Anyone know the ohms specs for the transmission solenoids on the control valve in the back. They have two wires that go into them from the harness. Serial is 2ZK03342. Am having issues with 2n 3rd 6th not shifting going forward but everything works in reverse. Been told them solenoids become faulty and can cause shifting issues.
The 9W-2739 Transmission Solenoid Valve coil has a resistance of 31 +/- 3 ohms. The common factor between 2nd, 3rd, & 6th speed forward is #2 clutch. Those particular transmission forward speeds are the only ones that use that clutch (no reverse speed uses it). See the diagram below. The plate #13 gives a list of the clutches that are engaged in any particular transmission gear. There are eight clutches in total. The test port for #2 clutch is the one that is circled on the right. I am not 100% sure but I think the solenoid valve for it is the one circled on the left side of the diagram. If not it is the one immediately to the left of it. As a first step try interchanging the solenoid valve for #2 clutch for any other solenoid valve (they are all identical) in the transmission and see if the problem of failing to engage 2nd, 3rd, & 6th speed forward moves from those speeds to a different 3 speeds in the transmission. If it does the solenoid valve is defective and needs to be replaced. If it does not you have a problem inside the transmission with #2 clutch.
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Swapped out number 2 solenoids and the one across it still no change. All solenoids also within specs. Checked screen and oil looks good no debris of clutches or metal. Can transmission speed sensor cause this also?
Do you know how much pressure I should have at pressure port circled when blade on in neutral position. Or when shifted in 2nd or any of the other faulty gears.
To do a pressure check you have to remove the differential drive shaft. If you engage 2nd, 3rd, or 6th gear with the engine at low idle speed and the brakes applied you should measure between 327 & 355psi at the test port for #2 clutch.
so does the differential drive shaft need to be removed or can you just apply the brakes with engine at low idle and shift into 2nd 3rd and 6th. If I am not getting the pressure of 327-355psi would it be likely that their is a clutch problem in the number 2 clutch slipping?
Theoretically if you engage 2nd gear at low idle and release the inching pedal with the brakes applied the engine will stall. If it doesn't then it would appear that #2 clutch is slipping. What pressure are you measuring at the test port?
If you want to shortcut removing the drive shaft, you can lift the wheels off the ground with the ripper. However then obviously the wheels will be turning during the test. Use this technique at your own risk.
I will report back on Monday what pressure I get. Thanks
Turned on blade and it worked in 2nd gear for a little bit then quit again. Anyone know if both the wires that go onto the #2 clutch solenoid are hot or both ground when blade on? Didn't have quick connect for pressure port but I think a have a faulty wire some where. Does anyone know were the wires from the clutch #2 solenoid run to?
Sounds like you need an electrical schematic. Drop me a PM with your email address.
Hi Lewis 12,normally if you have electrical problems the fault light in the dash should be a light, however this is not true for all faults especially high resistance in the wiring or solenoid driver faults from with in the ECM with the key on select the gear that is at fault you should be able to measure 24VDC at the solenoids engaged for that clutch ,don't use the frame as the return for your meter ,use the wires at the solenoids also there is a method to retrieve the active and logged fault codes without any special equipment here is a break down of the circuit that may help you
hi ,if you find you have 24VDC at the solenoids remove the complete modulating valve and swap with another clutch station
Mark is the 24vdc checked with the 2 wire connector plugged into solenoids. Or do i unplug the 2wire plug and check it coming from harness side. Because engine turned off i do get i believe 5vdc at all the 2 wire connectors solenoids unplugged. That's just telling me my wires from harness are good
The 24V DC is with the solenoid connected to the harness. If you disconnect the solenoid it will register an open circuit diagnostic code. Do you have any probes that you can either poke through the insulation on the wires or slide down the outside of the wire into the back of the connector for the solenoid..? If you want the Electrical Schematic for your machine just drop me a PM.
Yes schematic would be good. [email protected]
Okay anyone know any ways to trouble shoot the transmission control module were you shift your gears. All my transmission solenoids within specs even swapped out 2nd gear solenoid with valve and no change. Getting 5 vdc at the wire harness engine side with it unplugged from transmission solenoids. Gears sometimes work but then 2nd 3rd and 6 stop working.
