Rear wheels not pulling

[Steiner5]

I have been playing around with a B series TC and got it stuck. This is when I found out that only one of the tires on the front axle was spinning. I tried engaging the differential lock and still neither of the rear tires would spin. I checked and it has not thrown any codes. Any ideas????

Thanks...
Rick

 

[Egon]

There is a differential on the front. Does the differential lock work? Does the tractor move in two wheel drive?

 

[Steiner5]

Egon,

Yes, I am aware there is a differential on the front also. However, it was my understanding (certainly could be wrong) that the differential lock only applied to the rear axle. The TC moves fine when just driving around. No noticeable problems. You asked "does the tractor move in two wheel drive". I didn't know there was any way to put a TC into two wheel drive. I thought it was always in 4WD.

 

[goeduck]

I do not know if we are talking about a Kubota B series or a Boomer TC. That said, both my 4 WD Kubotas are rear lock only, not front.

 

[Steiner5]

I guess I should have been more specific. This is happening to a 2005 B series ToolCat 5600.

 

[Steiner5]

Today I did a test. I jacked up the front axle such that neither of the front wheels were touching the ground. Both rear wheels were still on the ground. I started the machine and attempted to gently drive it both forward and backwards. Only the front tires rotated but the machine never moved. So that verified to me that there is very little if any torque being transferred to the rear axle. I also tried this with the differential lock activated and got the same results.

 

[Dakota Kid]

Check your rear CV drive axles, sounds like you snapped one off.
P.S. don't worry about your rear differential or rear drive motor, there working as they should or the machine would be dead in its tracks right where you got stuck.

 

[Egon]

Egon,

Yes, I am aware there is a differential on the front also. However, it was my understanding (certainly could be wrong) that the differential lock only applied to the rear axle. The TC moves fine when just driving around. No noticeable problems. You asked "does the tractor move in two wheel drive". I didn't know there was any way to put a TC into two wheel drive. I thought it was always in 4WD.

Ahhh - I was unfamiliar with the type of machine but I see you found a solution!

 

[Jabonee]

Sounds like you have an axel issue. Try jacking up front of TC with a jack that rolls. Start the engine and lower the armrest to release the brakes. See if you can push the TC. If you can something has failed in the rear axel. :thumbsup:

 

[ruffdog]

On a G series Toolcat, there are 2 transaxles, front/rear, that are driven by a hydraulic motor that is driven by fluid. The TA consists of a bunch of straight-cut reduction gears to a differential center section. Each side axle is driven off each side of this center diff section. Are you getting hyd flow to your transaxle motor? Does the motor function? Are any of the reduction gears broke or stripped of teeth? Is the diff damaged? Is one axle broke or stripped so all of the power is going to the freewheeling side?

First, with the front tires off the ground and the 'cat shut off, can you rotated either front wheel? While holding one wheel, rotate other wheel? Second, I would put the 'cat up on stands and while running and armrest down and in F/R (brakes released), how does the diff and gears feel when rotating the tires?

 

[Steiner5]

Thanks to everyone for your input. Now I have several things to try/test tomorrow. I will let you know what I find.

 

[Steiner5]

OK, more data. I jacked the vehicle up and supported it with 4 jack stands on level concrete. When I rotated by hand one of the front tires, the other one rotated in the opposite direction. This is what I expected for an open differential. I performed this same test on one of the rear tires and got the same results. Both times the tires rotated freely without any unusual sounds. I then started the vehicle with the arm rest lowered and put it in forward. I had someone watching and all 4 tires rotated in the forward direction. I then had them hold one of the front tires and he was able to stop it from rotating relatively easily and the other tire rotated forward. Once again this is what I expected as all of the torque was being transmitted to the wheel with the least resistance. This was also performed on the rear axle and we got the same results. I then had him try to hold one of the rear wheels while I engaged the differential lock. He was not able to prevent it from rotating which to me says the differential lock is working. I then lowered the rear axle to the ground with the front axle still supported in the air on a floor jack. I then tried to drive the vehicle forward. The vehicle made a very slight movement in the forward direction with the front axle turning in the air in the forward direction. I then put the vehicle in reverse and it did the same thing. A very slight movement was noticed in the reverse direction and the front axle spun as it should in the reverse direction.

