Oh wow. You are in luck! Converting a 400E without ASR, to 2.82 limited-slip, is about the easiest swap possible. The S350 diff (with optiontal ASD) has the correct input flange, gearset, and housing. Basically you swap the output (axle) flanges by removing the ASD cylinders, and installing the flanges from your current 400E diff (replace the seals while it's apart). Then swap the rear cover, clean it up, fill with 1.3L of LSD-compatible gear oil, and bolt it in. Just make sure you ask the salvage yard with the S350 for the VIN, look up the datacard in the EPC, and make sure it has option code 211 (ASD).

Now, as mentioned before... the clutches on a used S350 ASD diff are likely to be pretty worn. You can either take a gamble that they still have some life left in them, and try it out... if there's not enough locking action, you'll need to take it all apart again to replace them. Or, you can just plan on refreshing the clutch pack at the same time you're swapping the flanges & cover. Figure $300-$400 in parts for the refresh, you'll need to make some tools, and figure out how to do it... not terribly hard but the first time took me forever because I didn't know what I was doing. My second attempt went about 10x faster. The W126 service manual has a really good procedure, job # 35-550, which details how to take the diff apart to get the ring gear + carrier out so you can then disassemble it to replace the clutches. Then, job # 35-560 shows how to take the carrier apart and replace the clutches. Forget the 124 service manual for this work, it's not nearly as clear.

Oh, and be careful with the ABS sensor... you may need to swap that also, and they can break if you're not careful removing it ($$$).

For a car with ASR, this won't work, the housings are different. My E420 has ASR, so I have to do it the hard way if I want to add limited-slip).




Best regards,

 

You don't need any special tools for the job...

 

That depends on your definition of "special", and also how extensive your personal tool colleciton is. It also depends if you are changing the input flange on the pinion or not... if so, then yes, special tools ARE required - to do it right, anyway.

 

That's good news, so please tell us how without special tools. Step by step. Please share your knowledge and contribute to this forum. I need to do ASD diff work soon.

Thanks.

 

I assume you mean if you are just taking one diff out of one car and putting the same exact diff in another car.

If its anything more involved then it depends on how extensive your collection of tools is, and how adequate your ability is.

 

Right, my "personal tool collection" is really extensive...

Normaly you needen't change the pinion or the input flange, cause they are mostly ok.

You yust change the 6 bearings and sealings.

In my ALSD I just replaced the stuff shown on the pictures below.

You just need some normal tools like wrenches, hammer and chissel for changing the bearings, a flex and and of course i used a few extractors to bull some of the bearings off, but you can also use a flex for the job.
The new bearings can be mounted by hand if you put them on a cooker, before. You may have the right big nut for the front screw nut.

The setup of the clearance can be made by feeling.

You don't need a tool for reading the pinion friction moment, because the min was by ca. 40NCM and the max at 100ncm, i think, so thats what you can feel with your hand.
You also needn't a mounting plate, yust put it on the table.
You needn't a tool to pull out the circlips, you just can use a wire or a gripper.
Instead of a Puller, you can use a hammer and chissel to pull out the driveshaft center support bearings out of the body and to pull the new one in. You just mustn't hit the bearing surface...

Right here, you can see my story of rebuilding my diff, sorry, but it's in german and it can be that you must register before you can see the pictures: http://www.mb-freunde.de/vbulletin/s...ead.php?t=3695

 

Dave,

I got a diff from a S350 with ASD, no ASR. I had my buddy check the vin, and according to the vin, the car was a 1994 S350, ASD, no ASR. The diff has the ASD plumbing and axle flanges. So everything looks right, except when I turn the output shaft. This diff does not behave like any diff with an LSD carrier that I have experienced in the past. If I hold the input shaft from turning, and turn one of the output shafts, the other output shaft rotates in the opposite direction, just like with an open carrier. I know the clucthes could be worn, but even if they are toast, under no load it should still lock up. Did I get an open carrier? Am I missing something? I haven't removed the ASD flanges yet, but I can't wrap my head around that being the issue. Can you enlighten me?

 

Hi again,

Short answer: That's normal - nothing to be concerned about.

Long answer: I found the same thing when I got my ASD diffs. At first, I assumed this meant the clutch pack was shot. After replacing the clutch pack, it was TIGHT, I couldn't hold one axle flange while turning the other by hand. AH, much better, right? But after only 100-200 miles of driving, it was back to how it felt before! I could turn one rear tire by hand and the other tire would turn the opposite direction, just like an open diff. However - the difference is, with LSD / ASD, it takes a noticeable amount of additional effort to turn the flange (or tire) by hand, compared to an open diff. That's due to the clutch pack - even though it's not locked, it does create *some* resistance.

Despite how it feels by hand, the LSD function does work fine when driving (assuming the clutch pack is not excessively worn). The reason is, the Mercedes LSD design requires torque input, and load applied, to compress the clutch packs. My buddy at the dealer (who has done many LSD rear ends) explained this to me, and although I was skeptical, my hands-on experimenting proved he was correct. The bad news is, there's no way that I know of to reliably check the clutch pack condition (on an LSD diff) without driving the car to test it out (or, tearing it apart & measuring the wear on the clutch discs). Note that on vehicles with ASD, there is a procedure to measure via torque wrench, but that's not possible with plain LSD.

