Is there anyone on here that can help with some Clark 28000 4spd transmission questions. Thanks
Model and serial number? and what kind of issues are you having? What application?
Amen; my all seeing eye is a little bloodshot today. give us a hint about your problem
Model 12.1HR28428-501 SN yusa138099. In a Fiatallis FR120.2 Wheel Loader. I think about a 93 model. Only has 1200 hrs. Seems to be only 4th gear in F and R. Neutral works fine. All solenoids are getting voltage when they are supposed to. From the information I currently have - the speed solenoids 1,2, and 3 are used in gears 1,2,3 - 4th is when none of these are energized. Filter seemed very clean. Fluid looks good. I am sure I am forgetting something... Pressure gauge in dash is in green but I have not tested anything with a test gauge because I am not sure where to test. Loader failed when the operator pushed into a pit and when he tried to back out - could not.
Maybe not worded right. When in F or R - there is no gear available except the one it is in, which seems to be 4th - this is in all gear selections.
From what I remember you are correct. The gauge in the dash should be sufficient to troubleshoot. Watch the gauge, start in neutral.....select F1, then watch the gauge as you select 2-3-4. The gauge should do a slight flicker (small drop in pressure through each selection of gear range) and then recover. Do the same in reverse. The pressure gauge should read the same pressure through each range. If you see the quick flicker in the gauge through each gear, that tells me your electrical shifter is probably working. I would then check each coil for continuity between the 2 wires. There is also a clutch dump valve in the transmission control vale but I believe it dumps every gear, including 4th. It is usually operated by the left brake pedal, electrically through a switch on the treadle valve. Check these and get back with us.
Check the grounds for the solenoids, sounds like you may have lost the ground strap for the transmission. jumper a wire from the solenoid grounds to the battery ground and see what happens.
There is no flicker in the pressure, I know for sure. The solenoids are getting 24v when they are supposed to get it - there are 5 solenoids - F, R, 1, 2, 3. According to the Fiat manual and all of my testing, This is how it works: When in neutral - either at the shifter or with the neutral selection switch or with the brake pedal neutral kickout turned on or if the electric park brake switch is on - the F and R solenoids are electrically disabled.. When in F the F solenoid is energized When in R the R solenoid is energized When in first solenoids 1,2, and 3 - known as the speed solenoids are all energized. When in second, solenoids 2 and 3 are energized. When in third, solenoid 3 is energized When in Netral - the speed solenoids are still energized just no F or R is. All of this works. I have tested this many times, literally from the shifter to the solenoids. Even had the machine on blocks - no jerk, or pressure guage flutter or change in wheel speed when twisting the gear selector on the shifter. I removed coil 1 and held a screwdriver in it - very strong magnetic force. Since this coil is working - unless it has a stuck spool in its valve - then something would have changed when it opened it valve during transmission operation while the machine is on blocks - nothing happened - I used a Power Probe to energize that coil during operation and nothing happens. If the spools in under each solenoid are stuck from debris - then they would have all had to get stuck at the same time without sticking F and R. Please remember - the machine moves on level ground or down hill - I fell sure that is in 4th gear because of this and that 4th is the absence of fluid being controlled by the speed solenoids. I theorize the something is preventing the fluid channels that send pressure to the appropriate clutches, from getting pressure. Or what about the clutch that is controlled by solenoid 3, which is used in all gears 1,2,3. Could it have a blown seal? If so, wouldn't the pressure drop in the entire system when fluid is sent to it. Or could fluid still work the F or R and the 4 (or as it is called on the drawings"Hi") clutch. I have spent about 40 hours on all this testing - mostly due to the fact that the F solenoid showed no voltage on the very first day - in hind sight - I think the guy I had in the seat that day did not have it in F. In closing - I think my focus need to be - what could fail and allow fluid to be directed to the F, R, and Hi, but not the Low, 2 and 3? Thanks again Any input is appreciated.
BTW - I checked the grounds during all of this - I use a Power Probe Hook to do all this testing. If your not familiar with what a Power Probe is, they are great, look at online. The Hook can handle up to48V. They tell you if a the probe is ground, hot or nothing everytime you touch something. Ground are all good. Thanks
Check your charge pump pressures. Bob
The hose going to the gauge on the dash is coming from the top of the pump. It shows well into the green. Have not installed a different gauge to do a pressure test because I don't know which port to try next and-- would the forward, reverse and high clutches be able to work if I had low pressure? Going to the shop right now to pull the sump screen and possibly start pulling valves and the valve body - no one I have talked to seems to be able to tell me what ports might be good locations to press test. There seems to be unknowns on this electric valve body. I'll let you know.
