CX31 and CX31 HT On-Highway Transmissions Reference Material Caterpillar

Reference Material
1.1. CX31 On-Highway Transmission References
2.1. Caterpillar Reference Material
3.1. Additional Reference Material
4.1. Description of Applications
5.1. CX31 Ratings
6.2. Transmission Applications
7.2. Acronyms

CX31 On-Highway Transmission References


The Operations and Maintenance Manual and Installation Guides are stored and printed from an electronic file. These files are revised periodically. To ensure that your hard copy of the document is the current version, consult your AVSpare Representative. All paper copies are uncontrolled.

Special Instruction, REHS2790, "Mechanical Application and Installation Guide for the CX31 On-Highway Transmission"

Special Instruction, REHS2884, "Electrical Application and Installation Guide for the CX28, CX31, and CX35 On-Highway Transmissions"

Parts Manual, SEBP5959, "CX31 On-Highway Transmission"

Disassembly and Assembly, UENR0125, "CX31 On-Highway Transmission"

Systems Operation, Troubleshooting, Testing and Adjusting, KENR8274, "CX31 and CX31 HT On-Highway Transmission Power Train Electronic Control System"

Specifications, System Operation, Testing and Adjusting, UENR1833, "CX31 and CX31 HT On-Highway Transmission"

Schematic, UENR1796, "Electrical System", "CX31 On-Highway Transmission"

AVSpare Reference Material

Special Publication, PECP9067, "One Safe Source"

Special Publication, SEBU6250, "AVSpare Machine Fluids Recommendations"

Special Publication, SEBU5898, "Cold Weather Recommendations for All AVSpare Machines"

Special Instruction, SEHS9031, "Storage Procedure for AVSpare Products"

Special Publication, NENG2500, "AVSpare Tools and Shop Products Guide"

Service Manual, SENR3130, "Torque Specification Module"

Special Publication, PEHP7076, "Understanding S·O·S Services Tests"

Special Publication, PEHP6001, "How to Take a Good Oil Sample"

Additional Reference Material

SAE J754, "Nomenclature" Nomenclature can normally be found in the SAE handbook.

SAE J183, "Classification" Classification can normally be found in the SAE handbook.

Description of Applications

On-Highway vehicles operate elusively on roads that are improved or normally paved. Typical vocations are: pickup and delivery, beverage delivery, public service dump trucks, utility trucks, tank trucks and tour coaches.


Severe Duty

On/Off Highway: Vehicles that operate both on and off highway. Typical vocations: dump, transit mixers, all wheel drive, utility, snow removal, yard spotter, concrete pumper and other vocations with severe PTO applications.

Refuse: Refuse and garbage disposal applications.

HET: Heavy equipment transport.


Emergency Vehicles: Fire trucks that are typically designed to NFPA guidelines.

CX31 Ratings

Transmission Applications

Table 1
Item Description  CX31 
CT11 CT13 CT15 
Maximum Gross Input Power  hp (kW)  390(291)  475 (354)  550 (410) 
Maximum Gross Input Torque  lb-ft (N.m)  1450 (1965)  1700 (2305)  1850 (2508) 
Maximum Turbine Torque (forward)  lb-ft (N.m)  2600 (3525)  2600 (3525)  2600 (3525) 
Maximum Turbine Torque (reverse)  lb-ft (N.m)  2200 (2983) 
Rated Input Speed  rpm  2100 
Minimum Input Speed  rpm  600 
Maximum Input Speed  rpm  2500 
Dry Weight Without Retarder(1)  lb (kg)  906 (411) 
Dry Weight With Retarder(1)  lb (kg)  1088 (494) 
Forward Reverse Gears  6F/1R 
Planetary Gear Ratios 
1F  4.40 
2F  2.33 
3F  1.53 
4F  1.00 
5F  0.72 
6F  0.61 
1R  3.97 
Overall  7.21 
Torque Converters 
TC42531  STR 2.7 
TC42833  STR 1.9 
(1) This transmission does not include the following components: crankshaft adapter, flex plates, starter ring gear, bolts, output yoke and ECU. ( 29 kg (64 lb))


