4WD - Off Road Flashcards
Outline basic 4WD system (diagram)
- Front diff
- Hubs
- Front drive shaft
- Engine
- Transmission
- Transfer case
- Axles
- Rear driveshaft
- Rear diff
When to engage 4WD?
- When likely to lose traction
- Loose or slippery surfaces
- Maximum traction required
- Negotiating difficult terrain
What does transfer case do?
It’s an additional gearbox that allows the driver to select different ratios and change between two- and four-wheel drive
3 questions to ask yourself before planning to use 4-wheel drive?
- Do I have to go there - can I get back?
- Is the vehicle capable of going there?
- Am I capable of driving the vehicle there?
What is conducted in a Daily Check?
- Leaks
- Body damamge
- Tyres
- Fluid levels for clutch, brake and power steering
- Oil level
- Coolant level
- Water level (Windscreen)
- Battery terminals are tight and clean
- Windscreen and mirrors
- All lights
- Beacons and sirens
- Fuel level
- Firefighting equipment
- Inventory
What is maximum safe angle when cross slopes?
13 degrees
What is the vehicle rollover point?
25 degrees
What is the stall stop procedure - manual?
- Ease off accelerator
- Apply foot brake
- Allow engine to stall
- Apply handbrake
- Check of vehicle is clear for decent
- Gently push in clutch (let clutch out if vehicle roll back)
- Engage reverse gear and release clutch
- Release hand brake and slowly ease foot off brake
- Start engine and control the decent
What is the stall stop procedure - auto?
- Apply foot brake and handbrake
- Check vehicle is clear for decent
- Foot still on brake, select “N” neutral
- If engine has stalled, start in ‘N’
- Select ‘R’ reverse
- Release handbrake
- Gently ease off brake, keep pedal ‘covered’
- Begin descent
2WD pros and cons (1 each)
Pro - Good turning ability
Con - Does not have good traction
4WD pros and cons (1 each)
Pro - Good traction due to 25% at all wheels
Cons - Large turning radius
What is Limited Slip Differential (LSD)
LSD reduces individual wheel spin but allowing some power to go to the wheel with traction
What brake should always be engaged before going down a hill?
Exhaust brake