You may have confused yourself or maybe you confused me. In any powershift transmission I have ever encountered in any given gear you will have two clutches engaged, one directional and one speed, and that applies specifically to the 2800 Clark transmission. Never will three speed clutches be engaged in any gear.
If I can learn how to scan in my wiring diagram, I will attach the chart that is in the corner that has three columns - shifter position, wires energized, solenoids. First line is Shifter position F1, wires energized - T6, T4, T5, T9 - Solenoid F,1,2,3 Second line - F2 - T6,T5,T9 - F,2,3 Third Line - F3 - T6,T9 - F,3 Fourth Line - F4 - T6 - F Neutral is the same 1,2,3 solenoid and corresponding wire numbers plus a wire labeled AS which goes to power the start relay so the mashine will start when in neutral only. F and R solenoid not energized but the twisting gear selector still sends voltage to the solenoids. Reverse is the same as Forward but the F solenoid is replace with the R solenoid which is wire T7. All the wire numbers, and functions I have teste at many different places many times - they function as the wiring diagram and manual say they should. Drained the fluid and pulled the sump screen - screen was very clean - if I could post a picture I would - almost nothing on the screen - what was there mostly looked like very small pieces of silicon, but I don't think it was. Nothing magnetic was on the screen. To me it looked like stuff that could have been in the original casting when assembled. Maybe 20 pcs in all. But I pulled a dumb dumb - the high pressure filter I pulled the other night was the brake system filter - it was so clean and so irrelevant. It is very hard to see all the hoses under the cab. Even though the info I have shows a high pressure filter housing - my filter is a spin on - AND the damn thing is a Clark brand with a date of 98 - and I found a SN on the bucket with a 98 date on it so I feel sure that the machine is a 98 and the filter was original. Books say the filter has a bypass in it - wonder if the filter finally plugged, bypass opened, let some trash by and stuck a valve in the valve body and or the modulator body that I now have a picture of. Maybe a valve that lets fluid to the 123 clutches? Unless someone sends me on a different path, next is removing the valve bode and modulator plates to do exploratory surgery and see if I can find some stuck or clogged valves or orifices
You lost me. Your past the electronics and into the knuckle busting. Good luck
Found a weak solenoid coil. Must not have gotten a good reading on the resistance early on or could see the meter good. I found a company who only works on Dana Clark Spicer Hurth Transmissions - Hydro-Mechanical Systems in Westville, New Jersey. Rocky , the service mgr, knew exactly what my transmission was and how the valve body was configured. Told me that 1 of the 3 speed spools not moving not working can cause all three not to work. That changed the way I looked at it, so I started with the solenoid valve that is used the most - number 3 - when I went to remove the coil it was stuck on the valve body tube - finally got it off and it was deformed from heat. Got one on the way - will follow up when installed.
Rocky must be one of us old guys. There is a lot that isn't in the books. Did not know about the interaction. FYI when using a Power Probe or a aux supply and not too much noise you can hear the spools click in if they are working. Hope the new unit gets you going. Let us know.
Yep!!!!! That fixed it.!!! Now I get to go thru all fluids - transmission of course is already done. After I got it working I drove it up and down the road, took out large cedar tree (I waged war on them years ago here in the northern end of the TX Hill Country) works as it should. The machine has switches (I call them proximity switches but I think they are called hall effect sensors) to kick out the hydraulics, when the bucket is level and when it is raised all the way - they even work - amazing for a 20 year old. There were three switches with rubber boots that were still intact - one for the kick down option that allows you to shift from 1st to 2nd with a button on the joystick, One switch for the kick out option that puts the trans in neutral when you apply the brake, and one that test the lights on the dummy light panel. I thought the switches would have to be replaced because the were froze. Turns out the rubber used for the boots was so hard and thick that they could not move - cut off and all three function. The turn signal had the same rubber for the boot at the base of it - unfortunately none of its functions work. There is a trigger switch on the joystick that I think is some kind of reverser, but it does nothing. I say it is a reverser because there is a reverser relay in the wiring that is operated by a switch in the joystick, but there is no picture of the switch and it shows to be optional. The relay is there, and functions with the gear shifter, but I have not taken the joystick apart to see the this switch is wired into the circuit. If anyone has any input on how it may be designed to function?... Other than maintenance, I have to reseal the parking brake cylinder. It leaks during movement, but not at the end of its stroke. I have another question that I may post as a new thread - what fluid is used in the differentials. The old FR160 that I used to work on for a customer, would grab when you turned it on a hard surface. After much research, found that a friction modifier was needed for a limited slip type clutch. After locating some strait friction modifier from our oil supplier, ($375 per 2 quart bottle, if I remember correctly) the problem was solved. I hope this isn't the case with this loader. Barely took any modifier - I was told to add a few ounces at a time until the problem went away. I think we had a lot left over but if the machine was maintained correctly it would have been use on future maintenance. Thanks to everyone for their input and interest in helping me with this problem.
