W123 limited slip Diff - Page 3 - PeachParts Mercedes-Benz Forum

bmwpowere36m3 · #31 02-01-2011, 07:03 AM

I wondering what my options are... currently I have a 2.47 diff installed in my 300CD (turbo). I'm not sure where it came from (W126 or R107) but it’s an open diff with a 210mm ring gear. We had to swap the diff cover from the original diff for it to bolt into place.

Right now I feel like the ratio is a little too low. While on the highway the revs are low... the motor seems to be lugging a little. In 1st, 2nd and 3rd gear the car moves decently, in 4th it really struggles to gain speed till you get to about 3k RPM. Also my speedo is pretty off now.

I'd like to keep this larger diff as I have a 560SL diff (2.47 LSD) that I'd like to use. However what are my options in terms of diff ratios that I could use in this diff?

vstech · #32 02-01-2011, 09:31 AM

make sure your fuel filters and fuel pressures are good before you condemn your 2.47. also verify you have adjusted your valves, and the turbo is operating properly.

bmwpowere36m3 · #33 02-01-2011, 10:03 AM

Quote:

Originally Posted by vstech

make sure your fuel filters and fuel pressures are good before you condemn your 2.47. also verify you have adjusted your valves, and the turbo is operating properly.

That was all done when I got the car... other than verify fuel pressure (but I stretched the spring according to the FSM). The car originally was N/A with a 3.47 IIRC...

t walgamuth · #34 02-01-2011, 10:08 AM

Quote:

Originally Posted by mbdoc

In 1995, I was auto crossing a 1981 euro 280E & decided to make my differential a LSD!
I found out that no one ever offered that for the W123.

So I started measuring MB differentials & found that MANY MB's used a 185MM ring & pinion.

I bought a 16V differential from a junk yard & removed the carrier.
To mount the ring gear you need flywheel bolts & a 5MM spacer & bingo I had a W123 with limited slip.

About 3 years ago Tom W. contacted me & I explained just how to do that job.

So if you can find a used 16V differential, you are 1/2 way there.

Exactly. without your help we would not have begun to figure out what was needed to do.

OM616 · #35 04-20-2011, 10:54 PM

Does anyone know if the splined axel flanges from a late model W126 (the things that stay in the diff that the CV bolts to), will work in a W123 diff?

I want to put a 3.69 ratio in a late model SD and I have a 240D diff. I have read that the large and small housings are the same width at the flanges, but have not confirmed personally.

I know I would have to fab up an adaptor to mount the pig, and I am hoping that I can pull the flanges out of the SD pig and put them in the 240D one so I wont have to mess with the axles.

vstech · #36 04-20-2011, 11:04 PM

same.

t walgamuth · #37 04-21-2011, 04:52 AM

Do you mean the 240 pig will bolt into his SD?

If that is the case, I will sell my 369 diff for $850. It has new friction discs and is ready to go.

OM616 · #38 04-21-2011, 12:25 PM

[QUOTE=t walgamuth;2704159]Do you mean the 240 pig will bolt into his SD? QUOTE]

It is a late model, (91), 126 with the larger housing, so I doubt very much that is will bolt up directly, but do not know for sure yet.

My specific question was regarding the CV flanges and whether they would fit into the 123 diff. I will have to fab up some new mounts to mount the 123 dif to the 126 chassis.

I know I am getting greedy here, but...., What about flex disk flange on the pinion shaft? Is there any chance they share the same spline and are interchangeable? I would bet that the larger housing diff would have a larger pinion spline, but I can hope.

As a note, I am figuring out how complex this project would be and how much to would cost to do, before I commit to it. I greatly appreciate everyone’s help.

lutzTD · #39 04-21-2011, 12:41 PM

[QUOTE=OM616;2704335]

Quote:

Originally Posted by t walgamuth

Do you mean the 240 pig will bolt into his SD? QUOTE]

It is a late model, (91), 126 with the larger housing, so I doubt very much that is will bolt up directly, but do not know for sure yet.

My specific question was regarding the CV flanges and whether they would fit into the 123 diff. I will have to fab up some new mounts to mount the 123 dif to the 126 chassis.

I know I am getting greedy here, but...., What about flex disk flange on the pinion shaft? Is there any chance they share the same spline and are interchangeable? I would bet that the larger housing diff would have a larger pinion spline, but I can hope.

As a note, I am figuring out how complex this project would be and how much to would cost to do, before I commit to it. I greatly appreciate everyone’s help.

late model 126 diff wont work in the w123, but I put an early model 126 diff in my w123 coupe. splines are the same. actually I used the flange from the back of an old auto trans on my 2.47 diff conversion. The W123 axles worked but rubbed a little on the bolts on the side of the diff.

vstech · #40 04-21-2011, 02:35 PM

I answered his question. The splines are same. & he's putting a 123 different in the 126

lupin..the..3rd · #41 04-21-2011, 04:41 PM

Quote:

Originally Posted by Hit Man X

I have a TrueTrac in my F350, works great... and a very similar unit in my Z71 the Torsen diff. Love 'em, nothing to wear like clutch style units.

I'm not a fan of torsen diffs. The only provide lockup on acceleration. On deceleration (braking), they provide nothing, same as an open diff.

Lockup on decel is important in truck for occasions like panic stop while towing on slippery road, or even just engine braking while coasting down a steep hill. You only get lockup on decel with a clutch-pack LSD.

t walgamuth · #42 04-21-2011, 05:17 PM

Quote:

Originally Posted by lupin..the..3rd

I'm not a fan of torsen diffs. The only provide lockup on acceleration. On deceleration (braking), they provide nothing, same as an open diff.

Lockup on decel is important in truck for occasions like panic stop while towing on slippery road, or even just engine braking while coasting down a steep hill. You only get lockup on decel with a clutch-pack LSD.

So you can get a Torsen for a truck?

bmwpowere36m3 · #43 06-22-2011, 07:17 AM

For simplicity sake is it possible to swap over a 3.07 (just) ring and pinion gear set from a W124 300E diff into my W123 diff (currently 3.46). Both are 185 mm, I'm just not sure on the spacing on the carrier. P/N's are the same except the begining 123xxxxxxx vs. 124xxxxxxx.

mbdoc · #44 06-22-2011, 08:27 AM

no, different pinion bearing sizes..

Just find a W123 turbo diff..

eurotuning · #45 01-17-2012, 01:53 PM

Can you help me with instructions or pictures, i have the differential, thanks.

Adolfo

Quote:

Originally Posted by mbdoc

In 1995, I was auto crossing a 1981 euro 280E & decided to make my differential a LSD!
I found out that no one ever offered that for the W123.

So I started measuring MB differentials & found that MANY MB's used a 185MM ring & pinion.

I bought a 16V differential from a junk yard & removed the carrier.
To mount the ring gear you need flywheel bolts & a 5MM spacer & bingo I had a W123 with limited slip.

About 3 years ago Tom W. contacted me & I explained just how to do that job.

So if you can find a used 16V differential, you are 1/2 way there.