JD 260 Skid Steer Drive issues

SFischer · Jan 13, 2015

I have a John Deere 260 series II skid steer that is turning in to a money pit to get a drive issue fixed. I am hoping to get some advise on what the next step could be to the solution as I am sick of disassembling this thing and would rather not do it any more then I have to.
The problem:
In low speed the right side drive control would knock when being used under any kind of load. In high the knocking would get worse and the right side drive would fail to move the machine at all. We removed the right side drive motor and had it rebuilt but after assembly the problem still existed, not to the same severity but was still there non the less. The machine is still short of power on the right side and knocks under load.
Description on "KNock"
The sound it makes when under a load and the right drive control lever is pushed forward in full... it resembles the sound of a gear being stripped out with the frequency of the knock increasing with forward force placed on the drive lever. Each knock is distinguishable, as you could count them if you wanted, not a constant sound.

Hopefully someone with more knowledge on this topic can help. Already 4k+ in to the problem and am trying to avoid taking it to a dealer and paying that kind of $$

oldnslo · Jan 13, 2015

Is there a chance the drive sprockets are worn enough that the drive chains are slipping? I believe that would cause a hard mechanical knock. Not sure what components in the drive motor would cause this noise.

SFischer · Jan 13, 2015

The sprockets and chains look A1. One concern was if the splines of the drive sprockets on the wheel side were stripping over. Seamed unlikely but it was what one mechanics thought.
I no longer believe the problem is the drive motor since it has a fresh rebuild in it. We thought it was because the seal in the motor was bad and releasing pressure in to the chain case. That's when the hydraulic place we took it to said it was pretty tore up inside.

Also I just cut the old hydraulic filter apart and found metal flakes and shavings all over it which has me thinking something in the pump has gone out and the filings took the drive motor out before getting caught in the filter... it makes sense to me but I am not sure if the pump has separate systems for each side? wouldn't the lack of power be on both sides of the drive?

TreeSupplier · Jan 15, 2015

Few questions:
Does your machine have dry or wet brakes?
Did you just remove the drive motor or drive motor and brake assembly?
Do you know how to determine your drive chain slack to see if it needs adjustment?

The Drive motor is a closed loop, meaning the oil is constantly recirculated in that loop only. With fresh Hyd oil entering as pressure increases and oil leaves via the drain case line. Both drive motors are on their own closed loop. All other hydraulic cylinders on the machine are open loop meaning they are constantly recirculated through the Hyd tank and filter.
The drive motor drain case line has an encased filter that needs to be checked and cleaned from time to time especially after drive motor replacement or repair. This will catch any metal, o ring or seal debris from the drive motor before it reaches and contaminates the pumps. It is located at the back of each and attached to the brake housing. This filter will plug and disable the drive motor which will cause it to build too much pressure, burst the seal in the brake housing between the drive and brake housing filling your dry brakes with hyd oil. The the blockage will cause heat and cook the o rings in the drive motor.

A simple step to determine where the knock is coming from:
Raise and block the machine so all wheels are off the ground (do not use concrete cinder blocks). Start the machine and have some one push the controls and locate the knock. If you think it is the wheel sprocket spline gears it is easy to look at. First remove your wheels form that side, unbolt the 8 bolts on the axle housing, pull the axle housing off. It is a bit odd shaped to pull off. I slide them back but not off the bolts and use a rope in a loop, feed it through the two top axle housing bolt holes, loop it back into its self kinda like a noose and slide my hand in the loop, lift up with the other hand supporting the outer axle housing and slide off. Some people use a strap and choke the axle housing. Either way be sure to have a clean place to set it first.