Installation of Unishaft Drive Line{3253} Caterpillar

Introduction

A single long drive shaft (unishaft) plus extra necessary parts are now available from the Parts Department as a replacement for the existing drive line on the machines listed above.

Installation of the unishaft drive line will offer improved reliability with less parts, and therefore reduced repair costs. The unishaft eliminates the coupling yokes and associated parts.

Do not perform any procedure, outlined in this publication, or order any parts until you read and understand the information contained within.

Reference: Service Manual, Parts Manual, Special Instruction SEHS9138, Tool Announcement NEHG3486 (1/90).

Necessary Parts (without retarder)

NOTE: No unishaft retrofit group is available for the 631D and the 637D Auger type tractor/scarpers.

Installation Procedure (without retarder)

NOTE: It is not necessary to remove the transmission or differential to install the 8X4450 Tube Assembly (23) and related parts.

1. Remove rear guard assembly (belly pan). Remove the existing drive shaft group from the machine.

Drive shaft Group.

Differential Group.

2. Remove the drive shaft enclosure tube from the differential and bevel gear housing.

8X7028 Bearing

8X4450 Tube Assembly

3. Install 8X7028 Bearing (24) in the end of 8X4450 Tube Assembly (23) at location (A).

Install an 8X4452 Ring (27) on one end of Tube Assembly (23).

4. Using a 6V3833 Seal (26) on each end of tube assembly (23), install tube assembly (23) in the differential and bevel gear housing.

NOTE: Lubricate the bores lightly with the lubricant being sealed.

Installation of 8W4730 Drive Shaft Group

Right side view of 8W4730 Drive Shaft Group.

Install the drive shaft group as shown in the illustration using the items listed in the chart.

NOTES:

* Item 15 - Install 2K6073 Bolt and 1B2578 Nut in end of 8W6712 Shaft (15) and adjust the bolt so that the bolt head is bottomed on 8W1490 Shaft (9). Assemble ring behind shoulder on coupling with a maximum clearance of 3.0 mm (.12 in).

* Item 9 - Coat external splines with 5P0960 Multipurpose Type Grease at assembly.

* Items 9 and 19 - Concentricity between pitch diameter of internal spline and large internal diameter of housing must not exceed 3.2 mm (.13 in) TIR (Total Indicator Run out) when assembled. To assure proper alignment, the 4C4566 alignment tool group should be used. Special instruction SEHS9138 provides complete instruction for use. Also Reference tool announcement NEHG3486 (1/90).

* Item 18 - Lubricate bore lightly with the lubricant being sealed.

* Item 22 - Lubricate sealing lip lightly with lubricant being sealed.

5. Install rear guard (belly pan).

Necessary Parts (with retarder)

Installation Procedure (with retarder)

NOTE: It is not necessary to remove the transmission or differential to install the 8X4450 Tube Assembly (20) and related parts.

1. Remove rear guard (belly pan). Remove the existing drive shaft group from the machine.

Driveshaft Group

Differential Group.

2. Remove the drive shaft enclosure tube from the differential and bevel gear housing.

8X7028 Bearing

8X4450 Tube Assembly

3. Install 8X7028 Bearing (21) in the end of 8X4450 Tube Assembly (20) at location (A).

Install an 8X4452 Ring (27) on one end of tube assembly (20).

4. Using a 6V3833 Seal (26) on each end of tube assembly (20), install tube assembly (20) in the differential and bevel gear housing.

NOTE: Lubricate the bores lightly with the lubricant being sealed.

Installation of 8W4729 Drive Shaft Group

8W4729 Drive Shaft Group.

Install the drive shaft group as shown in the illustration using the items given in the chart.

NOTES:

* Item 4 - Coat external splines with 5P0960 Multipurpose Type Grease at assembly.

* Item 4 and 14 - Concentricity between pitch diameter of internal spline and large internal diameter of housing must not exceed 3.2 TIR (Total Indicator Run out) when assembled. To assure proper alignment, the 4C4566 alignment tool group should be used. Special instruction SEHS9138 provides complete instruction for use. Also Ref. tool announcement NEHG3486 (1/90).

* Item 13 - Lubricate bore lightly with the lubricant being sealed.

* Item 19 - Lubricate sealing lip lightly with lubricant being sealed.

5. Install rear guard (belly pan).