Hello all new to the forum looking for any help I can get with this one. I have a cat 928G that while driving randomly kicks into neutral no indicators flashing at all. Been attempting to get this issue to repeat for me for about a week now since our normal operator is the only one who has been having this issue come up. Finally this morning I get in warm her up for about 5 minutes 36F outside release the parking brake, depress the brake pedal, and shift into forward 1, release the pedal and give it about 1/4 throttle. Machine starts to take off then finally it happened it really did just stop pulling just acted like it was in neutral with no warning lamps. I let off the throttle and gently press down again and no response other than rpm revving up as if it was in neutral. Here is some of the things that the last mechanic did to this apparently for the same reason. New trans oil New parking break lever New forward/reverse(1-4) lever Nothing showing for codes as far as flashing the code indicator light and nothing showing up on ET for active or stored codes, and nothing as for events. I have tested neutralizer switch, shift lever, and parking brake lever/switch all test good. Next in line I am guessing is testing the brake switches although doing the ET wiggle test seem to be functioning correctly. Now when I did get the issue to start happening the only way to get the machine moving again was to shift back to neutral and then back into gear while depressing the brake pedal. The shift into gear doesn't feel solid or crisp it is noticeable but nothing like some of the other CAT equipment we run. If brake switches test out good not sure where to turn next in trouble shooting this issue, not trying to throw parts at it.
Hello. Please write the serial number of the machine. If you have CAT ET, it will be easier for you to find the fault. When the problem occurs and the transmission stops, check the gear lever status, the neutralizer status and the transmission solenoids status in ET. Try also downloading the Status Report and sending it here to the forum. And does the fault occur in all gears? Forward and reverse?
What type & weight oil is in the transmission right now.? When the oil was changed did anyone change the filter and also remove the suction screen for inspection.?
Sorry got stuck on another job for a bit. Serial: 8CR01685 I will hook up and take it out driving see if it acts up again. It happens in all forward and reverse gears according to operator. The previous mechanic is no longer here and has yet to reply to communication with us. Only things I know about it are the CAT Trans and Drive train SAE 30 oil and filter looks to have been replaced this was completed 3 months ago 10 hours on the loader since then. Edit: Took it out for a drive and of course now she doesn't want to act up. All shifting seems completely normal now. I will try again Monday morning with ET hooked up and see what I can see if it acts up again. Apparently the the CAT techs were the ones who replaced the brake and shift levers assuming that was the problem before and had cleared any stored info at that time so I am working blind and nothing getting stored when it acted up this morning doesn't help at all.
So it's actually an IT28G rather than a 928G, not that it should make a lot of difference powertrain-wise - although it might do at some point. Who knows.? Is there any indication that the magnetic screen was ever removed.? See the attachment. If you can't determine one way or the other I would be tempted to drain enough oil out into a clean container to get the level below that screen then pull it and have a look. If you find anything interesting post photos. Also check the oil for a burnt smell and correct colour; should be clear & bright, not dark & cloudy. You have to start checking stuff off somewhere to get to the root of all this. Might as well start with the simple things.
Haha thanks for catching that, auto correct keeps adding the 9 before the 28g for some reason on the work laptop I didnt catch that. I will drain it monday and if the oil looks anything but clean I will replace and check the screen. No reason to believe what I cannot confirm from the old tech.
Make sure to take photos of anything interesting.
Will do, thanks for the advice sir. Other than the trans ecm on this loader is there another connector to read the rest of the machine? Only one I can find is this one under the right side of the cab behind the ladder after removing the plate to get to the trans ecm.
I'll send you the electrical schematic. Keep an eye on your message inbox.
Could the brake pedal be hanging up (slightly applied)? And with clutch disconnect activated, the switch on the pedal is closing, disconnecting the clutch? Can you shut off the clutch disconnect to test?
@Nige appreciate the help on that. Sorry ended up putting that project on the shelf for a while had a bunch of equipment that hadn't been serviced in years so I fixed all that up and now that I got some open time I am back to it. So I ended up draining the fluid which didnt have any metal that I could see or pick up from a magnet in it. Cleaned it all up put new fluid in. Tested wiring, cleaned up some grounds and all of the connectors to the ECM. Ended up finding the alternator was putting out the correct voltage but had an issue that while bouncing around the voltage was going out of spec enough for the ECM to read that and going into limp mode. Replaced the alternator and water pump since it sounded like the bearing was going out and I was already in there. Running great now, no more limp mode and now the crew just wont touch it because they have their brand new CAT loader with Heat and AC.
I hope you pulled the suction screen & magnetic filter assembly for inspection. I posted that procedure futrther up. If not you missed a trick.
Been a few years since we had our last 924G (similar machine)... I recall it had a button on the side consol or the dash you could switch between neutralising the transmission when pressing the brake pedal or not neutralising. Maybe that acts up, thinking you have your foot on the brake. Or the switch behind the brake pedal itself Edit i see you have found the issue...