First post here; been a lurker for awhile. I appreciate all the great info I've read here! My 963 track loader has 3500 hours, and has (as far as I know) been correctly maintained all along. I bought it from a retiring contractor, and use it for ranch work (grading, dozing, filling, etc). Last time I operated it to move a few dozen loads of dirt, I noticed that the machine was moving slower at full throttle, and I found that the hydrostatic sight glass showed brownish cloudy fluid . I changed the fluid with a good quality Napa C-2-approved fluid, and drained the filter housing per book, and replaced the filter. The machine still won't move at full-throttle, but moves fine at half-throttle. In reading over some other posts here, I'm thinking that the new filter may be clogged, as I don't believe I got all the old fluid out via the drain plug (specs show it holds 18 gals, and it was "full", but I got 13 gallons or so). Now basically it behaves the same as before; it moves strong and pushes hard, but only until half throttle. My question is; is there more to the procedure in changing the hydrostatic oil and filter, than is shown in the Cat 963 maintenance manual? Often there are tips & tricks that they don't include, as they're assuming that a Cat mechanic will already know those things, but I'm just an amateur with common sense and moderate hydraulic and mechanical experience. Additionally, am I going to damage the pumps if I try to move it in this condition? Thanks for any input on this, and I humbly apologize for my first post being a series of questions. Usually I try to offer help to others first, but in this case, I'm the newbie... Charles
You are on the right track thinking the filter is clogged. I think you should get a Donaldson filter, need to get you the number.The new Cat filters are finer and require too much warmup time. The Donaldson is like the original filter. You also need 10 oil, anything else causes the problem you have. You are running on the Underspeed Override valve when you throttle down. Later Bob
I agree with Bob about the 10W oil. However I'm not sure about the filter. If the filter's plugging the oil is "dirty", I'd personally keep changing the filter until it doesn't plug. There are a load of high dollar parts in that system and dirty oil can crap any one of them out really quickly.
Nige, I suspect the filters aren't that dirty. We always used a fire retardent fluid filter, not the 4J6064 because it was finer but the world got running ahead of us ol sodbusters. Now the standard filters are finer than the ones we used and the Donaldson was a good fit for cleaning the oil and the machine working at lower temps. Later Bob
Bob, I take your point 100% and you may well be right in this case and others as well. What gets me because I work in Contamination Control as part of my job is that we analyze new oil straight from the oil company and it doesn't meet required cleanliness standards. In cases like that it's no wonder new filters plug up in short order, they're not taking out the products of wear in the system - they're cleaning the oil that the oil company couldn't be bothered to properly clean in the first place before they put it in the barrel........ The fire-retardant filter..? Ah-ha the good old 4T-3132. Haven't seen that number in a while. I'd use 132-8876 to clean that system out, although it might need the inner spring in the filter bypass valve replacing to get the best out of the element and make sure it didn't plug prematurely. Interesting to note that the Parts Manual calls for the 132-8876 right off the bat. If that's the Part Number the OP is using and it's plugging rapidly try a 1R-0741, that's the modern-day direct replacement for 4J-6064
Been there done that Nige, on the new oil blowing the ISOcount. But I hear from a credable person that te Raw Stock oil from the tank is the base oil for everything. When we order a tanker full they add the additives as they load it and they are suspended in transit and as loaded into our tanks. I can say that I have tested brand new oil and it didn't pass but after working the machine for a few hours and found that same oil retested fine once the additives became part of the solution not the emulsion. I hope this is true( A man believes what he wants to believe ) Later Bob
Bob, just a thought. note the title - Cat 963B hydrostat slippage after fluid contaminated - "I found that the hydrostatic sight glass showed brownish cloudy fluid" says the OP. I suspect the fluid is still contaminated to a certain extent even after changing the oil and that's most likely a reason why the newly-installed filter has plugged. I've heard the story about additives "settling" and have found nothing to back it up based on my experience. It's like the urban myth "If you use too fine a filter for engine oil you run the risk of the filter trapping the complex chain molecules of the additives because they are so large to pass through it". Check out this photo. This is a recirculating filter on an oil storage tank (TO-4 SAE30) after operating continuously for 24 hours after the oil company dropped a fresh load of 5,000 gallons of oil in the tank. We wanted to prove a point to the oil company so the filters where changed after the new oil was dicharged into the tank and before the recirculating pump was started. You tell me what you see - additives or **** ....??
