[Kennyk82]

I converted my w116 to a Weber carb a few months back, been running great but idle rpm when engine is hot is still too high, however I did get my ac to work which helped lower my idle RPM to about 1000.... but I’ve been driving it more lately and noticed it goes into 2nd gear hard, and 3rd.... but I’ve not felt it shift into 4th gear... my RPMs at 55-60 mph are about 3000.... is that expected or normal for the M110 on a 280s?

 

[Nabstud]

First gear is only used if you floor the accelerated pedal from standstill or you select L gear. 3000rpm at 100 sounds about right. These were known to have firm-ish gear shifts, if they flare when changing that is it good. When was the trans fluid last changed?

 

[Dikdaan]

Yes the 1-2 shift, or in this case 2-3 shift (4 speed starts in 2nd as per first response) is quite firm by comparison to other brands. Mercedes was known for firmer shifting which is by design and helps prolong the life of the transmission, if you have slushy shifts like US cars of same era then the trans will wear out sooner, they were not designed to shift like US cars, firm is good