Table 2
Acronyms  Description 
A and I  Application and Installation 
A/C  Air Conditioner 
ABS  Anti-lock Braking System 
CID  Component Identifier Diagnostic (code that informs the service personnel of specific component or system failure) 
CTS  Controlled Throttle Shifting (significantly reduces power train stress and clutch wear by controlling engine speed, torque converter lockup, and transmission clutch engagement) 
ECM  Engine Control Module (controls all aspects of engine emission compliance, performance, operator/chassis interaction, and diagnostics) 
ECU  Electronic Control Unit (electronic device used to control transmission functions) 
ECPC  Electronic Clutch Pressure Control (design senses input from the transmission and the operator controls to modulate each individual clutch through a proportional electro-hydraulic valve) 
FWH  Flywheel Wheel Housing 
HET  Heavy Equipment Transport 
LUC  Lockup Clutch 
OEM  Original Equipment Manufacturer 
PT  Power Train (transmission and auxiliary components) 
PTO  Power Take-Off. (PTO referred to in this manual is engine rpm control initiated through a dedicated PTO ON/OFF switch circuit connected to the ECM Input No. 1) 
SAE  Society of Automotive Engineers (standards) 
STR  Stall Torque Ratio (torque converter stall torque ratio) 
OMM  Operation and Maintenance Manual 
kPa  x 0.145 = pressure (PSI) 
bar  x 14.5 = pressure (PSI) 
kW  x 1.34 = horsepower 
L/min  x 0.26 = gallons/min 
N·m  x 0.74 = ft × lb 
S·O·S  Scheduled Oil Sampling 

Information System:

C15 and C18 Engines for Caterpillar Built Machines ECM - Replace
CX31 and CX31 HT On-Highway Transmissions Capacities (Refill)
349F and 352F Excavators Machine System Specifications Track Carrier Roller
188-3922 Broken Exhaust Bolt and Stud Removal Group for 3114, 3116, 3126, 3126B, 3176, 3176B, C-10, and C12 Engines{0374, 0599, 0701, 0702, 0703}
CX31 and CX31 HT On-Highway Transmissions Transmission Operation
CX31 and CX31 HT On-Highway Transmissions Transmission Control
Using the 9U-5792, 4C-5052, 4C-5054, 4C-3670, and 4C-3680 Hydraulic Hose Machines{0374, 0599, 0684, 0738, 5057}
C15 and C18 Engines for Caterpillar Built Machines General Information
Three60 Precision Control System System Overview
CX31-P600 Petroleum Transmission Power Train Hydraulic System
2013/10/02 Improved Gear Train Components are Now Used on TH48-E80 Petroleum Transmissions {3064, 3160}
Procedures for Using the 212-1503 Portable Parts Washer{0374, 0599, 0680, 0699, 0700}
2013/11/04 New Boost Pressure Sensor Location Is Used for Certain 3512 Petroleum Engines {1408, 1439, 1917}
C13 and C15 Generator Sets Generator Start-up Checklist
C15 and C18 Engines for Caterpillar Built Machines Programmable Parameters
G3600 A4 Engines Coolant (NGEC) - Change
G3600 A4 Engines Coolant Level - Check
Quick Start Wiring Guide for Dynamic Gas Blending Well Service Engines{1000, 1408, 1900, 1901, 7610, 7620}
G3600 A4 Engines Cylinder Pressure - Test/Record
G3600 A4 Engines Engine Air Cleaner Element (Single Element) - Inspect/Clean/Replace
G3600 A4 Engines Engine Valve Lash - Check
C15 and C18 Engines for Caterpillar Built Machines Electrical Connectors
C15 and C18 Engines for Caterpillar Built Machines Alternator Problem
374F and 390F Excavators and 390F MHPU Mobile Hydraulic Power Unit Event Codes