300 SDL Diff Swap

[Inspect2020]

My differential went out a few years ago and so I parked the 300 SDL. Bought a differential and instrument cluster from a 560 (not sure of the year but it does have the ABS sensor) and am finally getting around to the swap. (Drunk driver totaling my other two cars parked on the street in front of my house renewed my interest in completing this project)

The new 2.47 diff mounts up under the car and to the drive shaft but the axle flanges (not sure what they are called) are larger and do not bolt up to the sub-axles. What is the best way fix this?

[aaa]

Swap the flanges from the old diff? They're probably held in with a c-clip just like the old style axles.

[Inspect2020]

Could not find any c-clips on the outside of the housing or on the flanges.

[DeliveryValve]

The C-clips are found within the spider gear assembly. The original sdl diff is narrower than the sel diff and one member found the axels are longer. So the sel axels would be needed. Also I do believe the sdl axle flanges will not fit on the 2.47 sel diff.


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[ashedd]

put new axle seal's on too... they will start leaking when you swap flanges.

[Inspect2020]

Originally Posted by DeliveryValve

The C-clips are found within the spider gear assembly. The original sdl diff is narrower than the sel diff and one member found the axels are longer. So the sel axels would be needed. Also I do believe the sdl axle flanges will not fit on the 2.47 sel diff.


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Will the SEL axles bolt up on the wheel end? The wheel hub flange kit is the same part number for both SDL and SEL but I think the axle bolts up to an intermediate flange and the tire bolts to the wheel hub flange.

[Brian Carlton]

Originally Posted by DeliveryValve

The C-clips are found within the spider gear assembly. The original sdl diff is narrower than the sel diff and one member found the axels are longer. So the sel axels would be needed. Also I do believe the sdl axle flanges will not fit on the 2.47 sel diff.


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As we are painfully aware, the 2.47 diff is the larger housing and uses the larger flanges with the larger 12mm screws on the flanges.

None of that hardware can be exchanged with the hardware on the 2.88 diff.

The 2.47 needs the axles that came with the diff.

[Brian Carlton]

Originally Posted by Inspect2020

Will the SEL axles bolt up on the wheel end?

The engage into splines on the carrier at the wheel. A long socket head cap screw with a Bellville washer secures the axle in the splines.

All the axles fit the wheel carrier.

[cho]

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recently I had to make just the opposite
I took diff from 91 SDL in mine 87 500sec (2.24 thou...)
I had to take flanges from old diff and put it
in the SDL's, everythig else fits perf.


just my2c

[Brian Carlton]

Originally Posted by cho

.

recently I had to make just the opposite
I took diff from 91 SDL in mine 87 500sec (2.24 thou...)
I had to take flanges from old diff and put it
in the SDL's, everythig else fits perf.


just my2c

I need to be absolutely clear on this:

If the flanges from the 2.24 diff fit the 2.88 diff, this would confirm that the 2.88 diff is the larger housing, with bolt on side flanges, and it also uses the shorter axles and the larger 12mm socket head cap screws at the flange.

My conclusion, above, was that the 2.88 diff was identical to the 3.46 diff and uses the housing without the bolt on side flanges. This housing is quite a bit narrower than the 2.47 diff and it requires the use of longer half shafts. It also uses the smaller 10mm screws on the flange.

Please reconfirm the above and I'll amend my post if I am mistaken about the 2.88 diff. However, the photos by the OP clearly show that his 2.88 diff does not have the side flanges and is of the smaller housing............identical to the 3.46 diff.

[treetrimmer]

Why not just put in a good SDL diff? Sure sounds a lot easier. I might know where there is one, PM me if interested.

[cho]

Originally Posted by Brian Carlton

I need to be absolutely clear on this:

If the flanges from the 2.24 diff fit the 2.88 diff, this would confirm that the 2.88 diff is the larger housing, with bolt on side flanges, and it also uses the shorter axles and the larger 12mm socket head cap screws at the flange.

My conclusion, above, was that the 2.88 diff was identical to the 3.46 diff and uses the housing without the bolt on side flanges. This housing is quite a bit narrower than the 2.47 diff and it requires the use of longer half shafts. It also uses the smaller 10mm screws on the flange.

Please reconfirm the above and I'll amend my post if I am mistaken about the 2.88 diff.

sorry Brian,

but I had no intention to question any of your statement
I just wrote what my mechanic has done and I was watching
him doing it ... the flanges from sdl did not fit to my axles so
he take my old ones and put them in sdl diff.. just replaced
them ... that is what I saw...and I m driving it today

only thing that I had to care about before purchase of the diff
is that it has to be gen2 diff ... on 91 sdl is gen2 and it did fit
on my 500sec .. with voodoo described above




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[cho]

Originally Posted by treetrimmer

Why not just put in a good SDL diff? Sure sounds a lot easier. I might know where there is one, PM me if interested.

only thing that I can think about is noise... which is in his case
(from 2.88 to 2.47)
is reduced and shifts are longer, but no end speed ....


however i would not recommend as the car becomes a kind of
slow dog.....


.

[cho]

Originally Posted by Inspect2020

Bought a differential and instrument cluster from a 560 ...

any chance selling your old one (cluster)?

I have one from 300sd in my coupe but in half-working
state...also 300sd was a 3.07 so no proper calc is done...


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[Brian Carlton]

Originally Posted by cho

.. the flanges from sdl did not fit to my axles so
he take my old ones and put them in sdl diff.. just replaced
them ... that is what I saw...and I m driving it today





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Were the flanges on the SDL smaller than the flanges on the SEC? If so, there is no possibility of swapping those flanges. The diff case is larger..............see the OP situation..........