Working on a CAT 446B, PN: 5BL03066 Tranny will intermittently stop working. Connecting ET to the machine, Transmission Selector Lever shows engaging F/N/R and gears 1-4. Tranny ECM will show F/N/R and gears 1-4 when its working (which is most of the time). When the tranny stops working......could be first thing, or it could have worked all day then stops working........gear selector shows working on ET..........but not working on transmission. Shut the machine off (key off), then start machine, goes back to working fine. So I just started working on this today............one thing of note..........it's a 12V system. I read on ET system voltage was 17V. Looked at voltage gauge on dash.........pegged right out. Multimeter confirmed it...........yup 17V. 5799H on machine Codes listed: ACTIVE CODES SHIFT LEVER- NO CODES TRANSMISSION 168-0 ELECTRICAL SYSTEM VOLTAGE HIGH 346-5 RIDE CONTROL RELAY CURRENT BELOW NORMAL 520-2 TRANSMISSION CONFIGURATION CODE : ERRATIC, INTERMITTENT, OR INCORRECT LOGGED CODES SHIFT LEVER-NO CODES TRANSMISSION CODE OCC FIRST LAST 168-0 ELECTRICAL SYSTEM VOLTAGE HIGH 127 5415 5799 191-2 Transmission Output Speed Sensor:Erratic, Intermittent, or incorrect 127 5028 5680 668-9 Transmission Shift Lever:Abnormal Update Rate 1 5782 5799 346-5 Ride Control Relay: Current Below Normal 1 5744 5799 520-2 Transmission Configuration Code: Erratic, Intermittent, or incorrect 1 5714 5799 First thing to be corrected is the alternator so it's not cooking the system w/ 17V. I've seen the shift lever being bad on 416's before. But I'm still seeing the Shift Lever doing what it is supposed to do in ET. CAT wants $1430 for this part. I figured I'd go through connections and connectors after I get the alternator fixed. Looking for some suggestions from someone who might have run into this before. I'm really leaning towards the shift lever..........logged code. Anyone know what the transmission configuration code means?? Thank you in advance for the help.
PROBLEM SOLVED So 5799H on ECM clocks, 6846H on mechanical clock on dash. Pulled alternator, replaced regulator, gave alternator quick check then put it back in. The day I pulled the alternator, system voltage was 18.5V. Backhoe has been running for a few days now, no hiccups, tranny working fine and shifting without a problem. Problem: system over voltage Check system voltage.......shouldn't be over 14.5V DC. With digital multimeter, switch it to AC.......this will check the diodes. You should show 0V AC on the multimeter. If your reading AC voltage, then the diodes are bad or going bad. Maybe this will help somebody.........
Update 2/19/24 Definitely an over voltage issue. Machine has been running fine and hasn't missed a beat with the transmission dropping out. Alternator putting out too much voltage was the issue. Sometimes its the simple things that are the problem.