140H Motor Grader, lost all reverse gears and forward 3,4,8.

Update: The wiring was thoroughly followed and fixed but the issue remains same no forward gears 3,4,8. And reverse (3,6) others are perfect. Adapted to the ET tool and only 1 active code remains which is: “177-4 Transmission Oil Temperature Sensor: Voltage below normal”

Update 2: the error was fixed and now no active codes are visible. The issue the machine came with initially persists no forward gears (3,4,8) and reverse (3,6) we are doubting the dowel can be one the reasons of the missing gears. We have not run pressure tests yet once we push out the dowel into it’s original position and then shall observe difference.

I think we had a communication problem up to now. I read that you were missing ALL Reverse gears, not just 3R & 6R. That being the case the common factor is Clutch #5. Clutch #5 should also be engaged when the transmission is in neutral. See the chart below. Hook up a 500psi gauge on test point "E" on the control valve. Start the engine with the transmission control in neutral. I'm guessing that you will have no pressure, or at least very little, at that test point.

Before yes all reverse were missing, but now it’s the others are engaging fine except the gears 3 and 6 which was the issue the machine had when it came in initially and the transmission overhaul was done.

Nik3002 said: Before yes all reverse were missing, but now it’s the others are engaging fine except the gears 3 and 6 which was the issue the machine had when it came in initially and the transmission overhaul was done. Click to expand... Thanks for confirming that. In that case you are chasing a problem in #5 clutch. See above. it is convenient that clutch is also engaged in neutral. If you get no pressure on that clutch then as a first step check if the solenoid valve for it is receiving power.

Everything has gone quiet. Any updates.?

We have performed the necessary tests for initial pressure and concluded that the initial pressure was really low. Added shims and replaced the springs the initial pressure is perfect, yet still no gears on clutch 5. No errors with solenoids detected. We are doubting a mechanical failure of the items 1,3,8,10. Waiting for tomorrow so that can dismantle the transmission and inspect thoroughly inside. Today we will complete the pressure adjusting for the other 140H once the control valve is set.

Nik3002 said: We have performed the necessary tests for initial pressure and concluded that the initial pressure was really low. Added shims and replaced the springs the initial pressure is perfect, yet still no gears on clutch 5. No errors with solenoids detected. We are doubting a mechanical failure of the items 1,3,8,10. Waiting for tomorrow so that can dismantle the transmission and inspect thoroughly inside. Today we will complete the pressure adjusting for the other 140H once the control valve is set. Click to expand...

Nik3002 said: We have performed the necessary tests for initial pressure and concluded that the initial pressure was really low. Click to expand... What initial pressure were you measuring on clutch #5.? I know you said you had done work on the control valve. Did you check for spec and/or replace any of the springs.? That leads to a follow-up question of how many total hours are on this particular machine.? When the transmission was first disassembled were the 3 x rotating seals #19 and the O-Rings #22 also replaced..? After rebuilding any grader transmission clutch shaft you can check for piston seal leaks by applying shop air pressure to the end of the shaft (before installing the stub shaft) and with a lump of rag over the hole in the end of the shaft. It's a rough & ready test but works pretty well.

not really sure as I was absent whilst the pressure test was carried out, but I was able to get the results! Regarding the seal replacement, yes we did replace the rotating seals and o-rings. We have a transmission repair kit in stock for such emergencies and regardless of the condition all seals and o-rings are replaced. The pressure leak was also test was performed and it showed no signs of pressure leak. Waiting to dismantle the transmission again to inspect the gears for damaged splines. The picture attached below is for the pressure test that was performed.

I don’t see a photo.

I guess it did not upload, let me attach it again.

Judging by those numbers there were other clutches far worse than #5. In fact pretty much all eight of them were out of spec on initial pressure. When it comes to setting initial pressures I am a big believer in setting the adjuster for each valve station in the centre then getting as close as possible to spec by adding or subtracting shims. After that a small tweak of the adjuster normally gets the pressures bang on. Are you aware that there is an updated parts list, and different initial/final pressure specifications, for #7 clutch.? So depending upon whether that section of the control valve was updated or not you might be using the wrong spec.

I mean we had a technician from Mantrac (Caterpillar) do this test and yes the pressure is not to spec and was later adjusted (by the technician) but was unable to get the new pressure results after adjusting because the new results were misplaced. If you can provide the updated parts list and pressure spec, i would appreciate it very much.

Nik3002 said: I mean we had a technician from Mantrac (Caterpillar) do this test Click to expand... That being the case he should already have known.......... In order to determine what the correct IP specification for #7 clutch you will first need to look at the spring(s) in that particular station in the control valve. If it has 2 springs it has already been updated. If it has 1 spring it has not. In the case of the latter see the attachment. You never stated how many hours are on the machine. As I mentioned earlier if it was mine and had significant hours on it I would measure the free length of all the springs and compare it to the relevant specification. If anything around half of the springs were on the edge or out of specification then I would then replace all of them. If you think about it a number of tired springs in the control valve could be the reason why the Initial Pressures are so low across the board.

Yes sir, we were suggested the same thing, to replace springs. I will take a look at the documents you provided tomorrow and get back to you. Thank you once again.

I have got one more question. Do you get these updates on SIS, because we are a small firm and we do not have access to the latest SIS thus, we have to rely on a cracked version for parts identification and troubleshooting. Sometimes purchasing locally has a long process to get part numbers plus the waiting time for parts is long as well and we would rather import parts from brands like CTP or suppliers from UAE than to wait for weeks to get replacement parts. Is there a way to subscribe to SIS to get the latest updates? The latest cracked software we use is from the year 2017 if im not wrong, but I will check once in office.