4HP20 Gearbox Rebuild

 

Introduction

A pictorial of a 4HP20 rebuild


Output bearing carrier

Installing the output bearing carrier. Note tape wrapped arounmd socket to avoid any damage to the F piston bore.

Tigentening the screws

Tightening the bolts. 35N/m Torque.

F Piston Install

Installing the F Brake Piston

F Brake Diaphragm

F Brake Diaphragm Spring

Compressing the F Spring

Compressing the F Diaphragm Spring

F Brake Retainers

Fitting the spring retainers

Diff and Intermediate gear

Diff and Intermediate gear fitted

Park Pawl

Park Pawl mechanism

F Brake Plates

F Brake Plates 

F Brake Drum

F Brake Drum

Gaskets

Gaskets fitted

Oil Pump

Oil Pump installed

Torque Oil Pump

And torqued up

Oil Filter

Oil Filter Installed

All together

Housings joined and bolted up

Seal Tools

Special tools to Install Diff Seals

And home

Just before being tapped with a mallet to send seals home

OSS Clearance Cleck

Checking the Output Speed Sensor clearance to the output gear (Sensor installed temporarily)

D Piston

D Brake Piston installed

Wavy ring

Followed by the wavy ring

D Brake Compressing

Depressing the D diaphragm spring to allow the D brake to disassembled

CD Brake Install

Installing the C and D Brake pack

C Piston

Followed by the C Brake Piston

Snap Ring

And the Snap Ring

Outer Annulus

Installing the epicyclic outer annulus

Inner Annulus

And the Inner Annulus, Planetary Sun Gear set

Planetary carrier

Planetary Gear carrier and Snap Ring

Input Shaft

Input Shaft and B/E Clutch Assemblies

B/E bearing And Spacer

Showing the order of the B/E Clutch Spacer and Bearing that controls Input Shaft End Float

Transmisson Cover

Replacing Transmission Cover

Checking End Float

Checking the Input Shaft end float

Oil Pan magnets before cleaing

Oil Pan (Valve Block Cover) Swarf magnets before Cleaning

And After

And After!

Output Speed sensor Installation

Output Speed Sensor Installation

Valve Block

Valve Block Installed

And Torqued

And torqued up

Kostal Socket Clip

The KOSTAL socket clip installed

Multi Function Switch

Multi Function Switch

And finally.. The Vehicle Speed sensor

VSS

Job Done!

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Page last updated 06 November 2009