1978 W116 MPH/RPM Transmission Question
 

Hello,
I am a MB newby. I recently bought a 1978 280SE automatic. When taking off it starts out in gear and switches at about 15mph or so and then again I think about 30-40mph. When doing 40mph the tach reads 2500 RPM. When going 50mph it reads 3000 RPM. When going 60mph it reads 3500 RPM. I have read some things that say the transmission could be designed to start in 2nd thus it does go through four gears. Do these mph to RPM ratios sound normal or I am possibly not shifting into 4th. Any help would be appreciated. Thanks!!!


Kevin

In D the transmission starts in 2nd gear and ends in 4th. In S (slope) it does the same, but ends in 3rd - also shifts into 3rd from a higher RPM than in D. In L it only reaches 2nd gear from 1st. This is such a low 1st gear that the car can climb a wall. What you are seeing is normal. In 4th gear (D), ie: you should see more or less 4000 RPM at 80 MPH. This transmission can be up-shifted manually, which is very helpful for eliminating sluggish starts during in town driving.

Thanks so much

Are you sure it has a 4-speed? My US spec ‘78 450SEL had a 3-speed.

Does the shift gate PRND2L or PRND32?

Sixto
98 E320s sedan and wagon
02 C320 wagon

sixman: You are correct about the V8 engined car; the 1st gear was permanently disabled, leaving only 2nd, 3rd, and 4th.
The 6-cylinder 280, however, does have 1st available, although it normally starts in 2nd.

On what you guys call the "Euro" speedometers there are marks on the speedometer showing where each gear should be engaged - it also shows where you shouldn't be trying to select a lower gear when going too fast. There's only a hydro-mechanical lock out for reverse which if I remember correctly is something like 15km/h (i.e. under this speed you can select reverse whilst rolling forwards if you are an impatient pillock!) - you can in principle select lower forward gears at the wrong moment - hence the marks on the speedometer...

...I'm not sure if the US mph speedometer faces have these marks however as I've only ever driven what I call "original" "Euro" specification vehicles!

Thanks to all for the input.