Ker-Chunk in L4330 rear end during/after tight turn

[JonBarleycorn]

Hello,

My 2003 Kubota L4330 Hydrostat 402 hours has begun to make a ker-chunk sound in the past day or so and I am trying to isolate the cause.
It seems to occur mainly when I am in a tight turn or have just come out of one. This afternoon I noticed I did not hear/feel it as I drove into position and made a tight right turn on level ground in 2WD. As I backed out I could hear a chunking sound as I backed straight, after exiting the turn. It would occur with less than a full rear wheel rotation, perhaps every 1/4 to 1/2 rotation.
It seems loudest on the right rear, but I thought I could also hear it coming from left rear.
I tried depressing the brake to see if that made a difference, which it did not.
The main thing that made a difference was driving it straight for perhaps 100'.
It does it going forward also, it just happens I was backing more AFTER the turn. I tred going straight after making a tight turn and it made the sound then also. I noticed once or twice it made a noticeable squeak, as if metal on meatl were occuring.
Any help in diagnosing would be appreciated.
As I am right at a service interval to change the hydraulic fluid I hope to combine both of these repairs/maintenace.

Thanks!

[Hooked_on_HP]

Have you checked to see if your differential lock is stuck ingaged?
Bill

[carpenter383]

I would check to see if the diff lock is partially engaged like Hooked on HP said.
Also you might be able to get a better idea of whats going on if you jack the rear end up and spin the rear wheels by hand without the tractor running. Use a stethescope or screwdriver to try and pinpoint where the noise is coming from.

[JonBarleycorn]

Originally Posted by carpenter383

I would check to see if the diff lock is partially engaged like Hooked on HP said.
Also you might be able to get a better idea of whats going on if you jack the rear end up and spin the rear wheels by hand without the tractor running. Use a stethescope or screwdriver to try and pinpoint where the noise is coming from.

One of my first thoughts was the diff lock, which does not seem to be the case. As you probably know, it takes some effort to hold down the diff lock pedal, and it does appear ro disengage as usual when I release the pedal.

I'll try lifting the rear tomorrow and listening. Judging from the metallic squeak that I heard just before parking it today, I am not overly optimistic.

Thanks folks for your input!

[kevinj]

Originally Posted by JonBarleycorn

One of my first thoughts was the diff lock, which does not seem to be the case. As you probably know, it takes some effort to hold down the diff lock pedal, and it does appear ro disengage as usual when I release the pedal.

I'll try lifting the rear tomorrow and listening. Judging from the metallic squeak that I heard just before parking it today, I am not overly optimistic.

Thanks folks for your input!

Are you sure the wheels are tight??

[AndyMA]

If I was you I would get it looked at pronto. Any driving you do will only make it more $$. I needed ring and pinion in my Ford 2120 about 15 years ago and it was $1600+. I can imagine how many thousands a rear differential on a new tractor is these days. It may not be the differential, but some outer gears or bearings but you need to get it looked at before you use it anymore.

Andy

[Wheatland KB]

Perhaps you could drain a cup or two of fluid real quick like and look for metal particles. I hope it turns out OK for you!

[powerstroke444e]

Check the wheels and the wheel dishes (the disk that you can move to change the wheel spacing) I would give 10-1 that is the problem. Check every bolt and stud you will be amazed the noise they make when they come loose.

[JonBarleycorn]

Originally Posted by powerstroke444e

Check the wheels and the wheel dishes (the disk that you can move to change the wheel spacing) I would give 10-1 that is the problem. Check every bolt and stud you will be amazed the noise they make when they come loose.

Well, if you had money to place on your 10-1, you should have. You were spot on. The loosest lug nuts were on the right side, where I was hearing the most noise.
What a sigh of relief! A quick and cheap repair, 160 ft lbs later.

Thanks!

[JonBarleycorn]

Originally Posted by kevinj

Are you sure the wheels are tight??

I am now!!