I started my machine this morning it’s about 30 outside lows in 20s last nite I haven’t run it in 3 weeks . I let it warm up until water was around 150 just brought from idle to about 1/4 throttle just to move to barn and machine moved just fine let it sit and warm up some more then went to move it backed it up and turned it around at about 1/4 throttle started forward moved pretty normal speed then throttled it up and it slowed down at full throttle I’m mean it seemed like I moved the stick half way for speed ? It dint matter forward or revers slowed throttle back to 1/4 and moved it and the speed was back just not at full throttle ? Checked oil it’s fine only have 40 hrs since serviced all filters and changed all fluids using all cat fluids . Any ideas?
Fuel gelling up ? Or perhaps filter had some moisture that turned to ice ?
No engine runs fine the movement of machine slows up like when at 1/4 throttle it’s moving normall then go to full throttle it slows down ?
Does the engine go to and stay at full throttle and the transmission slows or is the engine bogging down?
Yes it stays full throttle and transmission slows down almost like putting an truck in low gear ?
Possibly a linkage issue? I would start with the easy things first, check and lube the linkage to make sure it's not frozen or worn out.
i agree. Also I'd suggest that you don't try to make any linkage adjustments at this stage. Just make sure everything is free and lubricated. I think this issue would benefit from some input from CMark...........
I have an old 963 that acts like that when it is cold. I have to run it 1/2 throttle till the oil warms up than it works correctly. I mostly only use it when its warm out so it doesn't bother much. I always figured the oil is a little to thick when its cold and causes it to bypass or something. Maybe the oil should be a lighter wt for colder operation.
My BBX series 953 does the same. I don't know if that's what constman6's loader is doing. When it's cold I'll let it warm up for a good 10-15 mins at low idle then idle up and go to work. The hydrostats are sluggish until the 10 WT is heated up. Doesn't do it in the warmer months.
Get all the systems thoroughly warmed up and report back if the symptoms remain unchanged.
Probably cavitating the charge pumps, if you lose charge pressure the servos can't move the swash plates against the centering springs.
I let it run idling for a good 2 hrs yesterday the trans felt warm so I tried to move it out of driveway back to a level place . It was moving and seemed normal at 1/4 throttle so I went to full throttle and it started slowing down then it stoped and won’t move at all . So I’m just going to have to leave it for now it’s only 12 here this morning . I wasn’t trying to use it this cold out was just trying to move it out of way to build a new garage . I did look at linkage it all did seem to be connected and operational . I don’t have my book here but I’m going home tomorrow so I will have to regroup this week . Thank everyone for in put I will get back with what I can find
Is there a test port for charge pump?
I have an ASV PT50 that had a similar issue maybe two winters ago.....may not apply to your situation, but I’ll pass it along just in case. Mine started and ran fine while warming up. After running it at speed for maybe 15 minutes (snow blowing), it started to lug. Did that a few times. Couldn’t find anything wrong. Brought it inside the garage and fired ip my kerosene turbo heater and aimed it under the ASV. Ran the heater for a good hour - got everything nice and warm like it was a summer day. That fixed the issue. Never had a problem after that. Have no clue what part was frozen/freezing up.
Hey thanks for commenting . You know I haven’t ran this before in the cold like it is it is pretty cold here it almost felt like a pressure release not seating when under full throttle but I don’t know if it has one on trans but the last few times a started it just to keep battery’s up I didn’t move it problem is I have no books or tools here at this house I will have to wait until I get back to shop . But the heater is a good idea I think I will bring one here and my concrete blankets if nothing else it will be warmer to work on . Thanks will let everyone know what I find
Could be the seals on the servo lines they are a metal ferruel and it will act like that when leaking
Ssems like it lost all pressure now still don’t have my manual are they under the cover ?
Yes they are but if you lost all pressure you have more problems do you know if you have 10 weight oil in the trans also I would put a gauge on the charge pump it has a port for it. I would try changing the filter again and make sure someone did not put a clean out filter on instead of the normal one
Yes it is the 10 weight I got all fluid from cat and filters . On the charge pump does it have one of those quick connect fittings on it ? I will have to see if cat has that so I can add to my gauge . I remember herring the pump whining when I would start to keep battery’s charged and would go away after a little while when oil would start thinning I would guess but that noise is gone and it wasn’t loud but I could here it .
Yes it has a quick coupler
Well after testing and reading I’m under the top cover of trans . It seems those seals are shot on tubes . I went to carter cat and they gave me prints which don’t look anything like what I found on it I will show a pick hopefully someone knows the terminology and part number . I can’t believe they can’t get me the right parts ?
Try supplying a Serial Number........
19z00250
I'd like Cmark's opinion but those tubes and fittings do not look like Cat parts to me. Can you post a photo of the tube as installed on the machine to give some perspective exactly where it fits.?
Are these any good I can take more if needed thx
These are the hydro trans tubes under the top that looks like a valve cover they go to under speed valve and servo .
I think they should be fine for identification purposes. The only thing that comes to mind is that the seals in the ends of the tubes are either part of the Tube Assembly and not listed separately in the Parts Manual, or are part of the fitting assembly into which the tube fits (the swivel nuts on the tube in your photo is) and again are not shown separately. I'm fairly sure what is just above the flange on the tube is a 3J-1907 but what appears to be the more complex seal in the end of the tube in your photo is not listed anywhere that I can see.
I have never seen a seal like this before it almost looks like a valve seal for a engine head ? And these don’t seem tight enough to hold any pressure at all . The guy that was at the cat parts dealer retired and the new people just don’t seem to know any more than I do .
From what I remember they look right to me
Hi Dave , when I got the new seals they are just green oring seals ? These things are more complex than that for sure here is a close up pick . Maybe they they are right and they messed up .
