A manual ASD install would be possible for someone experienced and knowledgeable but not an easy job. I know in the factory installation it is powered through the OVP (asd cars tend to have a different ovp relay); also there is a switch on the brake pedal which activated and presumably cuts out the ASD operation for some reason.

Have a look a the video I posted on the first page to see it in action. You don't strongly notice it activating. The only time I notice it is if it's wet and I pull away at speed inducing wheelspin. When you hit a certain speed (19mph by the looks of things) the acceleration occuring can reduce - this is I presume due to the ASD cutting out and me being left with less rear lock up and less traction.

In the dry, in bends, and making a tight turn while pulling away, I don't notice it operating, so either it's quite subtle, or the existing LSD effect is making a good difference already, or my clutch packs are worn out.

Incidentally my ASD diff has slack in it and makes the drivetrain clonky; is it rebuildable and could I do it myself?

In LSD work I've done, I was able to specify how much lockup (what %) I wanted, I've gone up to 60% for some racing applications.

Dave or others might know if the parts are available to create a tighter rear diff for these cars also, I'm guessing yes. Looser also.

The clutch pack is rebuildable, and is an "advanced" DIY if you're willing to tackle the job. If the diff itself is worn (bad bearings, or gears, etc)... forget it, much easier (and cheaper) to replace with a good used diff.

Nope, not with the Mercedes design. If you try to make the clutch pack tighter, you cannot assemble the diff (the spider gears will not rotate into position). BT, DT. When set to spec, it immediately (within 100-200 miles of driving) wears enough to allow turning left vs. right sides by hand. It only offers the ~35% lock when under load (torque applied from engine to the wheels), this puts presure on the clutches and causes them to engage.

You can add a spring block, which adds pressure to the clutch pack at all times. This basically simulates ASD engagement at all times. You adjust the "percent" lockup by stronger or weaker springs. The only drawback is that you cannot use circlips to hold the axle flanges in place, they will float in & out. The folks who have done this (usualy the 190E-16 crowd) say it works ok though. For street use, I have not found it necessary to do this. I'm sure on the racetrack (road course or autox, not dragstrip!) it's a bigger deal.


:hat:

Let's hear more about the rebuild..... :)
Can it cure looseness in the diff? Cure jerking at low speed and changing gear?

The rebuild is pretty straightforward, and covered in the factory service manual (the W126 manual has really good photos of the procedure). If the diff is "loose" as in sloppy, meaning excess gear backlash, or bearing movement... that's when you replace the entire diff with a good used unit. The clutch pack rebuild ONLY will improve the limited-slip action. When the clutch pack is worn out, the diff acts like a plain open diff. Rebuilding the clutch pack restores the limited-slip functionality only.

Jerking at low speed and/or when changing gears sounds like a tranny issue, or flex disc problem, and if it is the diff... again, that sounds like a worn-out differential. A tired LSD clutch pack would not cause any of that behavior, it simply wouldn't provide any connection between left & right wheels.

:blink:

Okay... well that's what I have, a jerking. Flex discs are (were) new and gearbox was rebuilt so I presume is fine, which brings me to the diff. You can't rebuild the part of the diff that makes it jerky then? Replace the worn gears or something??

Change the fluid, be sure you have the correct fluid for LSD.

Really? Fluid??

Why not? It's an inexpensive place to start.

^^ my opinion also.

LSD doesn't work properly with additives and such, if you don't know what's in there, it's a good place to start IMO.