I have this cat 140H motor grader that upon starting I can put my selector lever in anyone of the 1-8 drive gears forward or reverse. But after a couple minutes or sometimes a bit longer the Cat 140H will just like neutralize itself and i can not go nowhere till i shift back to neutral. After shifting to neutral it will move again but just for a short period then it neutralizes itself and am back at it again. The engine does not turn off just the tranny seems to jump into neutral while operating. And then I have to bring the selector lever back to neutral then to any gear so I can move it again. Has anyone had this problem?
Possibly one of the transmission shift coils on its way out. You need to get someone with ET to check it out. If you're absolutley desperate and/or can't find anyone with ET, I would chance a couple of hundred dollars and replace all eight shift coils. Not guaranteed to cure the problem of course, but greater than 50% chance, in my estimation.
Sounds like the shift solenoids, had a 12 H do a similar thing, used to loose a few gears intermittently then finally wouldn't have any in some speeds, hardest part is finding which one, there is a diagram in the parts book and also on the inside of the tranny guard there is a diagram to show which solenoid controls what speed ranges.
If an electrical schematic for the machine would be of any use to you send me a PM with the full machine Serial Number and your email address. Really without ET you're to a great extent dead in the water because when the transmission is acting up you need to be able to pull the Diagnostic Codes and see what exactly is the root cause of your problem.
Replaced 2 tranny solenoid coils ran for 1 hr hasn't shifted out of gear yet. Hope this problem is solved. Also I believe the manual says the tranny coils should be at 31 ohms plus or minus 3. Correct me if am wrong about that.
You don't mention what the S/N of your machine is, so I picked a CCA-prefix at random (there are 10 options). If the coil you are using in the transmission on on your machine is a 145-1144 the specification is 8.7+/-0.4 ohms. The offer of the electrical schematic still stands - see above.
Yep, definitely need a serial number for more accurate info on coil ohms. Nige's random pick of CCA happens to be a series II machine (plastic fuel tanks) and it has different solenoids for the speed and direction clutches. (Incidentally, the very sight of the prefix CCA was like someone walking over my grave. Brazilian made and guaranteed to rust out before your very eyes)
Thanks for those comforting words Cmark Actually, we had bit of drama with our CCA the other day. Machine stopped dead in its tracks without warning, motor and most electrics. Found fuse blown in key switch circuit, which we replaced, only to immediately blow again. Set up test light and began searching for a short. Four hours later, found the general location of the short, but after removing a saddle,insulated, and the outer layer of the harness, could not find any trace of damaged insulation. Couldn't get the short to reappear, so taped it up and put it back to work, been fine for two days since. Brazilian electrical gremlins, perhaps. Cheers, Greg
Must be the day for tranny coils. Our 12H 4XM did the similar thing before lunch today. Dropped the cover off and lo & behold the lower outer solenoid wires have chaffed on the cover.Ohm reading was 27. Looks like the wiring sheath is swollen from previous oil leaks from the test ports. The zippy ties are not helping either.
Ah, the famous Cat test ports. Guaranteed to leak within 12 months. I think I preferred it when you had to take a plug out and screw the quick coupler into the hole for the test and remove it afterwards.
The H series always seem to eventually give wiring problems where the two harnesses go through the hitch area. If we ever have the engine or tranny out of a machine approaching 10000hrs, I try to persuade the customer to replace the harnesses at the same time. Yes, they're moderately expensive at a couple of thousand dollars but then again, you can quickly eat through a couple of thousand in mechanic's time and downtime trying to repair a fault in this area.
Unfortunately a lot of machine owners don't seem to consider wiring harnesses as a "replaceable component" when doing component replacement or overhaul. I could never understand why you wouldn't replace the chassis wiring harness that connects to a component that cost tens of thousands of dollars to buy (or have rebuilt) at the same time as you replace the component itself.
And the old harnesses are a great source of random multicoloured wire and expensive deutsch plugs
Remember when we had EPTC-II transmission control on Cat OHTs..? Most of the issues I ever saw with that were down to wire breaks in harnesses, nothing else.
Yep. Cat harnesses as assemblies are probably the best made and most durable I've ever seen in off-highway machinery but the individual copper cables seem to fail with monotonous regularity. Or maybe by all other manufacturer's standards they're incredibly good but because I work on Cat stuff every day I have a distorted view of the world?
I have a 140H that has started acting up. You can shift thru gears 1-4 and all is good. When you shift into 5, it goes back into 1st, 6th goes into 2nd, 7th goes into 3rd & 8th goes into 4th. Any ideas?? Thanks
Have you done any sort diagnostics on it yet or are you looking for ideas of what to look at first..? It would appear at first sight that the low range clutch #7 that is used for 1st through 4th speeds is not dropping out and allowing the high range clutch #8 that is used for 5th trhough 8th speeds to engage. The reason for this could be mechanical or electrical. The machine Serial number would be a help.
Serial number is 2ZK06600
So, after more than 12 months of trouble free operation, our machine decides to pull the same stunt that I mentioned above. This time, while traveling flat bickie down the road and only allowing a few seconds of supplemental steering. Same fuse blown, which we replaced, only to blow again 2 minutes later. Removed saddle and taping involved with previous incident... No sign of damage to wiring... Replaced fuse yet again... Machine runs fine.(touch wood) Any thoughts?
Hi QLDR, our 12H 4XM has had the shift lever controller replaced for the same issue. Also replaced all the modulator coils-I think as a precaution .The machine has been fine again (touch wood) for 250hrs.
hi Greg, what fuse are you blowing Mark
Not sure if it was the bottom or second bottom fuse rhs steering fuse panel. The symptoms were similar to Alan except it would try to select reverse out of 5th forward.
As detailed to me by the operator it may well have been selecting 1st rather than reverse , as per Alan's machine. Didn't find any wiring issues apart for the oil impregnated coil wiring.
Mark, it is the fuse with the key symbol. I believe it is the main power relay circuit, wire no. 308. The problem area is just forward of conn. 27 where the harness is fastened to the frame before it disappears below the motor. Didn't think to check for codes after the event but it wasn't showing anything the week prior. Greg
Hi Greg, if you cant find the fault area. 1/you can replace the loom in question (the loom has been upgraded with different routing through the hitch area) 2/make an educated guess and bypass the suspect area 3/run another wire # 308-YL from the ignition switch to the main power relay , terminal #70 on the engine ECM and the Aux steering control if fitted. wire #308-YL also supply's power to the two voltage reducers and product link if installed Cat have braided replacement wire in different wire numbers and is an acceptable repair option if required I can supply part numbers for the wires and also supply the upgraded loom part number and special instruction if required Do you need an electrical schematic? Mark
Thanks for that info. Mark, We worked the grader over the weekend with no further drama, so Iam tempted to let sleeping dogs lie, at least until the next time I have an auto electrician near the machine again. I have a schematic but it wouldn't hurt to have those part numbers etc. Thanks again, Greg
My dear nige, I need the electrical diagram of a 12h motor grader prefix 4xm that has a fuel cut-off fault in 4 cylinders. I need to verify with the electrical diagram that I appreciate your prompt help
Is the 4XM machine Serial Number above or below 1396.? There are two groups of machines and a different schematic for each group.
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