Transmission (EPTC-II) EUI Retrofit{1900, 3150} Caterpillar

Introduction

This Special Instruction provides the necessary information to install the transmission portion of the Electronic Unit Injection (EUI) Conversion on a Mechanical Unit Injection (MUI) 789 Truck. THIS INSTRUCTION SHOULD BE KEPT WITH THE TRUCK. The parts and assembly procedure will not be available in any other publication.

The major areas of change are the transmission control box, transmission adapters and valves, transmission speed sensor, body down sensor and center console harness.

NOTE: There are two basic style of large connectors which may have been used on this machine. These are the CE and VE connector. The CE connector is the latest connector manufactured by Deutsch®. The VE connector (no longer used) was manufactured by Cannon®. Some machines may have both style connectors. The tooling used for removing and installing pins and sockets must be designed for that particular connector.

Reference: SEHS9485 Converting ICM Transmission And Torque Converter Lock-up Controls To Spool-Type Solenoid Valve Group, SMHS8617 Installation Procedure For Transmission Speed Sensor, SEHS9065 Use of CE Connector Tools, SEHS8038 Use of 6V4810 VE Connector Tool Group, 789 Parts Manual.

Parts Needed

Transmission Control Box

1. Remove the rear cab cover.

2. Remove the cover from the center console.

3. Remove the transmission control from the console (two bolts on each side).

4. Disconnect the existing transmission control harness from the control group.

5. Lower the back of the buddy seat and remove the panel on the rear of the cab. This will make it easier to drill the holes for the switch bracket.

6. Drill two 12.2 mm (.5 in) holes in the plate as shown in the illustration and photo. The plate can be used as a template.

7. Mount service set and service clear 9D3721 Switches (21) to 8X9638 Plate (20) with the hardware furnished with the switches.

8. Fasten the plate and switches to the plate with 5M3062 Bolts (22), 8T4896 Washers (23) and 6V8801 Nuts (24). Leave the bolts loose because the bracket may have to be removed later to install the control unit.

1047116 Harness Assembly. A. Transmission Fuse. B. Ground Boss. C. Engine and Transmission Data Link. D. Transmission Main Connector. E. Transmission Control Connector. F. Service Set and Clear Switches. G. CE connections at cab wall (not shown).

9. Install 1047116 Harness Assembly (19) by feeding the ground boss, CE wall pin connections and the transmission fuse connector through the cone shape grommet at the rear of the cab wall.

10. Remove the endbell from the existing harness connector and slide it down the harness. Insert the control wires through the endbell (four 202-BK and E750-PU).

NOTE: When installing any wires into the connector, they must first go through the endbell.

NOTE: Always use the correct tool when removing or installing sockets in a connector. If the proper tool is not used the connector will be damaged.

11. Remove sockets 17, 18, 19 and 37 from the existing transmission harness connector. Cut the ends from the wires, tape each wire, and tie back the wires to isolate them from shorting against themselves and other wires.

12. Insert one of the 202-BK socket connections (from the 1047116 Retro Harness) into each of the following locations (18, 19, 36 and 37). The remaining 202-BK wire should taped and tied back as being unused in this update. This completes the coding of the transmission control box.

13. Insert E750-PU wire from the 1047116 Harness Assembly into location 27.

14. Fasten 3E6014 EPTC-II Film (14) to the face of the control.

15. Fasten two 5T9364 Plate Assemblies (15) to the bottom of the transmission control with four 0S0509 Bolts (17).

16. Install the transmission control in the console with four 6V8969 Screws (16).

17. Connect the main connector to the controller. Connect the new additional breakout from the control box (10 pin sure seal) to 1047116 Harness and fasten with existing clip assembly.

18. Connect the 2 pin sure seal (Data Link) to the EUI Retro Harness which was plugged during the retro harness installation (reference 1047114 Harness). Use the existing 3T3048 Clip Assembly.

20. 8X9638 Plate. 21. Two 9D3721 Switches. 22. Two 5M3062 Bolts. 23. Two 8T4896 Washers. 24. Two 6V8801 Nuts. X. D997-YL Wire. Y. 202-BK Wire. Z. D996-PU Wire.

19. Connect the D997-YL, D996-PU and 202-BK wires to the switches as shown.

20. Tighten the switch bracket and replace all panels.

21. Fasten the ground terminal of the retro harness to the ground boss on the rear cab wall.

22. Fasten the harness to the transmission fuse which is located on the circuit panel. The fuse holder has only one connection blade so the EPTC-II retro harness provides a short connector so that the existing transmission fuse wire (126-PK) may plug into the Retro Harness to form a splice connection.

23. Remove 126-PK wire of the fuse panel harness from the transmission fuse. Then 126B (part of the retro harness) should be connected to the fuse with 126C being a new connection point for fuse panel 126-PK spade.

NOTE: When installing any wires into the connector, they must first go through the endbell.

NOTE: Always use the correct tool when removing or installing sockets in a connector. If the proper tool is not used the connector will be damaged.

24. Insert three wires into the existing transmission harness connector on the cab wall.

E750-PU wire goes into pin location 11.

126-PK wire goes into pin location 18.

202-BK wire goes into pin location 16.

25. Assemble the connector.

26. Replace the rear cab cover if all the modifications are completed in this area.

Body Down Sensor

1. Locate 1029162 Plate (26) to the inside left frame rail as shown in the illustrations above.

2. Make a 5 mm (.2 in) fillet weld, both sides, at location (A).

3. 1051133 Harness Assembly (28) supplies power to the body down sensor. This harness has three connectors that must be inserted into the CE or VE connector of the existing chassis transmission harness at its location on the outside of the cab wall.