What Part Number of O-Ring seal did they sell to you.?
This may shed some light ......... a Service Mag from back in 1984 regarding correct assembly of this type of connector. Sorry the photo is not the best. Correct Assembly Of Connectors In Hydrostatic Transmission There have been problems of separation of some tubes and connector assemblies in the hydrostatic transmission for 943 and 953 Loaders. This separation will give a loss in oil flow. Wrong assembly of the connector assembly can cause this separation. The parts of the connector assembly must be assembled in exactly the same position and sequence as shown in the illustration. For example, the anchor, which is similar to a bevel washer, must be installed with the small diameter toward the end of tube as shown. If the anchor is installed in the wrong position it can permit a separation of the tube from the connector assembly. New Nut Assembly For Fittings In Hydrostatic Transmission A new 5P8752 Nut Assembly is now available for parts service. This new nut assembly is used on several different fittings in the hydrostatic transmission. The nut assembly permits the replacement of the nut, retainer, anchor, guide and seal in these fittings. Before, the complete fitting had to be ordered if one of these components was damaged. The 5P8752 Nut Assembly can be used for service of the 5P8547 Tee, 5P8548 Connector, 5P8549 Connector or 5P9036 Elbow.
The seals should be part number 8T9502. Those old ones look like the correct part. As per Nige's service mag, it's important to assemble them correctly. Torque is 15 +- 2 lbft.
Wow thanks Nige and Cmark . Heading there in morning I hope they have them . I will let everyone know how it works out thxs.
Thanks Chris. Here's another couple of titbits I found ........... one a Service Mag mentioning the 8T-9502 Part Number of seal becoming available for parts service. Previously you'd have to buy a complete connector to get one, as you would with the swivel nut mentioned above. The 2nd a Parts Manual listing from a different prefix of 943 that indicates (but does not show) the 8T-9502 seal. The 3G-9375 Lines gp is the same as used on the OP's machine. This is obviously from a machine produced after the seal was released for parts service.
As a side note. I've used a number of different types of compression fittings. Not this type though. The tube should freely sit in the fitting with out stress side to side in or out. If not hold it straight as best you can while tightening the fitting. First hand tighten the tube and fitting, then use a felt tip to mark the tube next to the nut. Then before tightening the fitting you then slide the tube back out a little. This will help to keep the ferrule’s/sealing ring's compression coming in from both sides. The taper on the fitting, and also the taper inside the nut. If you are having trouble with a fitting leaking it maybe the tube is jammed against the bottom of the fitting. If so try cutting off a little of the tube that sticks past the ferrule. Use a cutoff wheel or a hacksaw. Remove burrs inside and out and clean thoroughly. If it still leaks clean fitting and tubing with something like brake cleaner then use a little pipe dope or Permatex #2 on both sides of the feral. Don’t get the sealant inside the plumbing! Works the best if you can leave it dry for a couple days.
Thanks Nige I will show all that info to cat tomorrow hopefully get my parts . And put these reference numbers in my parts Manuel .
Thanks cat 977.
Well I got it all back together today it seemed more responsive and moved good at about 1/4 throttle pulled throttle all way open and it slowed down again went to revers same thing backed to where it was out of way stoped and went to go forward nothing . I’m trying to find a cat mechanics around here that has worked on these it isn’t easy even carter cat don’t want to work on it ? Not sure what to do next I guess I will get back in book tonight and start reading again maybe drop pan and drop trans oil pan to find that screen on charge pump pick up see if pan is dirty or anything filter was clean oil looks like new as it should .
You need Cmark. He’s the resident Cat hydrostatic loader expert.
Those seals were definitely leaking that made a big difference but when going full throttle and it slowing down then changing direction and it stopping makes no sense to me after about an hr or so if I restart it it will go again until I go to full throttle again ? Driving me crazy although that don’t take much now days .
First thing to check is the engine RPM at full throttle. It should be 2550+-60rpm. I've written a fair bit of prose on this subject here. Click on this link for further reading and if you still have any questions, don't hesitate to ask. https://letmegooglethat.com/?q=cmark+hydrostatic+site:HeavyEquipmentForums
also this one HeavyEquipmentForums
Hey Nige do you know the part number for the quick connect test ports the female end i need more to connect test hoses to trans on 943 Serial # 19Z00250 .
I think it is 6V-4144 (see below). I would stand corrected on that though. The male nipple that mates with it is P/N 6V-3966. Do you have the complete Test & Adjust procedure for the powertrain..?
Yes I keep reading them wow ! A lot there . The machine won’t move at all now so I figured start from scratch . It don’t seem broke the oil and filter were like new . I have a pan gasket for it was going to pull that but I thought I would wait until I could hook up all gages and run thru the test . I found a man that works on these in his shop but now I can’t even load it so I guess I will go it alone with the help of all you on here . Been reading a lot of what Clark sent me that brings a lot in focus.
I think it's wise to hold back and learn as much as you can on this machine. Maybe fix it yourself or before you give it to a 3rd party. You want to learn from your work. Also you want to get to learn what's B.S. or what's making sense and what's helping and what's not. Best of Luck
Well fixed one problem bleed brakes now it moves and way more reasons I’ve when moving from park to forward or revers . I warmed it up went and dug a little with it for about an hr but the speed thing hasn’t changed . It moves faster at low idle than at full throttle . I noticed the ends on the throttle linkage going to trans are worn . So now I’m thinking to pull top cover back off wondering if things under there are also worn ? I’ve read the book 4 times I still don’t feel comfortable changing any of the worn ends . I can get it loaded on truck now thinking on hauling it back to my shop and get my neighbor who also thinks the wear on those parts have moved it out of adjustment . Trying to find someone to haul it the last time it was 700 which ends up 7.00 a mile not sure if that’s good or not.