Installation of 4P0371 Rear Gear Group{1206} Caterpillar

Introduction

The 4P0371 Rear Gear Group is available for installation as a service replacement for the original rear gear group on the above engines. Before this replacement gear group can be installed; however, it is necessary to do some modification to the 7W4033 Rear Housing that is on the engine.

It will also be necessary to install a new crankshaft seal and seal adapter at the rear of the crankshaft. Part numbers involved for this modification are included in this publication.

This instruction gives the information needed to perform the modification procedure, and for installation of the 4P0371 Rear Gear Group.

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 Book.

Removal and Modification of 7W4033 Rear Housing

1. Remove 7W4033 Rear Housing (1) from the cylinder block, refer to the Disassembly and Assembly section of the Service Manual. Remove the crankshaft rear oil seal and its mounting adapter.

NOTE: Discard the original crankshaft rear oil seal and its mounting adapter after removal because it will not be needed. A new rear oil seal and mounting adapter will be installed at the time of installation.

Use a protective cover for all lubrication oil passages, the oil sump and all machined surfaces.

Modification of 7W4033 Rear Housing (1) will require the use of a portable milling machine, or, contacting a local machine shop to do the necessary machining.

2. Using dimensions (D) and (E), mark the location for hole (A). Use dimensions (C) to mark the location for holes (B).

3. Drill hole (A) to the dimension given in the chart.

4. Drill holes (B) from the outside of rear housing (1). These holes will be through holes (the holes will go completely through this part of the rear housing).

Use a 3/8"-16 2B tap to make threads in each hole (B).

This view is looking inside of rear housing (1).

5. Position the rear housing so the specified inside areas, locations (F) and (G), can be machined. This machining process is necessary to gain the additional clearance needed for installation of the 4P0371 Rear Gear Group.

* Machine (mill) the sixteen bolt hole bosses, locations (F), to a height of 30.0 ± 0.5 mm (1.18 ± 0.02") as measured from the machined surface on the opposite (flywheel) side of the housing.

* Machine oil drip ledge (G) to the same 30.0 ± 0.5 mm (1.18 ± 0.02") height, as shown. This dimension is also measured from the machined surface on the opposite (flywheel) side of the housing. (This ledge provides a deflector ledge for splash oil that drains down the inside of the housing. The ledge directs the oil away from the crankshaft oil seal.)

NOTE: Oil drip ledge (G) is to be machined for a distance of 375.0 ± 1.0 mm (14.9 ± 0.04") on either side of the centerline, dimensions (H).

6. Thoroughly clean the rear housing and flush all oil passages. Inspect the oil passages for cleanliness by flushing them with a clean solvent, then trapping the solvent on a clean white cloth or paper towel.

* If any particles exceed 1.0 mm (0.04") in size, do the cleaning and flushing procedure again.

Installation of 4P0371 Rear Gear Group

NOTE: Refer to the Service Manual for camshaft positioning and any special procedures that may be necessary for installation of the rear gears for the specific engine.

View as seen from rear of engine.

1. Install 4P0374 Shaft Assembly (7). Use four 0S1625 Bolts (14) to fasten shaft assembly (7) to the cylinder block. Tighten bolts (14) to a torque of 270 ± 40 N·m (200 ± 30 lb ft).

NOTE: In Step 2 that follows, left side and right side are determined when looking forward from the flywheel end of the engine.

2. Install idler shafts (16) [7E8411 Shaft (left side) and 7E8412 Shaft (right side)] using four 1A8063 Bolts (17) to fasten them in position on the cylinder block. Tighten bolts (17) to a torque of 475 ± 60 N·m (350 ± 45 lb ft).

3. Slide a 7W7687 Washer on each idler shaft (16), then position a 4P3130 Gear, (5) and (6), on each idler shaft (16). Use three 0S1591 Bolts with 3V3308 Washers to install each 7C6329 Retainer (8) for gears (5) and (6).

Tighten the bolts.

4. Slide a 7E9638 Washer on 4P0374 Shaft (7). Use 1D4566 Bolts (15) to fasten 7E7191 Gear (11) to 4P3128 Idler Gear Assembly (13), then position this gear assembly on 4P0374 Shaft (7).

