Hello,

Is the same speedometer used in the 240D manual trans as in the auto trans?

Thanks.

I'm not certain but if there is any difference it's probably just in the hash marks for the shift points.

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"Rudeness is a weak man's imitation of strength" - Eric Hoffer

I don't think there is a difference from auto to manual. I've attached a screenshot of the EPC, showing which speedometers you can get.

Attached Thumbnails

 

I just swapped my ‘78 manual with an ‘83 auto. It works great, no variation in speed.

I believe there is a small difference in the stick vs auto cars to allow for slippage with the auto. Maybe 2 mph at 60?

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

Does that help or exacerbate the deviation created with larger than OEM profile tires?

the speedo cable comes out of the output shaft so there is no slippage.

the slippage is just in the torque converter impeller and the engine rpm. The turbine in the torque converter and everything behind it has no slippage.

I see you make a good point.

The speed of the car, then is not what is adjusted . It must be the hash marks indicating maximum speed in each gear. In this case the slippage matters to the protection of engine speed. IE if there is slippage, and we know there is, the car will be safe to drive faster downhill before reaching maximum allowed engine speed.

__________________
[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

The speedometer is driven off the tailshaft in the transmission. It doesn't matter if you have automatic or manual, there is no slippage as far as the speedometer and driveshaft is concerned. What does matter is the final drive ratio. If the final drive is the same for auto/manual cars, then you can swap speedo heads with no issue. If the final drive is different, you will have incorrectly reported speed and odometer mileage.

__________________
Current stable:
1995 E320 157K (Nancy)
1983 500SL 125K (SLoL)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

Gone and wanting to forget:
1985 524TD 167K (TotalDumpster™) [Definitely NOT a Benz]

Perhaps if you're driving down a vertical cliff your argument could hold, but otherwise you're going to have the engine pinned to reach top speed (even downhill). The slippage in the torque converter is ~100-200RPM meaning that your top speed is *SLOWER* in an automatic than a manual car for the same engine RPM. In a modern car with a lockup torque converter it's a moot issue since there is no slip at highway speed, these cars do not have a locking T/C.

__________________
Current stable:
1995 E320 157K (Nancy)
1983 500SL 125K (SLoL)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

Gone and wanting to forget:
1985 524TD 167K (TotalDumpster™) [Definitely NOT a Benz]

Well you don't have to be in the top gear to over rev the engine going downhill. It is not I who thought it was needed to have hash marks on the speedo, it was mb.

__________________
[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

When the car is rolling the needle goes clockwise indicating the approximate speed limit as I maintain pace with traffic. When I stop the needle agrees. (no batteries required)
The automatic device on mine must be broken. I still have to use the clutch.

All the transmissions have the same drive ratio. Speedos are different based on the final drive ratio and tire tread diameter.


The hash marks are not shifting points or RPM limits, they are maximum safe speed to downshift.