Posi diff

[cummins]

I have an 86 300E and was wondering where i could get a posi rear diff for it? Is there a certain model that had it already or any aftermarket parts that anyone has tried and had success with?

[Roncallo]

Originally Posted by cummins

I have an 86 300E and was wondering where i could get a posi rear diff for it? Is there a certain model that had it already or any aftermarket parts that anyone has tried and had success with?

The SL's all had them that year, but I cant say if they are a bolt in.

John Roncallo

[t walgamuth]

I suspect starting in '85 the limited slip diff is the bigger housing.

Tom W

[didlyw124]

I am also interested but I need to know if it can handle alot of punishment as well. I have heard that the 400E has a lsd but couldn't say if it would actually fit but, would the hole subframe swap over is a good question if the diff doesn't bolt in maybe the subframe with the bigger brakes

[t walgamuth]

That would probably work, but will also bring along a much taller rear end ratio. Are you swapping the motor for a v8 too?

Tom W

[cummins]

I'll have engine power. I just need a rear diff that is a posi or LSD that can handle some aggressive driving and something that will fit under my 300E

[300EVIL]

Tons of info here on this subject. Do a search.

Here is a thread with some answers.
Is there an LSD available for a 1986 300E?

Check out this spreadsheet made by gsxr.....


Enjoy!

[didlyw124]

so the mercedes diffs are viscus limitted slip? I had that in one of the 240's that I drifted and it wore out pretty quick, I started to make a diff cooler for it then got rid of the car before I finished it

[t walgamuth]

the 124 126 and 190 and earlier lsd s from mb are friction clutch devices. I think all are set up with 25% slip.

Tom W

[gsxr]

Copy & paste from another thread where I answered similar questions:

You can build a LSD for a 124, but it's not necessarily easy or cheap, depending on the exact year & model of car you have. Anyway, to clear up some misconceptions:


1) The factory ASD system is a normal clutch-type limited-slip diff, PLUS an extra hydraulic function that activates to provide 100% lock when wheelspin is detected under 19mph. Above 19mph, it's a plain LSD, with approx 35% lock from the clutch pack.

2) Yes, the 190E-16 diff is a normal limited-slip (not ASD, no hydraulics). However it's a 3.27 gear ratio (w/ 185mm gears), which is crazy low for a 124. You could swap this in to a 124, but would need a matching speedo from a 124 with 3.27 gears.

3) The 4Matics have the ASD setup in the rear (LSD plus hydraulics). Yes this can swap over to a standard 124, but without the hydraulic lock function.

4) The limited-slip differential (the carrier, i.e. the part with the clutch pack, that the ring gear bolts to) is different depending on the gear ratio. So you can't take the LSD from a 190E-16 (which has 3.27 gears) and put it into a normal 124 diff with 2.65 or 2.87 gears, the spacing is different, the backlash will never be within spec. You MUST use an LSD unit that matches the proper gearset. The LSD unit from the 3.27 gears also works for 3.07, but only those two ratios.

5) You can buy a brand-new LSD unit from the Mercedes dealer (about $1150 wholesale) and pay a rear-end shop to install it for you. Not cheap, but it's new stuff, with new clutches. If you get a used unit from the salvage yard, it will need several hundred $$$'s worth of rebuilding.

6) Remember that all 124's have 185mm diffs, except the M104 and M119 engined models... those have 210mm diffs. The LSD unit for the 210mm diff is actually cheaper, about $800 wholesale, for the E320/500E/E500 with 2.65 or 2.82 gears.

7) Yes, I know what I'm talking about. No, I'm not insane. I built a limited-slip diff for my 1987 300D last year, keeping the stock 2.65 gears. It works GREAT.


An Excel spreadsheet (in PDF form) with details on the various years, models, ratios, part numbers, etc is posted on my website at this link.

Photos of my LSD rebuild & installation are at this link.


Final note: The 400E/500E did not have limited-slip, not anywhere in the world. They had ASR, which simulates LSD electronically by reducing throttle and applying the brakes to the spinning wheel. All ASR cars have open differentials. You can convert them to add LSD (so you have both LSD *and* ASR), which I'm working on for my E500.