Transmission terminology

2. Why do we need Transmissions?
 To change the tractive
force to the drive axle
 T.F. Engine=torque X Gear Ratio
 Keep engine in the Power
Curve
 Increase fuel economy
 Match the need/use of
the vehicle

3. Transmission Types
 Front wheel drive
(transverse)
 Reduces vehicle weight
 Allows more interior
room
 Places weight over drive
wheels
 Compact design
 Is called “Transaxle”
because it transmits
power 90deg to engine.

4. Transmission Types
 Rear wheel drive
(longitudinal)
 More robust
 Easily modified for
accessories
 Rare in passenger cars
today

5. Transmission Types
 All Wheel Drive / 4
Wheel Drive
 Applies torque to all 4
wheels
 Can be “Automatic” or
“manual”
 Uses Transfer Case to
deliver power to non
driven wheels

6. Final Drives
Solid/Live Axle Integrated/Dead Axle

7. Transaxle Types
 Simpson gear set type
 Uses clutches & Bands
to hold and drive
different planetary
components
 Most common type

8. Transaxle Types
 Gear and Clutch
 Manual trans type
gear train with
clutch packs to
engage gears
 Typical for
Honda/Acura and
Saturn transaxles

9. Transaxle Types
 Belt and Pulley
 A common CVT design
used by Honda, Ford,
GM and many other
Mfg.’s
 Most “pull” belt but
Honda “pushes” belt
 Nissan CVT

10. Transaxle Types
 Dual Planetary
 Used by Toyota in
hybrid vehicles
 Very simple to
build…hard to
understand at first
 Honda using similar
design in 2014

11. Transaxle Types
 DCT Dual Clutch
Transmission
 Has gears and forks like a
manual transmission but
each shaft has a separate
clutch
 Allows for very fast gear
changes

12. Transmission Types
 GM RWD hybrid
transmission
 Simpson planetary
design
 Uses 2 motor generators
for power/regen.
 Has 12 pump to keep
clutches applied during
engine off stops/takeoff

13. Safety Precautions!!!!
 Anytime you service
Hybrid Vehicle you
MUST GLOVE UP!

16. 3 Phase Cable
Indexing.

17. High Voltage DC Cable routing.

19. 6 Bolts to remove Valve
Body and TCM

20. Gear Selector Positions

21. Gear Position
 Park
 Engages park pawl to prevent vehicle movement
 Many times you have to step on brake pedal to shift out of
park
 Shift Interlock
 Reverse
 Applies clutches and bands to move vehicle backwards
 Park pawl released
 Neutral
 Park pawl released, bands/clutches not applied
 You can’t tow a automatic in N because of lack of lubrication

22. Gear Position
• Overdrive / Drive / Third
 Allows for automatic shift
form 1st to hi gear
 May have OD switch to Lock
Out high gear and allow
engine braking
 Second
 Allows upshift form 1st to 2nd
only or locks in 2nd
 Allows engine braking

23. Gear Position
 Manual Low / 1st
 Lock in low gear
 Allows engine braking
 Many times applies
additional band/clutch
for additional load
’64 Dodge Wagon