Caterpillar 140H transmission problem

[Chaippah]

May u please help me with a workshop repair manual for 140H
Motor Grader

 

[Nige]

The only apparent source for shop repair manuals is an internet site such as eBay or Amazon.

 

[Z2898]

Just a few things to note to understand this H series transmission.

Its a countershaft not a planetary

KBeen is correct- 3 clutches need to be applied to get movement from machine.
In any gear selection you should have 3 transmission shift coils energized. (check them with a ferrous material like a screwdriver)
If only 2 coils are energized it wont move.

If you are getting a "High" current code this is usually an indication that there is an internally shorted coil. Swap it with one that you know is good and try it.

 

[PascalDao]

Hello Guys, I am currently working to fix a Caterpillar 140 H motor grader that won't select any gear. I changed the control valve and ECM and it started selecting gears. However, the next day I changed the transmission oil because it was low, but when I started the machine it was acting oddly. It sometimes selects a gear, and sometimes does not. Or it will get into gear, and suddenly lose the gear. I noticed directional solenoids 1, 2 and 3 are the ones whose clutch stations don't have pressure when gears don't get selected. I changed solenoid 3 and all reverse gears worked properly for the first 5 minutes and then went back to not selecting gears. Has anyone ever seen anything like this, I am desperate for help.

 

[Mark250]

Hi a serial number will be needed there are too many differences
Also brief history and why you changed out the Valve and ECM
Mark

 

[guiré mahamat ismail]

Having a problem with a 140H grader. I am sure its a simple fault but I cannot access SIS right now to give me an idea of pressures etc. Its a basic 5HM machine with mechanical pump on 3306. I have run ET and it shows only VHP solenoid as being high current. The machine will select all gears when the wheels are raised in the air (suggesting signal to solenoids is ok) but if you put it back on the ground it will only drive in gears 5678 forward and 456 reverse. In these gears it has plenty of drive and in the non working gears the machine will move very slightly. The oil looks clean. I am not sure how the transmission is configured internally but I am almost certain that somebody will be able to tell by the gears that are working. The valve block has been dismantled before from what I can tell. Any help would be much appreciated as here in Sierra leone I am pretty much alone and being a VOLVO trained fitter is not helping right now. Thanks in advance.
Pete

Hello
I also have the same problem with the 140h. Is it possible that the ECM is partially out of service when a few speeds pass and others not?

 

[guiré mahamat ismail]

Hello
I also have the same problem with the 140h. Is it possible that the ECM is partially out of service when a few speeds pass and others not?

 

[Nige]

Two questions: -
1. Which speeds are not working..?
2. Have you removed the transmission suction screen to check for burned clutch material..?

 

[guiré mahamat ismail]

Two questions: -
1. Which speeds are not working..?
2. Have you removed the transmission suction screen to check for burned clutch material..?

Hello Mr Nige
- Forward speed 5 to 8 only no 1 to 4
- Reverse speed 4 to 6 only no 1 to 3
- the transmission suction screen checked: nothing special

 

[Nige]

Is this something that appeared suddenly..?
If I recall correctly the maxmum gear in both forward and reverse in the transmission can be programmed to limit the ground speed. This machine sounds to me as though it has been programmed to not shift above 6th speed forward and 3rd speed reverse. I used to do the same thing to stop grader operators speeding on haul roads.

 

[guiré mahamat ismail]

Is this something that appeared suddenly..?
If I recall correctly the maxmum gear in both forward and reverse in the transmission can be programmed to limit the ground speed. This machine sounds to me as though it has been programmed to not shift above 6th speed forward and 3rd speed reverse. I used to do the same thing to stop grader operators speeding on haul roads.

Of course the failure occurred suddenly. Before all the 8 forward speeds and the 6 rearward worked without problems. we already changed the gear lever

 

[Nige]

My apologies, I misread your post. I thought you were only getting the lower four forward gears (1-4) and not the higher forward gears (5-8) but in actual fact the situation is the opposite - you have 5-8 forward but not 1-4.

The common factor in your "missing" gears both forward and reverse is clutch #7. If you have no burned clutch material in the screen then the first thing I would try is swapping the control solenoids between #7 and #8 clutches. If the #7 solenoid is bad then after the swap you should have speeds 1-4 forward and 1-3 reverse but not 5-8 forward and 4-6 reverse. On the side of the transmission control valve is a plate (#13 on the illustration) that shows which solenoid is which.

 

[andu]

hi, I have aproblem with cca motor grader with transmission, the problem is ,there is no speed for gear 2,3 and 6 forwards only and also when I try to measure the preasure it is 0 for the commen clutch no.2 but the paring two cluches have apressue. also Itry to swap the no.2 harness with no.1, the problem goes to for the gear no. 1 commen forwards(no.1,4,5,7and 8) and when gear no.2 is selected but the pressure for port no.2 is steel 0 but gear have speed.so please help me what can I do.

 

[Nige]

Have you checked the condition of the transmission pump suction screen to look for burnt clutch material.?
Does the oil smell burned.? Is it dark in colour.?

 

[andu]

Yes I chacked and it was looked burnt and smalled burned then Ichanged the clutch for the burned ones but the problem is the same.

 

[Nige]

then Ichanged the clutch for the burned ones but the problem is the same.

Do you mean that you removed the transmission and repaired the damaged clutch.?

 

[andu]

Do you mean that you removed the transmission and repaired the damaged clutch.?

Yes

 

[Nige]

Ok, I have read your first post again to try to understand it better.

Right now you have no drive in speeds 2, 3, & 6 Forward. Is that correct.?

Please can you describe in detail exactly what you did to change the symptoms from no drive in 2/3/6 Forward to no drive in 1/4/5/7/8 Forward.?

 

[andu]

Ok, I have read your first post again to try to understand it better.

Right now you have no drive in speeds 2, 3, & 6 Forward. Is that correct.?

Please can you describe in detail exactly what you did to change the symptoms from no drive in 2/3/6 Forward to no drive in 1/4/5/7/8 Forward.?

ok sir, I made swaped the harness for proportional solenoids from solenid no.e to solenoid no.1, then the I try to select the no.2 gear on the gear selector lever, now the speed is there but when I try to measure the preasure for no.2 on test port no.2 it is zero, but Igate preasur on test port 1.

 

[Nige]

Ok. Try these two steps for diagnostics.

STEP 1: Keep the wiring original and physically interchange the solenoids between the two valves. Does the problem move from 2/3/6 to 1/4/5/7/8 by interchanging them.?

If the problem moves then the solenoid is bad. Replace the solenoid.

If it does not move, go to Step 2.

STEP 2: Keep the wiring original but this time interchange the two complete solenoid valves.

By that I do mean interchange the complete valve - body + solenoid. First remove each solenoid that will give you access to the hexagon on the valve body. Interchange the two valve bodies and make sure to install the solenoid that originally corresponded with each of them.