Thread: **TD5 Def - BLOWN DIFF**

seems to happen a bit.
Cross pin hole flogs out in the hemisphere. A four pin diff (Rover or Jac Mac), a Maxi, a Jac Mac locker, an ARB, or a Tru Trac will also eliminate this happening again.

Rick

Is this the same case for the rear?? So it s not an abuse thing then? More a wear issue? Could it be the circlip even???



Mike

We had two front diffs go last year while heading to and returning from the Madigan Line - Simpson Desert.
In each case the cause was the bolts securing the crown wheel becoming loose (they are only loctited these days instead of as with the Series vehicles being wired together). Movement between the C/W and hemisphere then causes a bolt head to shear off, whch then gets mixed up between the C/R and Pinion - or maybe some other moving parts.

In both cases the vehicles had, at some time in the past, been driven for a few hundred kms on the front diff only - due to some failure in the rear drivetrain - broken axle or drive shaft uni joint.

Has your's ever been driven on the front diff only?

Roger

It is dangerous... I drive home from land cruiser mountain park with the same broken cross pin and spat gears... drove around for a week before i heard a few worse clicking sounds... pull the centre out to find alot of peices... lucky it never locked up.

My second event similar to this was after I knew I had broke the front diff, was limping home slowly (was only about 5ks from shed) and just as I pulled up the gutter infront of the shed... BANG locked up... it was the bump of the gutter that gave it that little bit of gear it needed to lock up... Def not something I would like to happen at 60ks.

Both therse instances were in rangie classics, but are very similar to the front diff dramas I have seen in all defenders.

Everytime the cross pin fails, gears all stay in place, until excess load or shock is applied then it gets worse and worse.

I had one rear diff blow a cross pin and some how the pin got outside the hemisphere without doin any damage to the differential what so ever...

And only just a few weeks ago I took my rangie out to ormeau and spat the cross pin through the bottom of the housing. (havvent opened that onbe up yet to check otu the gear damage.

blablabla

Moral of my story... rover diffs suffer from the weak single crosspin design. Couple with too much flex from the hemispeher... solution = ARB, Jack Mac, or MaxiDrive (second hand) lockers front and rear

Originally Posted by Xtreme

In both cases the vehicles had, at some time in the past, been driven for a few hundred kms on the front diff only - due to some failure in the rear drivetrain - broken axle or drive shaft uni joint.

Has your's ever been driven on the front diff only?

Roger

My last breaking of the front diff in the post above was drivin in front wheel drive only from The springs 4x4 park to aratula about four months earlier, so this may have contributed.

Loctite should be fine, if the right grade is used and it's applied properly.

I've rebuilt a few diffs, mostly race cars and we never wired the CWP bolts, only loctited, and they were all fine. The first race car diff I rebuilt was under the guidance of a NASCAR and touring car mechanic (and ex-aircraft mechanic), and he only used loctite, too.
Yes, wiring bolts is still used in critical applications in aircraft, and you can wire the diff bolts if you like, but drilling bolt heads in high tensile bolts is painful (been there, done that, even made a jig to make it easier) and I'd still use loctite instead of wiring because

a. I don't have wire twist pliers
b. I've never been able to do it near as neatly as the blokes I know that work on aircraft

Ring Ian at MTE 4X4 in Morwell.
He's probably got a c/o one sitting on the shelf.

Cheers on the tips lads,

Rover towed the Defender on Friday pm (to the wrong dealer however!). Dealer reckons 1 MONTH to do the job!

So...will have to keep hassling them...


Mike