Oh The Joy of off roading, ....the fun, ......and the erm.... "Bang" ...... "Gawd - what was THAT ?" Sound(s)
One of these sounds can often be the Crown Wheel & Pinion 'self destructing'. This is not also expensive, but a pig to then fix and time consuming - and just how long will this next one last ?. In simple terms - the more you upgrade your Land Rover ( Bigger tyres, Upgraded Diffs - ARBs, KAMs, True Tracks, Heavy Duty Shafts etc ), the more you "Move" the breaking point(s) around the insides !. One part that many overlook is the is CWP and the casing itself - Its not rare for upgraded CWPs to loose teeth when used hard off road, catastrophic failure of the CWP can quite easily also damage other conponents with the axle, both from the shock loads when things break, and often due to the broken bits getting inside ARBs etc causing seconary and additional expensive damage.
Why do they fail ?. Well, with the massive 'Torque' and / or 'Shock' loadings that can happen off road in a fraction of a second, one of two things can happen. First the Pinion pushes the Crown Wheel away from being fully located, often due to BHP Torque and Grip entering in vast forces into the Differential casing, and 2nd - the diff centre flexes. The pinion teeth then can start to ride up the Crown Wheel allowing the Pinion to spin, disengage just momentarily - and on its return back to re-meshing, takes a selection of CWP and Pinion teeth, and produces an expensive and loud noise - a "Bang" from the Diff and a "Oooer B*gger" from the driver.
"Pegging" the diff Casing holds and forces constant mesh of the Crown Wheel and Pinion by a Phosphor Bronze pad mounted to retain the CWP and Casings in their correct positions under massive shock and Torque loads. This means the pinion cannot now push the crown wheel and / or flex the casing to allow it to break away and do the damage. This is achieved by two 12.9 Ton Special M16 Screws being engaged into 24mm+ of threaded steel plates specially welded (Via a special process which is both complex, expensive and time consuming) to the diff casing, after it is first machined to take the upgrade plating, and the pad adjusted to the back of the Crown wheel. NOTE 24mm + of steel pad. I have "Blown" Pegged diffs in the past, what happened was the CWP Moved, but the "Pad" was only 10mm thick and bowed like a banana and then exploded, hence why 24mm - That 'aint ever going to flex :O)
Once all fitted and the Screws adjusted locating the Pad to the Crown wheel, simply back off a tiny amount, and then lock up solid with the Special Nuts. These cases are supplied with No Bearings, you will need Head and Tail and 2 x Carrier bearing Plus Pinion Seal. They are shot blasted prior to modifications, and the unit comes with detailed instructions for fitting. If you are fitting Larger Crown Wheels some grinding (with nothing more than a 4.25" Angle Grinder ) may be required for clearance at the back of the Diff for the Crown Wheel, and other minor machining may be required for some Diff Lockers.
However, although we can and do supply as a DIY Kit, we do offer a complete building service. We can use many of your existing parts (such as ARB or other special Centres), and your CWP - either Standard 3.54 Land Rover or any of the other various CWPs manufactued in all the various ratios - as the design allows all combinations to fit. We can fit, from Std 3.54 up to the larger and thicker 3.8:1s and 4.75s etc.
Complete DIY Differential kit Exchange with a surcharge of £25 if no casing in return.
Take a Look at our New Differential Information Video Click Here !
For Complete fully rebuilt assemblies to your specification please contact us for a chat and a costing, - its often less than you might think ! - And remember - NO VAT To Pay