2]

What trans fluid did you put in it? These HST tractors run much better with Kubota SUDT2. Known fact.

 

[Rickb57]

I used super UDT fluid as required by Kubota. I jacked up the back of the tractor and it didn't seem to make noise like it does under when driving the tractor. It seems to have enogh pressure because I can lift the tractor off the ground using the fel and backhoe. I did notice that when driving the tractor up a 30 degree slope it makes more noise when extra power is needed, especially when in high . I also notice the rear tires seem to viberate, almost feels like air got into the hydraulic system. I always checked the HST fluid level and never had to add any fluid. Also worth mentioning is the noise subsides when i get to top speed in both high and low range on flat ground. If I am in high range at half throttle and slowly push on the trendle to go forward the viberation makes the whole tractor viberate.

 

[CHDinCT]

Do you per chance have a Bro-Tek skid plate installed? I had somewhat similar symptoms when I reinstalled my skid plate and over torqued the hander bolts. Thought my HST was broken but I noticed it made no unusual noises if I ran it when up on jack stands. Removing and reinstalling fixed it. Just a thought.

 

[Rfisher7381]

OP, did you resolve this yet?

 

[Recoveryhill]

I did notice that when driving the tractor up a 30 degree slope it makes more noise when extra power is needed, especially when in high .

Not making light of your issue but I make more noise when going up a 30 degree slope too! Don't do anything close to that in hi range, would be my advice.

I really think that you're going to need some professional help with your issue. If you don't have another Kubota dealer option there must be a number of crack heavy equipment mechanics in your area. Someone with intimate knowledge of drive systems could probably narrow down the problem in short order. Sounds like you need an educated guess and that's were an experienced mechanic could be of help. Scout around for a traveling Farm Equipment or Construction Equipment mechanic that can bring a rig to your place and take a look.

 

[Rickb57]

Its at the dealer now, I'm just waiting for the $$$estimate. Thanks to all that replied to my post. I will let all know the outcome when it's fixed

 

[Recoveryhill]

Good luck with it. I for one would be interested in what you find.

 

[CoveredWagon]

I am about fed up with Kubota dealers too! They had my BX24 for more than a week...charged me $70 and said they couldn't duplicate my problem. That was 4 years ago! After working for a while, my BX24 will not back up!

Now, I am tearing into my transmission and relief valves myself. What an experience (for a dedicated NON-Mechanic!) I suspect the reverse relief valve was incorrect from the MFG! Pressure tests for the relief valves are way below specs.

 

[BXpanded]

Sounds like one of the tires might be slipping on the rim. Mark the rims and tires and try it.

 

[workinallthetime]

vibrations are diagnosed by order, 1st order being the slowest rotating to 3rd order being the fast rotating. 1st being engine 3rd being tires. this is a way to organize the diag process, figure out what is turning at speed that causes the vibration and correct.
the process can be a little tricky and dangerous so be careful