Rear End Differences?!?!

[aco1344]

This is my second boxster and the first was a 97' Boxter and this one now is an 02' Boxter S. On my first 97' Boxster with the car on a lift up in the air if I would spin one wheel the other would not do anything. Now on my current 02' Boxster S I tried it and if I spin one wheel the other spins too?

Silly question but what is the difference in the two rear ends? For example this Boxster S, if I'm going up my driveway slow and the clutch is popped it leaves two little skid marks equal length.

[Loren]

Check your Boxster S option codes for M222 or M224 -- both are Limited Slip Differentials (LSD).

[aco1344]

I don't see those 2 codes under the lid but could it be ABS because it doesn't have the PSM button? The reason I is that some say that the ABS acts like a LSD and if so, is there a code for ABS? And I guess another possibility would be some other owner added an LSD since I just bought it a couple of months ago.

[Loren]

If you have PSM then you also have ABD (Automatic Brake Differential). ABD is traction control program which works in conjunction with the new ABS/5 brake system. The ABD is active up to 45 mph. The system applies brake pressure to the rear wheel with the least amount of traction.

[aco1344]

That's just weird then because I don't have PSM.

Just thought the car might have ABD without PSM but from what you tell me it doesn't work like that. One last silly question while on a lift in the air in neutral, while spinning one wheel would the other wheel spin too on an open differential?

[4agdtym]

With both wheels off the ground, typically, when you rotate one wheel by hand, the other rotates in the opposite direction. It is possible for someone to keep one wheel from rotating and the other can be rotated by hand in either direction - the person rotating the wheel will feel the "drag". I think it is just the friction in the diff gears that makes this happen. Even with a LSD, this can happen until the difference in rotational speed between the two wheels meets the point where the diff clutches are engaged - then both wheels will rotate in the same direction.

[aco1344]

I guess but regardless how would it leave to skid marks. I've had open differentials in the past and only the right side would spin. Actually today when getting the front end aligned on the car I noticed while the rear wheels were trying to gain traction going onto the front end alignment lift, the right side was turning and then noticed the left side kick in too and spin. How would an open differential vary the drive wheel right to left or spin on both sides?

[4agdtym]

What you describe is LSD. As you noted earlier, maybe it was installed by a previous owner.

[aco1344]

LSD it must be proving by this pic, lighting em up in the drive way! lol

Must have been installed by a previous owner... I appreciate all the input by you guys! Thx again