All, as the subject says? I have a bearing noise in 1st gear and am wondering if the W123 230D trans is a suitable swap.

Thanks

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With best regards

Al

Iron case, or aluminum case?

Good question, one is a 77 (D) the other is an 80 (G).

__________________
With best regards

Al

I believe that the flange for all the diesels and 6 cylinders from the mid 60’s to 1985 are the same. So I believe you could bolt the transmission on, but the gear ratios are likely different for 1st, 2nd and 3rd.

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Past mb: '73 450sl, '81 280slc stick, '71 250, '72 250c, '70 250c, '79 280sl, '73 450sl, parted: '75 240d stick, '69 280s, '73 450slc, '72 450sl,

If the '77 240D trans is the donor, then it is a bolt-up to the engine. If it is replacing an aluminum case box then the shift linkage from the '77 will need to be used also. The cross-member & mount from the '77 may be required. Driveshaft length should be the same.
The internal ratios are close enough that the differences will not be felt.