4. These socket connections will match those made on the cab transmission harness.

E750-PU wire goes into pin location 11.

126-PK wire goes into pin location 18.

202-BK wire goes into pin location 16.

Assemble the connector.

5. The 1051133 Harness Assembly should be routed to follow the existing transmission harness from outside of the cab wall, down the frame support, along the inside of the left frame, over the cross tube and then separate from the existing harness.

6. It will continue to run to the rear of the machine along the left inside frame back to the newly welded plate. Use 7K1181 Straps (39) and include harness in existing clips to secure.

25. 8T4896 Washer. 28. 1051133 Harness. 31. 3V6909 Block. 32. 4D7794 Clip. 33. 4L6454 Bolt. 34. 4M0061 Bolt. 35. 4V4760 Cover. 36. 5S7379 Bolt. 38. 6V8189 Nut. 40. Two 8T4224 Washers. 41. Two 8T8911 Bolts. 42. 9G9152 Clip. 45. 3E0461 Control Group.

7. Assemble the sensor control group as shown in the illustration above.

8. Connect the harness to the control connector.

9. Weld 1029550 Plate Assembly (27) to the truck body to the dimensions shown above.

10. Make a 5 mm (.2 in) fillet weld on both sides.

25. Two 8T4896 Washers 33. Two 4L6454 Bolts. 37. Two 6V5782 Bolts. 38. Two 6V8189 Nuts. 40. Two 8T4224 Washers. 43. 1029552 Bracket. 44. 5G7820 Magnet Assembly.

11. Fasten 5G7820 Magnet Assembly (44) to 1029552 Bracket (43) with two 6V5782 Bolts (37), 8T4224 Washers (40) and 6V8189 Nuts (38).

12. Fasten 1029552 (43) Bracket to the plate assembly with two 8T4896 Washers (25) and 4L6454 Bolts (33).

13. Adjust the bracket to get 8 ± 2 mm (.3 ± .1 in) gap.

Transmission Adapters And Valves

1. Remove the step or guard over the transmission controls.

2. Disconnect the cables and remove the existing solenoid valves. Remove the adapters.

3. Clean and stone the entire surface of the manifold. The new adapters will be bolted in a different location, therefore there may be some paint or grease on the manifold under the adapters.

4. Install O-Ring seals, plugs, adapters and solenoids. Refer to SEHS9485 for part location.

5. Connect the wire harness to the solenoids.

6. Remove the cover from the side of the manifold.

7. Remove the existing control switch.

8. Install 6V5828 Control Switch (12), plug the connector in and bolt the cover on the manifold.

9. Remove the existing transmission speed sensor.

10. Install O-Ring seal on the new 3E6955 Transmission Speed Sensor (11) and install the sensor in the housing.

Make sure the tip of the sensor has been extended and that it is installed directly over a gear tooth. Refer to SMHS8617 Installation Procedure.

Tighten the sensor to a torque of 20 to 27 N·m (15 to 20 lb ft).

11. Fasten the existing cable connector.

12. This completes the transmission portion of the EUI Retrofit.

CTS (Controlled Throttle Shift)

Description of Operation

Controlled Throttle Shift controls the engine "desired speed" for a fraction of a second during transmission shifts. In order to do this, the truck must have:

* The EUI engine controller

* The EPTC-II transmission controller

* A working Cat Datalink

Whenever the transmission controller starts to make a shift, it sends a message the engine controller which tells it what the desired speed should be, when it should start controlling to this speed, and when it should end the control. The message depends on the type of shift that is being made.

Determining if CTS is working.

Because the way it has been designed, in general, CTS and the directional shift control will be working properly for all shifts or it will not be working for any of them. The easiest way to verify it is working is to check coasting downshifts described below. If CTS is working for those shifts, it will be working for all others. Because the engine and transmission controls react so quickly, it is difficult to check the other shifts for proper CTS operation without an ECAP tool.

Coasting Shifts

With the brakes and retarder off, CTS tells the engine to speed up every time a downshift is made. To test for proper operation, run the truck up to top gear then allow it to coast back down. You should be able to hear the controller hit the engine accelerate for most of the shifts. Note, CTS has been tuned to be different for different shifts.

If you can hear a throttle increase for any downshifts then CTS is working properly. Depending on the truck model, there will be some shifts where you will not hear a change. This is normal. Also, in order to ensure that the operator always has full control of the truck when trying to slow down, CTS will not operate whenever the parking brake is on, the operator is braking, or when he is operating the retarder. For the same reason, CTS will not operate if any of these brake switches fail.

If you have an ECAP tool set up to monitor engine desired speed, you will see it change from low idle to 1700 rpm for a very brief period during each downshift.

Power Downshifts

You will not be able to hear any difference in the engine for a power downshift.

Upshifts

If you listen closely, you will be able to hear the engine reduce throttle for upshifts. If you have an ECAP tool, you can also see the engine "desired speed" change from high idle to 1500 or 1600 rpm for a very brief period during the shift.

Directional Shift Control

If the engine speed is less than 1350 rpm for a directional shift or a shift from neutral, the shift logic is the same as with previous models. However, if engine speed is above 1350 rpm, then the controllers will drop desired speed to low idle for a fairly long period. You should be able to see this change on ECAP and you will also hear the change in the engine.

NOTE: This test is not recommended unless you have verified that CTS is working before you do it. If the Directional Shift Control is not working correctly, this test will cause high stress on transmission and drivetrain parts.

If CTS does not seem to be working, the most likely cause is a wiring harness or brake switch problem. There should be a diagnostic code in either or both the transmission controller and the engine controller that will pinpoint the area to look for the problem.