It seems as though everything mechanically is fine but for some reason the rear axle is not supplying any appreciable amount of torque. If anyone has any thoughts or other tests I should perform, I would be very grateful.

Thanks...
Rick

 

[ruffdog]

Looking at G series manual again:

No drive on one axle= 1..check for drive codes 2..a hydrostatic drive motor has damage 3..the brake is not releasing 4..a hydrostatic pump has damage (belt driven off engine, has test port for pressure) 5..a replenishing valve not seating (four of them on pump)

 

[Steiner5]

Ruffdog,

Thanks, I just found that same list for my B-series in the service manual although it also includes speed sensor not working. There are not any error codes. I assume there isn't any issue with the brake not releasing since I was able to rotate each wheel by hand. As far as the hydrostatic pump having damage, I assume it is OK since the front axle is capable of moving the vehicle around unless there are two hydrostatic pumps, one for each axle. I thought there is only one hydrostatic pump but I could be wrong.

As for the replenishing valve, I do see there are four of them. The service manual mentions that if you do not have drive on one axle it might be one of the replenishing valves is not seating. I see the 4 valves in the manual on the pump but it just shows an overall picture of the pump but it isn't in the vehicle. I am not certain where the hydrostatic pump is located relative to the vehicle. Has anyone ever checked the replenishing valves? Just looking for some general information in regards to what to expect. Can I remove them without draining all of the hydraulic fluid?

 

[ruffdog]

There is one pump, belt driven, on engine. I'm at the limit of helping as I have not tore into them myself. I wish you luck.

 

[ruffdog]

https://www.plowsite.com/threads/toolcat-owners-read-this.67305/

 

[Jabonee]

Early model TCs had issues with drive motors failing. Your symptoms don't really match. There is a lot of splined shafts in that axel. Possibly one is wiped off. Maybe drain the axel lube and take a good look. :confused3:

 

[timm9]

If you were experiencing a drive motor failure you would see a code for a plugged hydraulic filter and a gradual loss of power. Some years back I had a similar issue with the rear axle not engaging and the unit was actually dragging the rear along. Turns out it was a major rear axle failure that was the result the unit being stuck and the driver slamming the unit back and forth trying to extricate himself until he spun the rear axle.

 

[Steiner5]

Thanks for the thoughts and ideas. It will be this weekend before I have a chance to dig deeper but I will let you know what I find.

 

[Steiner5]

One possible cause of one axle not supplying torque as per the manual is a replenishing valve is not seating properly. Well it turns out there are 4 replenishing valves. Two of them are relatively easy to access. Simply drop the oil pan skid plate and they are easy to access. I removed both of them and checked the springs, shims and seat. Everything was clean and in good order. According to the manual, to access the other two you need to remove the engine. Not something I want to tackle especially as I'm not certain this is the cause of the problem. After checking the two that I could access from the bottom I put everything back together, jacked up the front end and with a floor jack to see if the rear wheels would drive the vehicle either forward or backward. It did the exact same thing which is the vehicle makes a very slight movement but only the front wheels which are in the air turn. When I am doing this the engine was just idling as I didn't want the vehicle to lurch off of the floor jack. I started thinking maybe I needed a little more RPM to develop the necessary hydraulic pressure. So I revved the engine to about half throttle and now the vehicle will move both forward and backwards. Bottom line I think I simply made a rookie mistake and didn't have the RPM of the engine high enough. When I previously got it stuck I was simply trying to connect a bucket on the front and also didn't have the RPM very high. Just thought I would document this so someone doesn't make the same mistake.