Thank you for the replies! It sounds like I might be OK if I get the fluid & filter problems fixed correctly. The new filter is a Napa replacement, which with all the spare stuff I got when we bought the machine. It was in a sealed box, thus clean. The old one showed no particles or sludge, but I did get a small amount of possible water from the filter housing drain. Maybe as little as an ounce, but any is BAD. I assume that some water will show up from normal condensation over time, and I hope the machine has been designed to let water settle to the bottom of the sump. I think I know how the fluid got contaminated: I am guilty of causing it by not listening to my own intuition, and using a gallon or so of fluid to top it off several months ago, which I think may have been less-than-cleanest. I heard a sudden gurgle when the last bit went down the funnel, which I now bet was some condensate water :thumbdown: . The fluid stayed nice & clear for the next few times I operated it, but that's the only explanation I can come up with for the brownish color. Not foamy, but but the color of engine oil when a head gasket leaks a little water into the oil. Just wondering, if I call out a mechanic, is there a machine that could do a total flush; similar to what they use on car transmissions by disconnecting a cooling line or other low-side hose, and injecting new fluid while collecting the old? If not, I guess I'll have to change it several more times to be safe... I intend to call one anyway to look the machine over before we need it for a fairly big grading job this summer (to make 4 acres plantable). I'm probably going to hire a pro operator, and I don't want to be foolish and risk damage and waste paid operator time, to save a buck not having a mechanic's once-over and missing things. On the other hand, no reason to pay a mechanic for dirty labor work that I can do (such as to re-change oil a few times if that's the best thing to do) ; especially if I caused it be needed. Charles
Charles, I think I would pull the plug(7/8"hex) out of the top cover of the HPCU and look for any creamy sludge. If you don't find any change the filter again as per manual, let it warm up and try operating. Nige those additives look like Nard Narvels to me. Later Bob
Let me jump in if i may. Should check pressure differential across filter. With these symptoms i usually find a leaking oil line under top. Cover going to the underspeed valve. Leaking pressure oil back into case making it look cloudy and the sight gauges tend to look dark after age. With throttle in full position oil wont build enough pressure to raise valve. A misadjusted throttle linkage can do the same.
Excuse the bump, but believe it or not, I still haven't solved this issue, so I hope I'm OK to bump the old thread so as to preserve the history of it. I changed the fluid twice, and am confident that there is no issue with foul oil or filter. We used the machine for a 5-day filling & compacting job at our ranch, and it worked OK, but the (experienced) operator said it wasn't quite moving like it should; low speed and sluggish. He replaced the fuel filter, and that seemed to help, but now fast-forward to now (2 years)... I start it and move it just to keep it lubed, and not to let anything seize up. As of earlier this year, it has stopped moving all but just trying to nudge a foot or so forward or reverse, and it acts like there is a total loss of hydraulic pressure to the final drives (both hydro motors behave the same) . I have a mechanic scheduled to come out Monday and have a look at it, but I though I'd post here and see if anyone has any thoughts on this problem, and/or anything I might do or check first. I don't have the experience on these things to know whether things like the throttle linkage or the transmission lever linkage are working and set right. This problem has definitely slowly developed; not a sudden failure. Thank you all again for the advice last time, and Thank you in advance for any ideas, and I'll follow up here with what I find out on Monday (9/28).
Since you park it for long times the center speed control pedal might be seizing up. Take a bar and pry it up as hard as you can and try it. Come on back,ASAP. Later Bob
Expanding on Bob's suggestion above it might be worthwhile to lift the floor plates and free off/lubricate every single one of the linkages from all the pedals to the steering/brake controls ........ and there are quite a few of them.
Hi Members; my 973 has started to give similar problem- moves good at low throttle but loses travel at full. Started after it kept blowing oring seals at the speed and sync valves. On opening valve body the mechanic found 2 of spools stuck. Since reassembling the unit works fine for 2 days then blows another seal. I had been warned about using good filters and oil, and I had started to suspect my choice of oil. Tomorrow we will change out oil and filter, plus pull down the sync, speed valve to reinspect. Peter
Rather than complicate matters I suggest you start a new thread if your machine continues to experience problems. There is only one oil specification that I can see and that is a good quality 10W. It doesn't have to be Cat oil but neither should it be the stuff you buy at the local 7-11 either ......