Cat 963c two speed not working moves slow

[Sbird]

Do this one side at a time.

• Disconnect the signal hose at the motor. Plug the hose. Leave the fitting at the motor open.
• Put a good accurate pressure gauge on the forward signal pressure tap for the side you are adjusting.
• Run the engine at high idle and monitor signal pressure and track speed.
• Move the FNR control slowly forwards. Watch the track speed and stop at the exact moment the track speed stops increasing. At this point the pump is fully upstroked. Record the signal pressure and track speed. Return the FNR to neutral.
• Stop the engine and reconnect the signal hose.
• Back off the motor adjusting locknut and adjuster a few turns.
• Run the engine and move the FNR until you get the same signal pressure that you recorded earlier. Your track speed should also be the same as earlier.
• Start to slowly turn in the adjuster. Watch the track speed closely and stop the adjustment when the track speed JUST begins to increase. At this point, the motor is beginning to destroke to give you your upper range of speed. If you overshoot on the adjustment, back it out and start again. Adjust on the rise.

You may have to try a couple of times to get it right. If you get a dead band or a sudden speed increase part way through the FNR travel, try again.

View attachment 336611

Perfect thank you I will try first thing tomorrow when my help gets here and see what I get figured out

 

[Cmark]

Another thought. It may help to tighten up the friction clutch on the FNR lever to give you more precise control.

 

[Sbird]

Ok we have done exactly what you have directed on the left side motor and turned adjustment in both directions with no result we did gain signal pressure but no speed gain at all

 

[Cmark]

So you turned in the big adjusting screw circled in red and gained signal pressure but no speed? That shouldn't happen. Signal pressure is controlled by the ECM/solenoid valves. Are all the hoses connected to the correct fittings? Something strange is going on.

 

[Sbird]

Yes adjusted the big screw you had circled in red went in about three turns no speed change so backed back out to previous setting and backed off three more turns and went back in again and still no change besides he seen signal pressure rise like 75 lbs hoses all look just like picture you sent hooked in same spots but I didn’t adjust the clutch up on the direction lever so possibly vibration of machine might have moved it little it doesn’t seem loose or floppy so I didn’t touch it

 

[Cmark]

That's definitely not right. Can you trace the signal hoses back from the motors? Each one should go back to a tee fitting with a 3 wire pressure sensor.

 

[pittsburgh cat man]

I still think it's a control problem. since from what i can see in parts brake and steering sensors are the same pull the little panel under the pedals and swap plugs with brake and i think right steer pedal and see if that makes you any speed

 

[Sbird]

That's definitely not right. Can you trace the signal hoses back from the motors? Each one should go back to a tee fitting with a 3 wire pressure sensor.

Yes that’s exactly how they run I’m really thinking pressure change had to be from lever moving in cab

 

[Sbird]

I still think it's a control problem. since from what i can see in parts brake and steering sensors are the same pull the little panel under the pedals and swap plugs with brake and i think right steer pedal and see if that makes you any speed

Ok will try

 

[Sbird]

I still think it's a control problem. since from what i can see in parts brake and steering sensors are the same pull the little panel under the pedals and swap plugs with brake and i think right steer pedal and see if that makes you any speed

Tried it and no differents just sits at 3.58 and won’t turn up

 

[Sbird]

I’m my simple mind it’s something keeping motors at maximum displacement ! Because when signal line is disconnected I’m getting the exact same speed as when it’s connected and getting good signal pressure but no speed gain at all just stuck at 33 percent of speed so if signal pressure is good is it something in the motor control that is stuck ?

 

[pittsburgh cat man]

Rats I was hopeful we would get lucky. I still bothered by it effecting both sides if it was some thing stuck in motor both motors would have to be stuck the same

 

[Sbird]

Just to see what happens I turned the maximum angle stop screw in 1 turn on the motors just to see and it gained .1 on speed so tells me the port plate is sitting at max angle all time

 

[Sbird]

Rats I was hopeful we would get lucky. I still bothered by it effecting both sides if it was some thing stuck in motor both motors would have to be stuck the same

Yes I was holding my breath and fingers crossed while trying but no luck lol

 

[Sbird]

I will throw this out there again signal pressure left motor high idle 176 in park and 2172 full forward and signal pressure right motor is 158 high idle park and 2050 in full forward is that in spec

 

[Cmark]

If those figures are kPa, then they're in the ballpark. More than enough to make the motor destroke.

 

[Sbird]

If those figures are kPa, then they're in the ballpark. More than enough to make the motor destroke.

Yes kpa that’s what the dash displays them in I think

 

[Cmark]

It really isn't that complicated. The motors get charge pressure down one of the small lines and signal pressure down the other. The charge pressure is what moves the swash plate, the signal pressure against the spring pressure shifts the control spool and the spool directs charge pressure to either side of the swashplate piston.

Next question. Do you have charge pressure at the motors? You will need to tee a gauge into the line.
(I have a gut feeling this might be a blue-cap issue)

 

[pittsburgh cat man]

Check and see if you have hoses between x1 and x2 on your pumps

 

[Sbird]

Check and see if you have hoses between x1 and x2 on your pumps

Yes both of them