Gearbox (Transmission) - Task No 8 - Monday 2nd March 2015

Gearbox Removed

Plan:  

Gather tools, equipment and vehicle information.  Dismantle Gearbox and lay out in a logical sequence ready to analyse and diagnose.  Analysis to include:

• Identification of Components.
• Gears and Power Flow.
• Selectors.
• Bearings.
• Listing of Faults.
• Calculate Gear Ratios for all forward and reverse Gears (within Portfolio).
• Complete Knowledge Questions (within Portfolio).
• Account for and clean all tools and equipment.
• Complete Blog.
• Report to Assessor to deliver Analysis and Diagnosis.

Task Progression:

Dismantle Gearbox:

Dismantled Gearbox

Identify Components (extensive ID provided within Portfolio):

Selector Forks

Layshaft (Countershaft)

Detent, Retaining Spring and Cap

Mainshaft to Input Shaft (& Isaac's Hand)!
Selector Rod to Rear

Analysis:

• Chipped teeth on all gears on Mainshaft and to corresponding Layshaft.
• Input to Main Shaft Spiggott Bearing Absent.
• Baulk Ring absent from 3rd/4th Syncro Hub Selector.
• 3 Slippers absent from 3rd/4th Syncro Hub.
• 2 Slippers absent from 1st/2nd Syncro Hub.
• Detent Retaining Spring distorted.
• Detent Screw Cap partially stripped.
• Extension Housing securing bolt fixing point snapped and absent.
• Extension Housing End Oil Seal Absent.
• Layshaft Spacer Sleeve Absent.
• Input Shaft Bearings corroded.

Absent Slipper & Baulk Ring

Evidence Chipped Helical
Gear Teeth

Evidence
Corroded Bearings

Diagnosis:

Due to the age of the unit, the extent of the visible damage to the various gear teeth, and also the level of absent components, I would estimate that this gear box is beyond economical repair.

Calculate Gear Ratios:

Detailed calculations provided within Portfolio (Driven over Driver).

1st   3.656:1
2nd  2.184:1
3rd  1.425:1
4th  1:1 Direct (locked to Mainshaft)
Rev 4.235:1