busted rear diff - still drivable?

Submitted: Monday, Oct 13, 2003 at 22:11

ThreadID: 7802 Views:2379 Replies:2 FollowUps:4

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KG

I'm a little vague on diffs and 4wd operation... I think I know enough to be dangerous...
Yesterday we were up at Mt Mee when a mates bronco busted it's rear diff... we ended up pulling the tailshaft and pinion out of the rear diff and drove it home locked in 4wheel drive (now front wheel drive)
It went ok until it came to go up a hill - weight transfers to the rear and the fronts just spin... snatching that huge lump of ford uphill was a neck stretching experience. later that night we ended up back on the bitumen and limping our way back to brisbane.
anyway.... it got me thinking about diff windup and diffs sending power to the spinning wheel and all sorts of things...
can someone pls put my mind to rest in relation to open centre diffs, closed centre diffs (what *is* a centre diff? the transfer case?) and why we didnt notice any diff windup on the bitumen when limping home?

cheers,

KG.

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Reply By: Member - Ross- Monday, Oct 13, 2003 at 22:26

Monday, Oct 13, 2003 at 22:26

Constant 4WD such as Landrovers and Toyotas as well as ordinary AWD road cars have a centre diff to allow the front wheels to turn at different circle radii than the rear wheels to avoid diff windup, which you would get with the older style when you engage 4WD without the 3rd (centre) diff and drive on hard surfaces which do not allow any wheel spin. As against the transfer case which all 4WDs have to "transfer" the drive to both axles.

When you removed the tailshaft etc from the rear diff you effectively took the back axle out of the equation and ended up with a front wheel drive vehicle (more or less) .. hence no diff windup. All the back axle did was stop your bum dragging on the ground.

Q.E.D.Rosco

AnswerID: 33665

Follow Up By: Member - Ross- Tuesday, Oct 14, 2003 at 08:04

Tuesday, Oct 14, 2003 at 08:04

PS
The 3rd diff hangs off the gearbox, along with the transfer case.Rosco

FollowupID: 24203

Reply By: Rob from Cairns Offroad Training & Tours - Tuesday, Oct 14, 2003 at 08:16

Tuesday, Oct 14, 2003 at 08:16

Try this site for further info and diagrams http://auto.howstuffworks.com/four-wheel-drive.htmCairns Offroad Training & Tours

AnswerID: 33694

Follow Up By: Member - Cocka - Tuesday, Oct 14, 2003 at 21:40

Tuesday, Oct 14, 2003 at 21:40

Rob I also subscribe to the HSW site. There's some great information there about all manner of things.Carpe Diem

FollowupID: 24284

Follow Up By: Member - Cocka - Tuesday, Oct 14, 2003 at 21:43

Tuesday, Oct 14, 2003 at 21:43

Rob I also subscribe to the HSW site. There's some great info there about all manners of things.
It might have been you that put me on to the site a while back.Carpe Diem

FollowupID: 24285