Lewis, you're coming at this the from the wrong direction. The fact that you lose 2nd, 3rd, & 6th speeds points to the solenoid valve for #2 clutch is not working all the time because as you posted previously sometimes those transmission gears work and sometimes they don't. There are only 3 possible reasons for this and you have already eliminated one of them - the solenoid coil, by swapping it with another one but the problem stayed where it was. The other possibilities are:- 1. The mechanical part of the #2 solenoid valve could have an intermittent fault. If you have not already done it yet try interchanging the complete solenoid valve from #2 clutch station to a different location and see if anything changes. 2. You have an intermittent wire harness break somewhere between the Power Train ECM and the transmission control valve. The only way to find the fault is to locate all the harness connectors between the two components and disconnect every one of them. I don't have the Electrical Schematic in front of me right now but you need to identify the wire numbers that feed and return the voltage from the ECM to the #2 solenoid and using a digital multimeter to check the continuity of those wires in each section while someone else pulls that section of harness every which way to try to open up the broken wire. Once you have checked each section separately then start connecting the sections up one by one repeating the "pull test" each time you connect something. This is especially true of the connectors themselves. A corroded pin or one that is not 100% fully installed will also cause an open circuit, so give the connectors a good pull while testing for continuity. I'm pretty sure that you will find the fault somewhere in that section of wire harness.
especially check the harness through the articulation area this is always a suspect area due to flexing and all the hard ware that passes through this area Mark
Also I should have pointed out that to engage any particular gear in the transmission requires 3 clutches to be engaged. Your symptoms only point to a problem with one specific clutch - #2. Therefore it is highly unlikely (pretty much impossible TBH) for a problem in the transmission control selector in the cab to produce your specific symptoms.
I have a problem with my machine..it moves and stopped,now no gear is moving again...what can possibly cause that.
Potentially many things can cause it. What machine model is it.? Serial Number.? What have you looked at so far.?
The machine is caterpillar grader 140H,so far I checked for broken cable and found one cable broken.The cable was replaced and the machine moved for about 500 meters and stopped again and no gear was moving.we later re arrange the position of the solenoid and now only third gear for forward and reverse is working.
Was there ever a resolution to this concern? I am having the same problem. No 2nd, 3rd or 6th forward gears. I have zero PSI on clutch #2 port with tandems raised in the air in 2nd or 3rd gear at idle as well as only 5V at solenoid. tried swapping solenoids and plungers no change. will check wiring in the morning just wanted to double check. If i have only 5V at solenoid it indicates an open?
Please can you provide some more information. 1. Is your machine also a 140H.? Serial Number.? 2. Have you checked the oil for a burnt smell and inspected the transmission suction screen to rule out the possibillity of a mechanical problem.? 3. Do you have an electrical schematic.? You're probably going to need one. 4. When you say "solenoids and plungers" I assume you mean that you swapped the entire solenoid valve assemblies between clutches, not simply the coils.? Try reading through this THREAD , especially in regard to harness testing options (test light vs multimeter). It may give you some ideas.
Thank you for the reply Nige, the Machine # CAT0140HAAPM01458 - I have aces to CAT SiS for diagrams however not crazy about the website. - when back probing the solenoid connector with the machine running and in 2nd gear using a multi meter in only get 4.5-5.0V - I will try my 24V test light when I check the CKT from ECM to solenoid. -Yes I swapped the electrical portion first and then the plunger portion second with no change. Also bench tested coil and i was able to energize it and get a magnetic charge. -Fluid is a little dirty it could use a service but doesn't smell burnt. I am trying to rule out the controls before I determine the tranny is at fault. Due to the nature of the failure.
TBH the first thing I would suggest is to drop the oil into a clean container (don't dump it at this point - you can always put it back again to continue testing) then pull the screens, there are two of them, and inspect them for burned up clutch friction material. You need to rule out the possibility of a mechnical clutch failure before moving on to the electrical/electronic system. I just sent you an electrical schematic. Check your message inbox.
What voltage do you get across the other two solenoids that should also be energized with the selection of that partiuclar speed in the transmission.?
Check what amperage your test light consumes. Some of them are only of the order of 0.5A. You need something between 3-5A to sufficiently load any circuit just to make sure there is not a wire hanging on by a thread somewhere.
When checking all 3 of the solenoids that are activated in 2nd gear i get 4.5V on #2 and 23.5V on #4  when looking at the wiring diagram it shows 2 different resistance specifications for the different solenoids #2 is 8.5ohms and #4 & #7 are 31ohms double checked them with my meter they are with in spec. just not sure about the voltage being split like that but it does make sense base on the different ohm spec. I use a 24v incandescent test light that is aprox. 15ohms of resistance with a meter, so at 24V when load testing a wire it is about 1.6amps and 38.4 wats. Ill find a bigger bulb and retest again just to be sure.
Quite a few years ago on a 140H I had partial pressure loss on one clutch because there was a crack in the aluminium galleries of the valve body. There was an updated valve body available at that time. Generally the problem I find is a broken wire in the harness near the hitch for either the supply or return to a solenoid coil.
There is also a short harness (#1 below) actually mounted on the transmission, the one that feeds all the solenoids. The insulation on the wires of that harness tends to go hard over time and cracks, allowing oil into wires & connectors. Also the wires tend to fail where they are crimped to terminals in that harness.
I started into this and found this? Could this be a start to my problems?