So, you're back to decision time... either bolt the used diff up and hope the clutch pack is ok, or just tear it all apart and spend the time & $$$ now, before you install it in the car.

 

Thanks, that makes me feel alot better. I was worried that it was the wrong diff even though all of the number said otherwise. I am going to bolt it up and see. It's not that big of a deal to drop it back down later, and I don't have the cash or the patience to wait at this moment. If it's worn out, an open 2.82 is gonna be a bunch more fun than an open 2.24. Thanks for all of your responses. Your knowledge and experience is uber-helpful.

 

Hi AMG Dave The part converting the 185 ASD to LSD is very tempting if
it means*just changing the output flanges* and maybe the input flange
if isn't the right size . I am having the option for a W 124 E 320 Auto 3.07
ratio with ASD that I would like to take place in my C 43 AMG .

IF,, I can do that without complicate things by also build some sort of
hydraulic system to activate the ring-cylinders manually , and * just *
re-load the carrier with new friction discs and adjust the preload . WOW

In this case ( the C 43 ie ) I do not even have to care about ABS because
the diff casing is * clean * no sender's as they by MB then wisely were located
in the wheel carrier's . Unfortunately this is not applicable on the ASR
equipped car's .

The 210 mm Big diff housing as on my 500 E needs another conversion as you
say here and in 500Ecstasy namely the W 126 LSD carrier ...Period

Thank you Dave for your work and for showing , by now I'm convinced and
see the W 140 2,82 ASD as a dead end street , too elaborate to convert .

About the * feeling of an open diff * as mentioned in this thread and the
locking action under power must be the effect of the pressure the diff.carrier gears
have on the side gears as they under power * ride * on the side gears and
pushes them outwards to further pressurise the clutchpack. You can say
it has some kind of * power lock or positraction * not only working by
it's preload . Thanks again Dave . Roger

 

So now that I have the ASD diff with the cylinders and plumbing, I am thinking about what TaxiDriver said above. Would it be possible to leave the ASD in tact and manually activate the line pressure to it with a solenoid valve. I would have to get the correct powersteering pump for a M119 with the dual pump. The axle length would have to be the same, and the actuation of ASD would have to be an on-off operation. Would this work? I'm gonna take some measurements on the axle flange spacings today if I can get the car on the lift. It would be cool to have lockup on demand. I have no clue about the ASD system and if such a mod would be feasible.

 

Hi dernt , There are what I think Two ways to make use of the ASD in a
car that didn't have it from new . Either convert it to LSD as Dave did
Or like in the thread of 500Ecstasy.com Limited slip or not , matsalle76
wrote about one ASD with a manually operated system , http://www.500ecstasy.com/forums/att...5&d=1236109861
I would myself if possible go converted 185mm ASD for my W202 C 43 . Roger

 

Yes, you could install a "manual" ASD into a non-ASD car, with a switch on the dash to engage it. However, it may not really be necessary, unless you find that the normal 35% lockup is not adequate. The one nice thing about ASD is that it will still get decent lockup as the clutch pack wears, by exerting additional pressure on the clutch pack, compared to plain LSD which relies totally on the force applied by the side gears.

Another option to increase lockup is to install a spring block between the side gears, like Kleeman or PhantomGrip, which sort of simulates ASD engaged all the time, and can be adjusted slightly by using stronger or weaker springs. The drawback to this method is first that nobody currently sells a kit for MB LSD or ASD, so you'd have to have something custom fabricated; and second that you cannot use the circlips which lock the axle flange into the diff - the axles will always float in & out. A few people have done this (mostly the 190E-16 crowd) and say it works ok, but I still don't like the idea of not having the axles fastened into place.

 

Taxi Driver, Yeah, that is what I had in mind. The axle length is going to make the difference. I think it is going to require custom axles, or a bunch of hunting and measuring.

It would be neat to install a set of manual pedals and hook the clutch pedal up to a clutch master cylinder. Then use the pedal to apply pressure. Gotta think about this a bit more, but in the mean time, I think I will do as AMGDave suggests: I will just remove the ASD, save it, and see if the LSD satisfies me.

 

Hi,
I do not understand, why the simple spring method between the side gears is not good?
Maybe someone could describe it to me in simple english Thanks in advance
Rod

 

Hi , Dave do you happen know the diff brake action percentage in the
ASD and how much operating pressure it has ?

If it's possible to set the ASD to LSD preload and then have the ability
to almost full lock if needed by operating the ring cylinders manually ?

To have a Manual Sperr Differential MSD that would be nice occationally
maybe operated with compressed air ? I don't know just a thought.. Roger

 

Roger, when the ASD is engaged, it has nearly 100% lock when the clutch pack is new. As the clutch pack wears, this percentage will drop. I do not know what the hydrualic pressure is, but I suspect it's relatively low.

You could set up a "manual" locking diff using various methods (some are mentioned earlier, IIRC) but I still don't think you'd find much use for this. In a straight line (i.e., launching the car) you don't need a lot of lock. On a racetrack (road course), you don't want too much lock or it will cause erratic handling under hard cornering (possible oversteer).