BTW- laycobeau, Hydro Mechanical Systems only works on Dana Spicer Clark, and IIRC they said for the last 42 years. I asked them if they would work on an Allison or ZF and he promptly replied with a simple "no". My life has turned me into a jack of all trades type person, but it seems that every job I have had working for a payroll check has been one that was leading me down a path of being a specialist in some unique way. So I like it when I find the guy or company that is truly a specialist and is good at it. Not many can make it without branching out. I know that as a self employeed person I would not have made it through some tough times if I had not been the jack of all trades. The older I get, the more my jack of all trades bites me in the ***. One week I am trying to fix something in an electrical circuit the next its a overheating problem that other mechanics can't solve. It seems to take more time to switch gears these days, then when I get in gear I end up having to go a different direction. It does keep me from being bored and I have turned downed a lot of payroll jobs over the years because I know I get bored easy. I hope this thread gives them some business.
thanks for you input and mechanic skill , im having the same problem with my 140.2 fiat loader, i was leaning towards a bad coil or bad valve, but this will definitely help me fix mine tomorrow ! its stuck in 3rd gear..
If I get a email I watch these threads. Let me know if you need more help. I did not look at everything I wrote, so I might repeat myself. I worked on a FR140 years ago. There were 2 diode blocks under the joystick area that look like relays. One of the diodes inside one of the diode blocks was bad causing stuck in 3 if I remember correctly. Don't get the diode blocks and relays positions mixed up. I can tell you how to check the diodes if you need help
If it gets too complicated I can give you my number
Where are you in texas?
Hey there, wow didnt think on the diodes .... but im located outside winnsboro tx , 9036295381, but yes your expertise would be greatly appreciated lol , i got your forum messages printed out, gonna bring them to the shop monday
yes please send your number if you dont mind sir
2546315511 - I could tell which ones diode blocks because they were lighter than a normal relay. I popped the cover off and they had 3 diodes soldered to the 5 terminals in a certain configuration. I think both blocks were the same. I have seen this on one other peice of equipment since then but I cant remember which one - may have been a manlift. I tested the diodes and when I found one that showed bad I snipped it out and tested isolated. Back then radio shack was barely hanging on and I went to the closest one - 37 cents and a little soldering and problem solved. I think that machine had 5 solenoids on the valve body. It was a ZF i think. My 120 is a clark. I have a chart that shows which solenoids should be energized in which gear. It might get you there faster if you had that chart. Unless you find a failed component like a diode, you might just be guessing at what is going on without the chart. That 140 years ago was rode hard for years to come - they retired it because the main bucket pins were about to wear through the arms. No telling how many loads of sand it dug out of a private pit. The trans never wore out. My phone is sketchy where I live so calling is ok, texting is more reliable and then I can come get close to my booster and call back. I live outside Hamilton tx in Pottsville. Not knowing your skill level ... let me know if you need specifics on diodes BTW I know my 120 has a similar set up with diodes but I have not had to dive into it. Best I remember, the 140 showed them on a page with a diagram but not on the main schematic - they were related to the kick down and reverser buttons on the joystick - I have learned that most people don't know what those function are either. They work perfect on my 120 and the owner never knew how to use them. I will be on hear a while longer tonight
I will go to the shop and check the diodes Tomorow , when i bought the loader the buttons on loader joystick didnt work, and the torque lock buttom, and the kick down button, the local shop rebuilt the wireing harness last week already, they used to be a fiat dealer in the 80s 90s , will have to check the coil as well by the solenoids. this 140.2 got a clark transmission , bought it with 4000 hrs , came from bonham county , gave $6500 for it , dam good machine , using it on my dairy for loads of work. has 5700 hours now, everything tight, always greased and air filter cleaned every fuel up... but will keep you posted on progress, and if we get passed the testing scenario .. thanks
Funny that your a dairyman. I work on generators and manlifts for a few dairys around here. The manilfts are usually Thomson Dairy Services in Dublin. Looking at your ID is why I asked where you were. Actually I have a customer that is a "Big Dutchman" that does not pay well enough for me to continue to work for. We are not crossways, but he knows that when I have to come to the house to get my check after 2 weeks of no answer phone calls, things are not well. When I asked where you were the other day, I was worried you might be him. He has at least 1 old fiat and he loves them. Sounds like you got a good machine. The company where I bought my solenoid could probably get you the chart I was talking about. If you are familiar with Thomson - he has sent me to a few generator jobs, but as myself not as a sub. One of them was in Canton over a year ago - I think he is installing a carousel for that dairy right now. Let me know...
