Good Morning, I'm Bailand and new to this forum. My CAT D3 will push great for a few minutes then shifts down to low and stays there. If I shut it off then back on it works fine for a while (it varies in time) then back to creep mode. The control button has no effect when it slows down and the speed indicator stays pegged all the time. Any direction would be much appreciated
Whats the battery voltage and when was the last time it was calibrated. Does it have any active codes
X2 - Need this info. Oh yeah - Welcome to the Forums Bailand! Glad to have you.
@Bailand - post a machine Serial Number please. Also do you know how to access Diagnostic Codes on the machine.?
I have the machine apart at the moment flushing out the fuel tank and replacing the lift pump. I should have it back up today and will check the voltage. the S/N is JMH01577. The temp is always in the operating range. It does the downshift thing shortly after starting work so it hasn't had time to really heat up. I do not know how to retrieve diagnostic codes.
You do now. See the attachment. I suggest that you access the Codes first and see if anything comes up before proceeding further.
Just checked battery voltage at about mid RPM, 13.65V
That's a start. These machines like a consistent 14.4 volts or weird things happen on the tractor. I am no mechanic by any stretch of the means just learned this the hard way after owning a '04 D5G for 22 years.
Not really enough. Are the fan belts correctly tensioned.?
Fan belts appear to be properly tensioned. I just printed out the code retrieval procedure to give that a whirl. Just like to say I appreciate your input.
That kind of voltage at mid RPM is indicative of alternator problem, or some bad connections on the way from the alternator positive output terminal to the Battery Positive post. Was just looking at RENR7313-03 Troubleshooting guide and near the end of the entire lengthy Codes troubleshooting there was a list of all the possible Alternators your machine can come with including some that ran on 24 volts. The fact that you posted 13.65 Volts leads me to believe that yours is the 12 volt system. I do not have the schematic for your machine, but regardless the alternator should not lose 0.5 volts from the Alternator Positve output post to the center of your Battery Positive Terminal with the engine revved up and lights and fans on to force the alternator to output and flow current. Try that test with your Meter on DC and the Red Positve Test Lead on the Alternator Output Post, and with your Black Negative Test Lead on the Battery Positive Post to measure loss of potential. If you get a reading of 0.5 volts, you will know that your cables and connections are weak somewhere on the travel to the battery Positive post. If the reading is low then your Alternator could be suspect, other that if there is a flat braided ground strap coming off your alternator to the engine block like I seen on another model newer Cat 2 weeks ago. If there is too much resistance in that ground strap your alternator may not work correctly. Easy test is to engine running at Mid RPM with lights on and fan on to stab the case of the Alternator with your Red test lead and the center of the Battery Negative Terminal with the Black test lead. If you have a reading over 0.5 volts you have some connections on the ground side needing cleanup or repaclement. I just went through this last week on a skid steer track machine that the braided ground strap was badly corroded and could not be seen until removed. The machine only had 1100 hours, and it was a really beefy strap but was still junk. Not saying this is your problem, but I could test all these things in only a few minutes, and they would be ruled out with certainty. If your alternator has other wires controlling the charge rate then they would have to be tested. Post a picture of the back of your Alternator if you have time. Simon C
It is a nominal 12v system on that machine. Don't you have a copy of RENR7853 electrical schematic.?
No I don't have the schematic for that G series dozer although I do have others. When I have one I like to take a few simple notes or take a picture with my phone of the area I am looking at as I can see the wire numbers and size of wires. I find the schematic can lead you to a plug, or show exactly how many ground connections there is which can help greatly in speeding up the diagnosis for people. Simon C
I read the fault code (at least the first one) and it displayed 256 which is Position sensor (steering). I'm going thru the troubleshooting section CID 1700 to see if I can pinpoint the culprit. If I understand the diagnostic procedure to see if there's any more codes you connect pins 1 + 2 on the harness connector?
Ha Bailand, I have the same problem you have. I also have schematics. Can send if you want
Thank you for that Ray1954, I might need the schematics but need find out what system is at fault first. Here is something that I thought was a totally separate problem but the more I check into it the symptoms seem related. I am also having a fuel problem that started about two weeks ago when we were clearing a river bank slope of about 50 degrees and it seemed to stir up all the junk in my tank. Emptied the tank, flushed it with fresh fuel, changed the filter and cleaned the screen on the lift pump and it ran great for about 20 min. It looks like I might have algae in the tank along with a bunch of rust, dirt and other junk. even though I flushed it, it seems to have more in the tank. Is it possible that the engine sensors are affecting the drive speeds?