1st Gear giving me grief

[Terqel]

hello all, I have 1981 280SL with the M110 280 motor and a 4 speed auto box which should start off in 1st but starts in 2nd. Unlike the earlier models 1971- to 1978? which start off in 2nd. It will kick down to 1st only. I cannot select it via the gear shift lever. The box has been rebuilt and the valve body tested. The car starts in 2nd and when it changes to 3rd it flairs slightly. 3rd to 4th is very good. Has any body come across this issue?

 

[Tony66_au]

My W124 230TE starts in 2nd, its a form of traction control i believe and there is a mod that allows it to start in 1st gear although its a fairly low gear.

 

[Oversize]

I wasn't aware the 280s had a 4 speed box. From what you describe it currently only has 2 speeds during normal driving, but you can provoke 2nd to 1st through kickdown. What's on the quadrant? 1, 2, 3, D, or 1, 2, D?

 

[Terqel]

280 SL have always had a 4 speed box and started in 2nd to 4th gear during the Iron block 350s and 450s V8 period 1971 to 1978. These early V8s ran a 3 speed box. When MB introduced the 380 and 500 V8s they fitted them all with the 4 speed box including the 280. The change pattern for the 280 and the 380 was 1st to 4th gear with the 500 2nd to 4th more torque I guess. My quadrant is S,L,D,N,R, P. I currently start in 2nd to 3rd to 4th. It used to start in first. Maybe it is something to do with the valve body. I hope this makes sense.

 

[Oversize]

If you only have S, L, D then how can it be possible to manually select 1, 2, 3, 4? To me S means second, L means 1st and D means 3rd. Thus only 3 speeds. But it sounds like you know more about the model options, so I have no clues...

 

[Terqel]

thanks for your input Mark, I think I might have issues with the valve body

 

[Oversize]

It just goes to show how long it's been since I've driven mine. I have the same on my quadrant and only 3 speeds. I hope you find your problem, because starting in second is just wrong. Combined with a heavy accelerator spring, they can feel slow.

 

[kunbarrie]

the old 4 speed tranys take off in 2nd gear light throttle,push pedal to floor it will kick down to 1st,can tighten the kickdown cable to have 1st gear all time but makes gear shift very harsh,later series eg 202 with 722,6 trany have same system but controlled with s/w switch on console.

 

[sean sherry]

My newly aquired S L 280 '81 has 4 speed Auto which starts in 1st at all times. The L locks in 1st gear , the S prevents a 3 to 4 shift and allows 3-4 and 4-3 manual overide shifts as necessary. An Auto box responds to throttle pressure (Your right foot) and govenor pressure (your road speed)
They oppose each other and the greater pressure wins resulting in up shifts or down shifts.The vacumm modulator sets the oil pressure via engine load and the cable from the accelator linkage sets the shift points. Both can effect the shift quality , it's a balance, though the modulator is king of the hill. A quick check of the shift cable and it's valve in the box would be to disconnect it and see if the box now starts in 1st. If so you have honed in on the problem. I set mine up by feel and it drives fine. EXCEPT for a flare on the 3- 4 shift on light throttle ie high vacumm to the modulator. I have a modified spring for the 4 th gear accumulator to cure it . Hopefully ! Sean

 

[sean sherry]

P.S I believe that the 6 cyl. engines with 4 speeds would be set for 1 st gear starts as they don't have the torque of the V8s. Could you have the wrong Transmission or perhaps the valve body ? Sean

 

[Terqel]

thanks Shean, my 280SL should start in 1st and the kick down will select 1st but I can't pull it into via the shift lever? I have slight flaring between 2nd & 3rd
and it changes up and down correctly except it won't start in first. I will get my head around your suggestions and see how it goes.

 

[sean sherry]

Hi Tergel ,Try adjusting the modulator in half a turn on the T piece to fix the 2-3 flare and maybe a full turn in. the other shifts may be a bit firmer but these transmissions will never shift like an American unit Sean