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Cat 143h transmission

Cat 143h transmission

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GEORGIOS198217

Well-Known Member
Joined
Sep 18, 2020
Messages
83
Location
Greece
My serial number is 1al00815. But caterpillar told me that the control valve is changed and that is from a newer model but is ok it can work . The coil is all the same?
 

Nige

Senior Member
Joined
Jun 22, 2011
Messages
28,985
Location
G..G..G..Granville.........!! Fetch your cloth.
I still have problem. I repair the trans control but still I don’t get all gears.now it can’t engage 1 f and 5 f and 1 and 4r. What can happen? I put all coil new. I am afraid that the wires are confused. Can someone give me the plan of the wires with colors to check?
if you are missing those particular gears the problem (electrical or mechanical I have no idea) is in #6 clutch.

I would guess that you have everything connected correctly because the transmission is behaving normally other than the 4 speeds that are not working - but all those 4 speeds are relsated to only 1 clutch.

Have you ever removed the suction screens to look for clutch debris.?

upload_2020-11-21_12-12-4.png
 

GEORGIOS198217

Well-Known Member
Joined
Sep 18, 2020
Messages
83
Location
Greece
if you are missing those particular gears the problem (electrical or mechanical I have no idea) is in #6 clutch.

I would guess that you have everything connected correctly because the transmission is behaving normally other than the 4 speeds that are not working - but all those 4 speeds are relsated to only 1 clutch.

Have you ever removed the suction screens to look for clutch debris.?

View attachment 228295
Yes it was clean
 

Mark250

Senior Member
Joined
Aug 30, 2015
Messages
1,243
Location
victoria,Australia
Occupation
heavy equipment technician
hi George
it is a bit confusing because solenoid numbers don't line up with clutch numbers I will try and explain
sol A = clutch 3
sol B = clutch 1
sol C = clutch 2
sol D = clutch 8
sol E = clutch 4
sol F = clutch 6
sol G = clutch 5
sol H = clutch 7

the wire colours in order for the first row will be from the top
green and white
yellow and white
blue and white
orange and white
for the second row the wire colours will be from the top
purple and white
white and white
brown and white
grey and white
As you can see you are correct and the tails are in order
 

GEORGIOS198217

Well-Known Member
Joined
Sep 18, 2020
Messages
83
Location
Greece
hi George
it is a bit confusing because solenoid numbers don't line up with clutch numbers I will try and explain
sol A = clutch 3
sol B = clutch 1
sol C = clutch 2
sol D = clutch 8
sol E = clutch 4
sol F = clutch 6
sol G = clutch 5
sol H = clutch 7

the wire colours in order for the first row will be from the top
green and white
yellow and white
blue and white
orange and white
for the second row the wire colours will be from the top
purple and white
white and white
brown and white
grey and white
As you can see you are correct and the tails are in order
Thanks mark i will try right now
 

Mark250

Senior Member
Joined
Aug 30, 2015
Messages
1,243
Location
victoria,Australia
Occupation
heavy equipment technician
number 4 clutch is common to the lost gears
you can move solenoids around to see if the problem moves as a first move. but normally if the wire or solenoid is open you will not get gears past that point
if you have testing equipment check the pressure at the clutch test point

when you removed the control valve did you fit the correct CAT o rings and torque the retaining bolts to 30nm or 22 lb these aluminium valve bodies can do strange things if not treated correctly
 

GEORGIOS198217

Well-Known Member
Joined
Sep 18, 2020
Messages
83
Location
Greece
number 4 clutch is common to the lost gears
you can move solenoids around to see if the problem moves as a first move. but normally if the wire or solenoid is open you will not get gears past that point
if you have testing equipment check the pressure at the clutch test point

when you removed the control valve did you fit the correct CAT o rings and torque the retaining bolts to 30nm or 22 lb these aluminium valve bodies can do strange things if not treated correctly
I do that but nothing. The valve was rebuilt by caterpillar.I think that i have no volt at E coil
 

Mark250

Senior Member
Joined
Aug 30, 2015
Messages
1,243
Location
victoria,Australia
Occupation
heavy equipment technician
have you checked for continuity of the wires between the ECM and the solenoid (I thought you said you did in an earlier post)
As I said in an earlier post you need to have good wire continuity and a good coil before the ECM will deliver 24 V to the coil
if there is an open circuit coil all you will measure is usually about 5v or zero if the wire is broken
So leave coil connected and back probe the coil connector to check for voltage if no voltage at coil connect a good coil directly to the ECM under the cab and check there
 
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