Limited Slip Differential - What are my options?

[colombian_gringo]

'94 E420 with stock 2.24 rear differential, no ASR. I'm looking for either a 2.65 or 2.82 ratio.

I've read through the threads on the various forums about swapping in another differential from a W140 or R129. It seems cost prohibitive to buy a new differential (if they're even still available) and it's a crap shoot on how much life is left in the clutch packs on a used differential.

I'm wondering if there are any other options from Quaife, Wavetrac or any other company for this application?

 

[samiam44]

wavetech- get Jono to build you a diff. A used 2.65 from a 1990-1991 SL V8 or a 2.82 from a 420SEL.

Can convert a 350SDL over I believe it has the clutches.. not sure what the cost. Honestly, I would throw a 2.65 in it and be done- cheap cheap cheap. $200< to your door.

M

 

[gerryvz]

I do not believe the standard E500E diff was limited slip from the factory.

I don't know if Jono still has stock on the WaveTracs ... I know last fall he had a few in stock from the group buy, but you know how those things sold....

Jackasic may also be a source if Jono is sold out. Jack-Man just better not sell the one sitting in his Batcave that's MINE ....

Quaife is a much more expensive route to go, hence the WaveTrac group buy.

I think it is possible to slip in some shorter gears though. THere's a few options for doing that.

 

[gsxr]

'94 E420 with stock 2.24 rear differential, no ASR. I'm looking for either a 2.65 or 2.82 ratio.

I've read through the threads on the various forums about swapping in another differential from a W140 or R129.

You need a donor from a 129.066 (2.65 ratio) or 140.04x (2.82 ratio) WITHOUT ASR. The R129 is bolt-in, the W140 requires swapping around more parts and is more work. Save yourself the hassle and get the 2.65 non-ASR diff. There is no factory complete LSD (housing/gears/flanges) for this application and if there was, it would cost more than your car is worth. You need to build one.

I'm wondering if there are any other options from Quaife, Wavetrac or any other company for this application?

Yes, both Quaife (QDF5V) and WaveTrac have LSD's (actually, ATB's, a Gleason-Torsen type) and either of these are highly recommended. There is a factory clutch-type LSD but the price shot up last year ($1500 list) and now it costs more than Quaife / WaveTrac, which are ~$1400. Also, the Quaife / WaveTrac have no clutches to wear out, and both have lifetime warranties.

 

[jhodg5ck]

IIRC, I have a non-asr 2.65 here @ the shop...and I still have one wavetrac sitting on the shelf..;-)

Jono

 

[gsxr]

Sounds like "problem solved" to me! Have Jono build it, then you can swap out the diff assembly yourself. Takes a few hours in your garage. Or drive down to Hotlanta and have Jono sweat instead, while you watch.

 

[jhodg5ck]

I never sweat....

 

[Klink]

I never sweat....

:Jono:

Actually, I think that ancient gianormous fan you've got simply dries it off before anyone can see it!

 

[jhodg5ck]

My OSHA fan?? Best $75 I ever spent!!

 

[Klink]

My OSHA fan?? Best $75 I ever spent!!

LOL, Occupationally Seriously Hazardous Appliance?

 

[jhodg5ck]

Its just a little piece of Darwin we keep on hand..!

 

[colombian_gringo]

Thanks for the info guys. Jono, you have PM.

 

[gsxr]

Don't forget the speedometer conversion box required for the ratio change... I use this one, it has to be the 2-wire "inductive coil" type:

http://yellr.com/ordering.htm

 

[gerryvz]

There are several digital conversion boxes out there. Given that the E500E uses an electronic and not an analog signal, it's important to get the right type of box. And many of them have both two- and three-wire settings. Make sure it's set to the two-wire setting. Ask me how I know....

I've used a speedo signal conversion box in my 560SEC since early 2006 with absolutely no issue.

 

[Hollybrook]

There can be one advantage of a clutch-type limited slip over a gear-type limited slip. Suddenly removing torque and then re-applying it can generate high shock loading of the axles with a gear-type limited slip, which can lead to failure. For the average driver on the street, this will almost never happen, but in certain circumstances, it can be significant.

At our home racetrack, to keep drivers from getting into the deep gravel traps, the owners installed "gator teeth." These were triangular cuts into a concrete pad that got wider and deeper as you got further from the edge of the track. Well, the fast line was to use this surface right up to the edge of the gravel, especially on the turn preceding the main straight. It was worth at least a 1/10th of a second (about 20 feet per lap!), and you HAD to use it to be competitive. This was very rough on the suspension and drivetrain. I had been running a welded diff to save money and had friends with Quaifes, and all of us were breaking stub axles quite regularly. Luckily on our cars, the predominant failure was the weld between the flange and the axle, with the flange spinning on the axle and the wheel staying on the car. After thinking about this, I decided to start running Nissan's clutch pack limited slip, and never had another axle failure. Of course, it didn't hurt that Nismo was sponsoring us and I got a discount on the limited slip.

I suspect the MB axles are sturdier and most racetracks put in curbing rather than gator teeth, so even Jono should be OK with a gear-type limited slip. It is not really intuitive that gear-type limited slips might have such a problem, but you actually lose all drive force when one wheel is not in contact with the ground! Repetitively and instantaneously removing and reapplying full power to the wheels can be quite destructive...

 

[colombian_gringo]

Well it looks like a used differential might be the way to go. A new 2.65/Wavetrac would be cost prohibitive as the price is just about what I paid for my E420. I just can't justify spending that on a diff.

I saw someone on one of the other forums was selling a bolt-in S350 or 300SD setup that they were using in their 400E.

The only question is how much life would be left in those clutch packs.

Does anyone know what the cost would be (parts/labor) to replace the clutch packs? I assume it would involve a full rebuild of the differential to do so.

 

[jhodg5ck]

Anything around 100K and the clutch packs are typically Toast IME.

As I remember, last time Dave built a clutch LSD the parts were pricey.

jono

 

[gsxr]

A used clutch-type diff is a major gamble, and the cost to refresh the clutch pack makes it a poor investment, IMO. I did it once years ago building my first 500E LSD, before I discovered the Quaife would fit. The parts to refresh the factory LSD were only ~$200 at that time, plus many hours labor, and I'd never do it again. Looks like today it would be nearly $500 in parts to refresh a used diff now, plus the cost of the diff, plus labor. And as Jono said, you only get so many miles out of the clutch packs before they need replacement. Suddenly the WaveTrac or Quaife starts to look reasonable. RENNtech charged $4350 for what you want, btw...

 

[colombian_gringo]

The used diff I'm considering is $500 shipped. Figure another $1K to rebuild it and it should be good for another 100K miles, no?
$1500 is much easier to tolerate on a car I spent $2800 to purchase than $2600 is.

If this were going in a 500E then I'd have no problem with it. Dropping around 10-15% of the car's value on a differential isn't bad.
On a 400E/E420 the price of the differential is more like 75-90% of the car's value. Doesn't make sense.

 

[gsxr]

Keep in mind that you can remove the LSD before re-selling the car. At least that's what I would do... swap the stock diff back in when you're ready to re-sell. I'd do that either way though.