963 Transmission Question

[garbhead]

Looks like a good website...I have a 963 that runs good except some time if I idle it down, and the back up it won't move..feels like the forward/reverse stick is disconnected(no resistance)....you can just keep moving it alternating forward/reverse and it will eventually take off....if I keep it idled up, it will run all day without stalling..I have talked to Caterpillar about it, and of course they say , bring it in, we can pull the transmission and check it out....I don't think it is anything major, just annoying as its been doing this for 4-5 years...anyone have any ideas? thanks

 

[StanRAUUS]

Assuming when you fire up the machine with cold oil, the machine engages frw/reverse, but after the oil heats up and the machine is idled down frw/reverse won’t engage 1] trans pump suction line could be sucking air 2] trans pump worn] 3 excessive directional clutch oil seal leakage

Check the suction line clamps/seals - check trans pump pressures – check pressure @ trans control valve. If the internal clutch seals are worn-out then trans will have to be removed for repairs.

 

[lgammon]

ours did that, our mechanic worked on it a time or two. he got it fixed. it wasn't to big of a bill, i am pretty sure he did it in the machine.

 

[overworked]

You really need to check the trans pressures, make sure to drain filter housing before u remove the old filter, when cold, does your track speed slow as you raise the rpm's ? When you idle down your trans pilot pressure drops below a set pressure witch is the same as brake release pressure, I can't remember correct terms. Try raising rpm, push direction control toword windshild to reset pressure and then try to move maching, let me know .

 

[outlaw6755]

I have a 1982 year model 963 that i bought because the guy said that i only needed a valve body so i replaced that and also new charge pump and it still will not move and i have not heard anyone say anything good about these transmissions so i bought another trans but not sure if it's any good and also i noticed that i have no hyd pressure on the line on the left side coming up to the valve body so can someone please tell me what i'm doing wrong? Or lead me in the rite direction so maybe i can get this thing moving thanks

 

[Nige]

can someone please tell me what i'm doing wrong?

Stop loading the poarts cannon and do some testing maybe.?

1982 year model 963 that i bought because the guy said that i only needed a valve body

And you believed him..?

Need input from @Cmark on this one. Meantime please start by posting your Serial Number because it makes it easier to look up technical information regarding your particular machine.

 

[outlaw6755]

Thanks and my serial number is 29S00868

 

[Dave Neubert]

I have had the metal lines going to the servos leak at the connections I replaced the connecting fittings and it fixed the problem

 

[Welder Dave]

I have a 1982 year model 963 that i bought because the guy said that i only needed a valve body so i replaced that and also new charge pump and it still will not move and i have not heard anyone say anything good about these transmissions so i bought another trans but not sure if it's any good and also i noticed that i have no hyd pressure on the line on the left side coming up to the valve body so can someone please tell me what i'm doing wrong? Or lead me in the rite direction so maybe i can get this thing moving thanks

You always have to be leery when a seller makes it sound like a minor repair is needed. If it was such a minor (low cost) repair why didn't they fix it and sell the machine for more money??

 

[mudober]

I find it normal on everyone I ever ran. There just not meant to be idled down and operated that way. I seen a guy smash a light plant once with a 963 he was on a slight slope idled down and it freerolled forward. Best to run it full throttle when trying to inch up on something.

 

[Welder Dave]

Most hydrostatic machines work best at full throttle. Running at low RPM is hard on them and can cause damage. Some like early Cat skid steers had a throttle pedal because they were very difficult to control for precision movement at high RPM's. I think the newer machines have much better control. My old 94 skid steer I could pick up eggs at full throttle. I'd have to spend a bunch of time in a joystick machine but I really like having 2 levers for totally independent control of each set of wheels, especially in tight area's.

 

[outlaw6755]

Hey Dave thanks for the info and yes i have changed the lines and the rubber sleeve looking o rings still the same but i did have a guy tell me that it could be air locked and it makes since because i have no hyd pressure on the bottom part of the transmission

 

[outlaw6755]

And also with it running i can hear the transmission making a whining noise

 

[Nige]

And also with it running i can hear the transmission making a whining noise

Have you cut apart a transmission filter recently to look for sparklies in it.?

 

[skyking1]

sparklies

you make it sound so festive.

 

[outlaw6755]

No not yet but i will .....This transmission has no hyd pressure on the bottom i crack the lines with it running and no pressure at all

 

[Nige]

Here is a good VIDEO showing how to do it. I know it's an engine oil filter in the video but the principle remains exactly the same for a hystat transmission filter.

 

[outlaw6755]

Nige no metal in the filter the fluid is as clean as new what are the symptoms of a bad torque converter?

 

[Nige]

what are the symptoms of a bad torque converter?

Your 963 doesn't have a torque converter......

Attached a document that gives the details of how the drive system operates.

 

[outlaw6755]

Nige no metal in the filter the fluid is as clean as new what are the symptoms of a bad torque converter?

Your 963 doesn't have a torque converter......

Attached a document that gives the details of how the drive system operates.

Thank you Nige you have been so much help!!