The front seats have different part numbers.
The engines have different connectors for some instruments.
Different transmission numbers, but should bolt up.
Some of the diffs are interchangeable, see attachment.
Different brake boosters.

That's all I looked up.

Depends on how much you want to remove and store for future sale or use.

Good luck and keep us posted.

Attached Thumbnails

 

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83 SD

84 CD

Front seats are still swappable. The difference is that W126 seats are power whereas W123 seats are manual... I am swapping W123 seats into my W126 because the old power seats were moody. They swap fine.

The only differences between the two engines are the oil filter housing (the W126 has an electric oil pressure gauge where the W123 has a manual one), and the engine mount arms.

The trannies have different part #s because the W123 uses a mechanical speedo whereas the W126 has an electric one. The speedometer drive/feed is located in the tail end of the transmission. The tail from a W126 transmission (722.303) can be swapped onto a W123 transmission (722.315), but a W123 transmission tail cannot be swapped onto a W126 transmission because the mechanical speedometer in the W123 requires a little oil feed line coming from the main body of the transmission that the W126 does not have.

The 3.07 is interchangeable because it is a 1.1 L casing... other casings, such as the 2.47 and 2.24, are not swappable because they are 1.3 L casings. Also, all W126 differentials made after 1985 are not swappable.

Brake boosters are different, but swappable. The W123 booster is a bit smaller, so I don't know how that affects things.

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"Senior Luna, your sense of humor is still loco... but we love it, anyway." -rickymay ____ "Your sense of humor is still loco... " -MBeige ____ "Señor Luna, your sense of humor is quite järjetön" -Delibes

1982 300SD -- 211k, Texas car, tranny issues ____ 1979 240D 4-speed 234k -- turbo and tuned IP, third world taxi hot rod

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