For most applications, normal LSD is usually fine, perhaps adding a spring block if you *really* need additional pressure.

 

I think it has a 100% lock by 100NM.
If you make more NM, it will slipp.
When it is older, it may slipp at less NM, fex. at 80 or 60NM.

The Spring idea can work. But you has also to install a bearing for it. But it is a nice idea

 

Well I finished my mod. I bought a diff from a '94 S350 with ASD, no ASR, and 2.82 gears. I swapped the output flanges and the cover from the 400E diff to the new diff. I drove it for about 30 miles on the highway. There is a slight whine in the rear, and I mean slight. I was surprised that this thing did not howl. Here's why, the output flanges support the carrier. When I swapped them over from one diff to the other, I thought that there's no way in hell this thing is going to be close. I thought the rear would have to be set up again. But it is not bad at all. I'll give some more impressions once I get to drive it around some.

I am trying to determine how to correct my speedo. I guess there are correction boxes that can be place between the sender and the gauge? But I was thinking I should just get the right toner ring for the speedo sender on the tranny. Any thoughts.

Thanks to those that provided info for this mod, especially AMGDave.

 

D'oh! It took me a while to figure out what you meant, but I think now I understand. You unbolted the entire side of the housing, and swapped the entire thing over, right? That could mess with the gear setup slightly (backlash & bearing preload). Hopefully you kept the shims from the 2.82 diff and didn't swap those from your original diff, in which case it should be pretty close. I would have tried to swap the flanges (axle stub) alone, but I'm not sure if that's possible - the 210mm ASD setup is different design than the smaller 185mm diff. I'm not certain if you can use the ASD side housing with non-ASD flanges (on the 185mm, you just un-bolt the hydraulics and use a different seal). Shame that I tossed the S350 ASD housing that I had, never thought to look at that more closely, ooops. Well, at least it's working so far - sorry about the snafu there! :o




You need an electronic converter. There is an inductive sender at the tranny which is not adjustable. You can wire it up behind the instrument cluster so the speedometer receives the modified signal. Verify the adjustment via a hand-held GPS to make sure it's accurate, you should be able to get it within 1% of actual. One of the two units below should work fine:

Dakota Digital: http://tinyurl.com/78hvf
Yellow Box: http://yellr.com/

 

Yeah, so the axle stub and side housing had to be swapped. Otherwise, the axles would have to be shortened. The ASD side housing is integral with the ASD cylinders, at least as far as I can tell. If by shims, you mean the metal things that I thought were gaskets on the side housing, I kept them, but I did not put the ones originally on the 2.82 back on the 2.82. The set up is relatively quiet, but I did not run a pattern on the gears to inspect. I did think there was anything I could have done to change it if it was wrong. Even if those are spacer shims, the side housing would have to be dead nuts machined to work with the housing. I guess I'll drive it and see if I blow it up.

Thanks for the links for the speedo correction. I'm on that now.

 

It was 2-3 years ago when I disassembled the W140 ASD diff. I can't remember if the ASD hydraulic cylinders could be removed from the side housing or not (they are separate, bolted on, for the 185mm diff). And even if they do come apart, that would only help if the non-ASD axle stub would plug in, along with the non-ASD seal. Sure wish I had kept that stuff, but I was short on space and it all went in the trash, d'oh.

Yes, the metal things which sort of seem like gaskets, are actually precision spacers. They are available in thicknesses from 0.90-2.60mm. You change the spacer thickness (i.e., add 0.10 to left and remove 0.10 from right) to adjust the backlash, it moves the ring gear closer or farther from the pinion gear. Same idea for bearing preload, but you add or remove the same amount from both sides (i.e., add 0.10 to both sides to reduce preload, or remove 0.10 from both sides to increase preload).

Hopefully the shims on both diffs were of similar thickness, in which case it should work out ok. If you ever have it back out of the car, it wouldn't hurt to check the pattern on the gears, for grins...

 

Couldn't I replace the trigger ring in the transmission? Or if they are all the same number of triggers like with the ABS, couldn't I replace my speedo with a speedo from a W140 with the 2.82 gears? I'll use the box if I must, but I would think there would be a more OEM fix.

 

No, the transmission sensors / rings / etc are the same on all the cars. It's the speedometer heads that are different. The factory solution would be to calibrate the speedometer head for the gear ratio & tires used. Since there was no factory 124 with electornic speedo, 2.82 gears, and 195/65/15 tires... you have to figure out something aftermarket. Another option would be to have your existing speedometer head modified by a VDO shop, this is fairly straightforward, and would probably be in the $100-$125 range. I have a reference to a shop capable of this modification if you prefer this route.

The W140 speedometer isn't the same, AFAIK... don't think it will work in a 124 cluster. It would have the same problem as a 500E speedo, although it's calibrated for 2.82 gears, the W140 (and 500E) use larger tires, so it would still be 3-4% off.

 

Hey Dave,

I think I would like to explore this route if you wouldn't mind passing along the info. Thanks once again. BTW, what should my next upgrade be? Maybe I should start a new thread for that.