Yes i know that guy in canton, they finished the carousel , nice people , just took on alot of debt.... I like to collect of big dozers that are abandoned , and other old equipment, fiat and allis are my number ones ... I know thompson dairy service, talked to the older service tech few times, but they are far away from me. Have you met Mickhael Parker ? he subs for thompson from time to time. also there are few shady dutch farmers that way and to stephenville , i dont associate with them . But the guy thats hard to pay you , also he being a cheap ass lol , like to know his name so i can rag on him next time i see him
Not a chance on giving his name. Around here the Dutch seem to have all married other Dutch and the next gerations have grown. I can't keep track of who is married to whom. I like the guy to talk to. Just don't like the business practices. I grew up in Glen Rose and worked in the welding trade around stephenville during school. Almost all dairy related - in a shop and some portable - not structures. I learned a lot about the industry and swore I would never be in it. Now I am about 50 percent. But I am lazy and tired and refuse to be pushed to work all night. So I can't be in it anymore than I am right now. The generators are always neglected. Everyone was on a push after the big freeze. Then they went right back to their old ways. The Generators sit, never started and never even looked at. They seemed to all have gone and bought oversized gensets used. They cannot even be loaded if the whole dairy was running on them in the heat of summer. I can't help but stay out of it sometimes, they don't like what I have to say. Then I try to train them on fuel management which is something I have a lot of experience in. Only one of my customers has done anything about that. Last year we had a freeze that got some of them, but not enough to change. I will get off my soap box. We do have a robot dairy outside of Stephenville that Thomson put in. They test ran it on the generator and found that it would not work. Called the guy (not me ) that helped them with the install - he could not figure it out. Then they got the power company to bring an oscilloscope to watch it run. But he called me to come observe to see if I saw anything. I am not that good in my opinion, but I am always amazed at what others don't know. I watched as the other guy adjusted the voltage with a dial on the old unit, while we waited on the power company to show. The voltage "wiggled" as he adjusted- I saw it, but he thought it was just a lag. Not in my experience - he got a new potentiometer (voltage adjustment dial) problem solved. That diary cannot afford problems - and by the way, that is the wierdest bunch of cows I have ever seen. They all act like they are stoned and happy. About your loader - what would have caused switches to go bad and a wiring harness? Any thoughts? Those shifters are hard to find in my experience. That is why I want my kick down and reverser buttons to work. I rarely use my shifter. I leave it in F2 and use the buttons. Takes a while to get used to, but that is how they were designed to be used. I was at a rock quarry a year ago. The guy loading me was have trouble with his shifter because it was wore out - it was an Hitachi but newer than my fiat. I asked if he knew the buttons function. I had to show him. He was grinning from ear to ear. If he had known them before, his shifter would not be wore out. I will try to keep my phone handy tomorrow. Today I was too greasy to handle it everytime it made a sound.
What should charge pump pressures & flow be on a Clark 28000 6 speed?
Look up Hydro-Mechanical, Westville NJ - they helped me on mine, but it was back in 2018.
Thanks-I looked them up, and the shop there is helping-thanks again!
It is nice to know that I could help. Thanks for the reply