Use two 3B1915 Bolts to install 4P0294 Retainer (10) on the end of 4P0374 Shaft (7).

5. Install 7E7196 Camshaft Gears (2). Install a 7W5034 Plate (4) and six 1A1135 Bolts (18) for each gear (2). Install a 7W5033 Washer with a 1F6762 Bolt (3) for each gear (2).

6. Tighten each bolt (3) to a torque of 2000 ± 275 N·m (1475 ± 200 lb ft). Use a hammer and strike each plate (4) to seat each gear (2) on the taper of its camshaft, then again tighten each bolt (3) to a torque of 2000 ± 275 N·m (1475 ± 200 lb ft).

* Repeat this tightening procedure until the torque does not change when bolts (3) are tightened.

7. Install new 7E7189 Gear (12) on the crankshaft.

8. Measure and record the backlash for all gears in the rear gear group. The backlash specifications for these gears is as follows:

* 7E7189 Crankshaft Gear (12) to 7E7191 Idler Gear (11), 0.50 ± 0.13 mm (0.0199 ± 0.005").

* 4P3130 Camshaft Idler Gear, (5) and/or (6), to 4P3128 Idler Gear (13), 0.38 ± 0.013 mm (0.0151 ± 0.005").

* 7E7196 Camshaft Gears (2) to 4P3130 Camshaft Idler Gears (5) or (6), 0.45 ± 0.013 mm (0.0177 ± 0.005").

If the backlash specifications are not correct, refer to Step 2. Loosen the bolts slightly and adjust the specific idler shaft(s) (16) mounting position to obtain the correct backlash specification.

Tighten bolts (17) to the torque given in Step 2.

9. When the backlash is correct for all gears as given in Step 8, proceed as follows:

* Using an electric drill with a 6.342 mm (0.25") Ø drill bit, position the drill bit in hole (K) in the right side idler shaft (16).

* Drill a hole in the cylinder block, through hole (H), to a depth of 38.0 ± 2.0 mm (1.5 ± 0.1").

NOTE: Measure from the mounting bolt spot face to obtain the correct depth of the hole being drilled.

* Install a 6V3980 Dowel Pin in the hole just drilled in the flange of the idler shaft.

10. Do the same Step 9 procedure for the left side idler shaft (16).

NOTE: Steps 9 and 10 must be completed before the modified 7W4033 Rear Gear Housing is installed.

After both idler shafts (16) [7E8411 Shaft (left side) and 7E8412 Shaft (right side)] are doweled into position, remove both camshaft gears. The camshaft gears must be removed before the 7W4033 Rear Gear Housing is installed.

11. Install the modified 7W4033 Rear Housing on the cylinder block. Use two 0S1594 Bolts with 3V3308 Washers to fasten the 7E0729 Plate with an 8C3103 O-ring Seal over the newly drilled 98.0 mm (3.858") Ø hole in the 7W4033 Rear Housing.

NOTE: Apply 9S3263 Thread Lock to the threads of all bolts that are installed in the holes with milled bosses on the inside of the 7W4033 Rear Housing.

Repeat Steps 5 and 6 to again install both camshaft gears (2). Again check the backlash between 7E7196 Camshaft Gears (2) and 4P3130 Camshaft Idler Gears (5) and (6).

NOTE: If the camshaft gear backlash is not within specifications, check for correct installation of the camshaft gear(s).

12. Install a new rear oil seal assembly with its mounting adapter for the crankshaft according to the information in the chart that follows.

(19) Adapter assembly. (20) Seal assembly.

* For standard rotation engines, remove the original 7W9022 Adapter Assembly and the crankshaft rear seal from the engine. Install the new adapter assembly and seal assembly given in the previous chart.

* For reverse rotation engines, remove the original 7W8429 Adapter Assembly and the crankshaft rear seal. Install the new adapter assembly and seal assembly given in the previous chart.

Refer to the Service Manual for seal installation procedure.

13. Install all components that were removed for installation of the new rear gear group. Make any adjustments that are necessary.