We have purchased a 963C SN: CAT0963CH2DS02162 with a little over 11,000 hours on it. The machine, we were told by the salesman, had 2 new drive motors installed within the last 1000 hours. We finally have put the teeth in the ground and low and behold, its got issues. The engine starts and runs well, but when put the machine to temperature and really work the machine we start seeing the machine track speed slow to a creep just as soon as you touch the implement controls. Before you move the boom or bucket, it runs strong pushing into a cut. No bogging down or anything audible to point to a motor issue. To get the machine back to normal speed you have to move the go stick back to neutral and then go back to moving. After a few hours of use the problem seemed to get worse, to the point where when tracking back to the shop and traveling up a short hill the machine would barely crawl up the short 2:1 slope. The issue occurs in both track speed modes. Machine has been parked until we can get gauges on the pumps. The other issue we found is that the engine has a fairly strong vibration at half throttle. Sometimes it will clear up if you move the throttle to 100% other times it wont. The engine doesn't shake at idle or generally if you go from idle to 100% quickly after warming up. Could this be a harmonic dampener issue or something between the engine and pumps? I was told that older 955L's had a biscuit between the engine and transmission and if it was worn would cause something similar to what were seeing on this machine. Could this be a possibility on this newer series machine?
All I can say is that is helpful is that the 955L does have 4 rubber pucks/biscuits between the motor and torque converter shafts to act as a flex coupling, though the tolerance for misalignment is very small. On a 955L you can remove the floor plate around the pedals and get your eyes on the flexible coupling to eye up the condition. Looking at the 963C cross section image found at the link below (it will open as a pdf document), it appears the motor is directly coupling to a hydro pump, so if that is the case you don't have a flexible coupling. https://www.google.com/url?sa=i&url...ved=0CAIQjRxqFwoTCOjBy8X05uwCFQAAAAAdAAAAABAD
Sounds like the engine may be losing speed. It should not go below 2200 rpm . Check it with the display on the dash and if necessary, verify that the dash is reading correctly using a phototach.
Other than they're both track loaders, not much in common between a 955 and a 963.
I have a third party mechanic checking out the machine today. I will ask if he has the phototach to perform the secondary check on the dash tach reading. He is also checking that the pressure were set correctly and adjusting if needed.
True. Thought they might have shared a commonality there.
Checking pressures is of secondary importance. If he knows these machines, carrying out the calibrations should be one of his first steps.
And for that he’ll need to know how to get into the various calibration sub-modes, in what order, and how to set each one up....
The mechanic through a friend he used to work with at the local Cat dealer has gotten access to a laptop with the service advisor software. Hope to have the mechanic come back out later this week to check the pressures.
I am hoping that the service advisor software will help him through this process. He’s a younger mechanic that just went independent. I’ll pass this information along.
I also forgot to mention that the engine was losing RPM based on the tach read out. He advised to change out filters and when he returns we’ll continue with the trouble shooting.
At the risk of repeating what's been said before, the sequence ought to be: - 1. Verify engine High Idle RPM (and see if it varies under load). A phototach plus the output from submode 18 can be used as a cross-check. 2. Check the calibrations of at least the basics - FYI there are no less than 28 calibration submodes. 3. See where 1 & 2 get you before thinknig about putting gauges on it. The laptop will be of limited help to him. This generation of machines tends to use the "old-fashioned" Click Box to do the calibrations. There is a thread on it in the Shop Talk section that might be of some help to him. It's been mentioned before with respect to calibrations, but it's not a job for the uninitiated. I suggest you tell him to read up throughly on SENR8314 before he even touches the machine.
How much does rpms drop? Case drain flow on drive motors when it's warm is one of first checks I do. drive pump failure is very common and if one bad the other is close.
Nige, I got on the machine and ran it today to get some readings off the in display tachometer and here is what I have: High Idle: 2250-2255 Tracking: 2150 with little variation beyond 10rpm or so depending on terrain your going over Dig Heavy: 2050 avg. never falling below 2000 Since the last post, I had all of the hydraulic oil filters changed out on the machine after we found some oil in one of the quick disconnect lines to the bucket had water in the oil. I found this strange because the oil in the tank is very clean, almost new if I had to say one way or the other. After we changed all of the hyd. filters the machine does not seem to be repeating the same symptoms that I described above? Could a dirty or otherwise contaminated filter have caused this issue? Makes me wonder if the previous owner had changed out the oil and the drive motors as we are told, why would the filters have not been changed?... Many questions seem to be cropping up with this loader. Regarding the rest of the bulleted items, the mechanic is coming back next week to continue with the checks. I have provided him with a copy of your recommendations. More updates to come. Thanks for your help.
Here are the readings I was getting of the in display tachometer: High Idle: 2250-2255 Tracking: 2150 with little variation beyond 10rpm or so depending on terrain your going over Dig Heavy: 2050 avg. never falling below 2000
Cmark, Following up on this post. I ran the machine today and wrote down the RPM readings i was seeing off the in display tachometer. here is what I have: High Idle: 2250-2255 Tracking: 2150 with little variation beyond 10rpm or so depending on terrain your going over Dig Heavy: 2050 avg. never falling below 2000
If he has any issues with the Procedure document SENR8314 let me know and I can download a copy. The only thing I can think of regarding "water in the oil" is that the filter(s) in the power train & implement side might well suffer from poor fluid flow rates if a significant amount of water was absorbed into the filter media.
So straight away that tells us you probably have an engine issue. High idle should be 2325+-50 RPM. First check that the throttle linkage isn't sticking anywhere and is letting the governor lever hit the stop screw. Especially check that this spring loaded gismo on top of the governor isn't seized. The throttle lever in the cab should activate a microswitch when moved to WOT. Also check that this is occurring.
As said before, rpm's should never drop below 2130+/-50 even in a double stall when both the power train and implements are loaded up. So you are fine in single stall when using only the powertrain but with the added load of the implements the engine falls on it's face and the computer reduces travel speed so the engine can recover. It can be throttle linkage out of adjustment, bad injector or seal, fuel pressure, fuel rack out of adjustment. Start with the easy stuff, linkage and air and fuel filters, turbocharger condition, boost leaks. then move on to check fuel pressure under load, air in fuel, fuel rack settings.
We’re going to start checking these items this coming week. Took the machine out to the new project we’re kicking off to help following up behind the timber crew to push up the slash for burning. The same problems with slow track speed etc. began to propagate again. Machine has been brought back to the shop for further diagnostics. We’ll start with these items.