limited slip jag rear suspension

malibujohn · #1 (**permalink**) 09-25-2002, 10:25 PM

Is there anyway to tell if the Jaguar differential has limited slip when inpecting the outside of the unit or do you have to break it down.

malibu

Excaliber · #2 (**permalink**) 09-25-2002, 11:39 PM

Jack it up, back wheels off the ground. Spin one rear tire by hand. The opposite tire will spin in the opposite direction if it is an "open" rear. If it's a "posi" unit, the opposite tire will spin in the same direction OR will NOT spin at all! If ONE brake is dragging even an open wheel rear may APPEAR to be a posi. The way to simulate "posi" when your "stuck" for instance is to APPLY the brakes gently while giving it throttle!

Also, it will take more effort (muscles) to spin one tire by hand. This is tricky to tell though. Might be brakes dragging for instance. There is a "break away" force that can be measured and it actually has a "spec" in lbs force. How much "force" it takes to start the tire spinning due to the extra tension on it from the "posi" unit. An open rear takes VERY LITTLE effort to "break away" and start spinning by hand. A posi takes noticably more force to spin by hand.

Ernie

mickmate · #3 (**permalink**) 09-26-2002, 07:43 AM

The Jag rear has an aluminium tag on a back cover bolt that gives the ratio. If it is the limited slip it will have a second tag saying so. The previous post gives good clues on checking depending on if it's in the vehicle. It's only a matter of minutes to pull the back cover anyway. There are alot of options available for converting on open rear to a limited slip diff. I'm investigating them at the moment.
It would be nice if there were a bunch of Jag's with 3.54 powrlok's laying around.........
Cheers Nick

ulwe · #4 (**permalink**) 09-29-2002, 12:24 PM

I beleive that limited slip units were mandatory in the V12:s and only optional in XJ6, and therefore its easy to find Lim. slip units with 3.00 and 3.31 ...... and more seldom these with 3.54, but Im happy with mine driving in the streets, and with an Ford AOD gearbox, life is easy on the highway!

Ulf

Excaliber · #5 (**permalink**) 09-29-2002, 12:39 PM

ulwe,,,that is correct. And I always hated the high rear end ratios typically found in the XJS cars (but I love those cars)!

Ernie

Vision · #6 (**permalink**) 09-29-2002, 08:13 PM

here is another way similar to the first, just jack one wheel off the ground and put in neutral. spin or attempt to spin the wheel off the ground. if it spins with realitive ease it has open spiders, if it is hard to turn it would indicate a limited slip, if it turns 1 rotation or less and is unable to be turned anymore it is probally a posi.
hope this helps and it works with just about all makes.