Building a Sierra Driveline for Victorian Conditions

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Greg
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Joined: Tue 16 Oct, 2007 5:49 pm

Building a Sierra Driveline for Victorian Conditions

Post by Greg »

Building a Sierra Driveline for Victorian Conditions

We had a few questions at the meeting last night from new members looking to turn their stock sierras into off road performers in a minimal number of steps.

Here are the steps that were discussed. Hopefully this should be a good starting point.

Notes:
1. These stages are aiming for a 31 to 33” tyre. For bigger tyres like a 34 or 35, I have added a few notes.
2. This topic is driveline only - the steps you take to clear your tyres are a whole different topic. We will cover that elsewhere.
3. My theory is – Spend it once, Spend it right. Some of my suggestions are expensive – but they should ensure you never have to do them again.
4. Trail Tough are not the only people that sell this stuff, but I have dealt with them quite a bit and highly recommend them.

Step 1:
Take the doors and roof off your car. This will instantly transform the car into an off-road weapon!

Step 2:
Pick your tyre. As stated above, let’s say you are aiming for a 31 to 33 inch tyre.
Get your rims to match. Think about if you are going to run beadlocks (weld in or pre-made) before you buy your rims.
Do not put your tyres on until you have your gearing sorted.

Step 3:
Gear your car. Transfer Case gearing is a quick and simple method.
Example of Transfer Case Gears:
http://www.trailtough.com/index.php?pag ... &Itemid=53
Go for the 6:1 or 6.4:1 – you can always grab second or third if you can’t generate the wheel speed you want.
Your car is now ready to drive. It will have heaps of gears and you will love how slowly and controlled you feel when driving off road on anything that you can get traction on.
You might want to get your transfer case rebuilt with new bearings and seals. No point putting new gears in with old bearings.

Step 4:
Lock it up! Now that you have the gearing, your car is ready to take on the extra traction that lockers will provide.
Rear first for maximum gain, front second to complete the setup.
The end result to aim for is an air locker front and air locker back. If you can’t afford that, then aim for airlocker front and spool back.
If your car is your daily driver, you might aim for air locker back, until you can afford to air locker the front too.
Example of Air Locker:
http://www.trailtough.com/index.php?pag ... &Itemid=53

Remember that the air locker will come with an Air Compressor for turning them on and off.
Example of Air Compressor:
http://www.trailtough.com/index.php?pag ... &Itemid=53
Note that they come in 3 sizes so you might want to spend a bit more here to get a good result for tyre inflation later on:
1. Very Small – only useful for running air lockers
2. Medium – good for air lockers and slow tyre inflation
3. Big – good for air lockers and rapid tyre inflation

Example of Spool:
http://www.trailtough.com/index.php?pag ... &Itemid=53

When you are sorting out the front end, it is advisable to put a 26-Splined Air Locker in. This will allow you to step up to Double Tough axels.
Example of Double Toughs:
http://www.trailtough.com/index.php?pag ... &Itemid=53

When you are installing a locker, it is advisable to replace the crush sleeve with a solid spacer. You will need a professional to do this work for you. The crush sleeve will ensure that the pinion and crown gear cannot ‘walk’ on each other. This will make for a tougher and longer lasting setup.

Note for Bigger Tyres (34 – 35inch):
Before spending money on Lockers, at this point you should be thinking about a few options:
1. Changing the diff gears (save money by having your locker and diff gears installed at the same time)
2. Building a full floater rear diff rather than spending money on your sierra rear diff

You now have a sierra that will drive almost everything in Victoria, your engine is still completely stock and (hopefully) as reliable as the day you bought it.

Next steps – suspension changes, power steer, gearboxes and engine swaps.
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