Cat 963c two speed not working moves slow

[pittsburgh cat man]

Atta boy Nige Go to sub mode 19

 

[pittsburgh cat man]

also check sub mode 26,27 it will prob be in kpa 19 too

 

[Sbird]

In sub 19 reads reads 00000 at low idle park 0122 high idle park 2206 high idle full forward

 

[Sbird]

Sub 26 shows 0084 low idle park 0104 high idle park 1530 high idle full forward speed
And sub 27 0086 low idle park and 0118 high idle park and 1544 high idle forward

 

[pittsburgh cat man]

I think i screwed up on charge pressure I was thinking all the c s were the same but they are not check senr1834-11 Nige sent. stall test sheet need to crank charge to high side of spec even 430 would be fine

 

[Sbird]

I cranked charge pressure up to 430 still no change in speed got call back from cat been waiting all week for they shed some light said that they diagnosed machine couple months ago for previous owner they went through all steps we have and found same results we have and they concluded both pumps were weak and needs both pumps replaced that was their conclusion is it common for both to go at same time would there be way test pumps for sure just seems odd to me both go same time what are y’all’s thoughts

 

[1466IH]

I don't have near as much experience as either of the two that have been helping but in my experience usually if one goes they both do. If you decide to do anything with the pumps I very highly suggest following all of the hydraulic system clean up steps because whatever is going through your pumps is also going through the motors and if you do not service those along with the pumps they will push debris right through your brand new pumps. Have a machine identical to yours in the stop right now for that exact reason. They pulled pumps and had them repaired by a hydrostatic shop but they never touched the motors or any of the control system. They brought it here so we could calibrate and after it kept failing calibrations and operating horribly we called them back and got the full story

 

[pittsburgh cat man]

I'm not biting on both pumps being weak I guess we need to do a stall test you are going to need a 9000 pound gauge and a test line that will stand 7000 pounds you can do one side at a time and a gage on charge pressure use the stall test sheet in 2nd thing Nige sent watch what they say about holding it at full forward and full reverse and then neutral. one more thing if they just went thru this stuff and they had sis why wasn't the charge around 430 ??

 

[pittsburgh cat man]

I was just thinking lets do the calibrations again when you do min track speed turn it up till it's barely moving then try the rest of calibrations I was just wondering if it was turned so far down it would effect high speed?

 

[Sbird]

Sounds good I will try that tomorrow and see what I find I don’t get the weak pump deal it’s got ton power when moving it will push a mountain over but just at 2mph I know someone mentioned once that at level 3 was where pumps were fully stroked and motors take over well what signals motors to take over acts like that’s the problem it’s got ton power up to level three I even sent it down steep hill thinking if pumps are weak it would gain speed on steep downhill and it don’t it holds steady at 2 mph up and down steep hill

 

[Sbird]

I was just thinking lets do the calibrations again when you do min track speed turn it up till it's barely moving then try the rest of calibrations I was just wondering if it was turned so far down it would effect high speed?

Another side note cat also said about 3 months ago they seen same machine and diagnosed bad ecm then said lights and codes popping up so the customer said he would replace himself and I’m sure it’s not new may be refurbished has no yellow paint on it at all

 

[pittsburgh cat man]

Something is telling it to do what it is doing. I've been studying brake pedal being partly depressed causes motors to go to max angle witch is slow speed even if control and pumps are at max angle To get high speed pumps have to be at max angle and motors at min angle check pedal and make sure it is up the whole way maybe a little penetrating oil would help. Ecms aren't painted new or OR ,seeing how it has the latest software in it, it sounds like it was replaced

 

[Cmark]

Back in post #116, you said pilot pressure at max fwd and rev was 200psi. This is about right. I have a feeling it may be just the motors that aren't destroking. I ask again, does it look like the motor adjustments have been tampered with?
Whatever the answer though, we still need to be getting a reading from the speed sensors to adjust things properly.

 

[Sbird]

Back in post #116, you said pilot pressure at max fwd and rev was 200psi. This is about right. I have a feeling it may be just the motors that aren't destroking. I ask again, does it look like the motor adjustments have been tampered with?
Whatever the answer though, we still need to be getting a reading from the speed sensors to adjust things properly.
View attachment 336394

I can’t see any signs of the motors being messed with recently anyway I’m sure the belly pans haven’t been opened on it very recent there was 4 inches of dirt mud built up on them when I dropped them so no obvious signs of recent activity there and my question on speed display I read that level 1and 2 will display 00 for speed until you reach speed above that so wonder if I’m going too slow to register speed at this point I will retest the harness again today I know sensors are good I swapped them out with the engine sensor and got good rpm reading with both so would have to be in wiring if there is problem there or ecm ! My question is I know need reading to adjust top speed for sure but got to get machine moving faster than 1.9-2 mph first so if it’s not reading speed can that cause slow speed problem

 

[Sbird]

Been trying all morning get the hydraulics up to temp for stall test can’t get them climb above 62 degree C and have moticed when you apply brakes while moving right track will stop but left track continues to move will go in circles until release brake

 

[pittsburgh cat man]

Get yourself self some where you have room put it in stall pull it in gear and see what it does the new book says only hold for 5 seconds in full forward

 

[Sbird]

Get yourself self some where you have room put it in stall pull it in gear and see what it does the new book says only hold for 5 seconds in full forward

Got it warmed up as book said and hooked gauges high idle with park brake applied as stated in sub 20 put gauges on charge pressure 435 right forward 0 left forward 0 right reverse 0 left reverse 0 so skipped to stall test transmission only part high file full forward charge dropped to 400 still zero on all other ports

 

[Sbird]

I’m guessing should have been checking these pressures at sinc valve not on same block as charge pressure valve I hooked there and am getting readings now

 

[pittsburgh cat man]

Don’t push the brake when you stall it

 

[Sbird]