R129, got any driving tips?

[Garista]

I was wondering if MB r129 owners have any tips on driving and using the auto shift and kickdown etc. I am just getting to know it and it would be helpful, for me especially the 300 SL with M103 engine.

Mine seems to need warming up properly before any performance. If I try to accelerate too suddenly in 3rd just after starting it will disengage and then reengage, I think (?), I have to be gentle. It does do the kickdown fine when I need it, once warmed up. Should I always start in 2nd?

 

[Wighty]

I was wondering if MB r129 owners have any tips on driving and using the auto shift and kickdown etc. I am just getting to know it and it would be helpful, for me especially the 300 SL with M103 engine.

Mine seems to need warming up properly before any performance. If I try to accelerate too suddenly in 3rd just after starting it will disengage and then reengage, I think (?), I have to be gentle. It does do the kickdown fine when I need it, once warmed up. Should I always start in 2nd?

Sounds like there might be some fault codes that need reading ?
Do you have a local MB specialist?
What mileage has the car got , when was the gearbox last serviced ?
If it’s a 5g gearbox can you check the atf level ?

 

[LostKiwi]

Shouldn't do that. No codes as it's an early hydraulic gearbox - minimal electronics.
Check fluid level and perhaps change gearbox oil and filter.

Early gearboxes start in second by default and will only use first when manually selected or if floored off the line

Biggest thing to remember is it's not a sports car. It's an elegant boulevard cruiser and open top GT.

 

[Blobcat]

As per above, I’m a big exponent of warming cars (and bikes) up fully before caning them senseless

 

[Garista]

The previous owner (garage) said they had the gearbox reconditioned, it is pretty high mileage (so it was due they said), but it has been very well looked after, so a lot of it seems like new, it was just a bit dusty after being in Spain. Got no bills for it but the transmission oil was nice and clear a few weeks ago, ATF level is correct (I was set to change it).
It will move off in 2 or 3 setting, but not D. Switch to D after moving a bit. After that very smooth and hard to sense any changes in gear.
So I guess it is 2nd by default at start anyway, as you say. I find it quite hard to tell in this car. I don't think anything is wrong, it is just a characteristic, once warmed up it is very happy and I can floor it fine then.

 

[LostKiwi]

There's something not right.

It should move off in D and then change up the gears.
2 should start in second (unless floored when it will start in first then change up to second and no further
3 should start in second (or first if floored) and then change up stopping at third.
D should start in second (unless as previously mentioned) then move up through the box to 4th.
Sounds like yours is only using the gear selected and not behaving as a full auto.

You should hear the gear changes in engine note and see them on the rev counter.

 

[Garista]

There's something not right.

It should move off in D and then change up the gears.
2 should start in second (unless floored when it will start in first then change up to second and no further
3 should start in second (or first if floored) and then change up stopping at third.
D should start in second (unless as previously mentioned) then move up through the box to 4th.
Sounds like yours is only using the gear selected and not behaving as a full auto.

You should hear the gear changes in engine note and see them on the rev counter.

Yes, ok, peculiar.
I think I know what is happening now.

If I start to move off in 3rd, it is definitely in 3rd, and that is too high a gear so it blips the throttle to get to a lower gear and changes it, and I continue. Now, if I start in 2nd, it is fine and then I change to 3rd, and then it is fine and then D, fine, and it all goes pretty damn fast too, and smooth, if in that order.
No, it will not move off in D. It will move off in reverse (have not tried to go to D directly from reverse yet). It seems to want to move off in 2nd.
This all seems to be how it is intended rather than incorrect (?). In fact, now I know what to do it seems good.
The gear changes while driving are very blended in, except the kickdown which dramatically drops the gear.
Once in D it is ok at any speed, or stopped at lights etc.

 

[Garista]

Er, no I am wrong, I think it stays in 3 but de-connects if I push too hard when too slow.
So, it stays in 2 and 3, and is only auto in D.
So like a semi automatic gearbox.
When using these correct it is very fast.

 

[LostKiwi]

No not correct.
With the selector set to D it should start off in second, go to 3rd, then to 4th without you touching the selector.
If it doesn't do that there is a problem..

 

[Garista]

No not correct.
With the selector set to D it should start off in second, go to 3rd, then to 4th without you touching the selector.
If it doesn't do that there is a problem..

In 3rd it stays in 3rd, so if I slow down it is almost like an electric car in that the engine slows it. It is acting like the auto in my ML, which if you tap it to first or second or third it will stay in those gears, while D is auto, except that it will go straight to auto D from start, the SL will not.

It doesn't seem like anything is wrong.

 

[Garista]

Trans: 722363 03 604070.

So, 722.3/4 gearboxes should work like this: in 3 it can change down to 2 or 1, in 2 it can change down to 1, this might be for descending a steep hill to use engine braking. In 3 it will not change up to D. I think my car might be changing down from 3 to 2 etc, I will have to try it out again (i've been driving without thinking much about it until now). Maybe this is what it is doing, changing down when I start off in 3. and it blips the throttle So this is as you said LostKiwi.
But it will not move off in D, only 2 or 3.
As I am repairing things as I go and have re attached some wires, things are changing so I need to test drive more.
I installed the new ignition switch the other day and some things seem different and better.
Could the problem be because the wheel speed sensors aren't working? I have them on order but the light for ABS is on. It might also need new front disks. I tested the sensors and they are not functional.

 

[Garista]

Ok LK, now it is working properly! I did not try it since the new ignition switch. Could this be the difference? So it moves off in D. It has not done this since I bought it. And I can feel the shifts and see the rev counter rev. What a relief! I had got used to it. Thank you.

 

[LostKiwi]

The ignition switch can't affect the gearbox.
The gearbox in a 722.3,/722.4 uses hydraulics to select gears based on engine load, throttle position and road speed. There is no electronics.

As stated previously selecting position 2 will allow 1st or 2nd gear with automatic changes between them
Selecting position 3 allows 1st, 2nd and 3rd gears to be used with automatic changes between them.
Selecting D allows all 4 gears to be used with automatic changes between them.

It should pull away from stationary in all positions D,3,2 and will default to using second gear off the line changing up when required (if the selected range allows.

 

[Garista]

The ignition switch can't affect the gearbox.
The gearbox in a 722.3,/722.4 uses hydraulics to select gears based on engine load, throttle position and road speed. There is no electronics.

As stated previously selecting position 2 will allow 1st or 2nd gear with automatic changes between them
Selecting position 3 allows 1st, 2nd and 3rd gears to be used with automatic changes between them.
Selecting D allows all 4 gears to be used with automatic changes between them.

It should pull away from stationary in all positions D,3,2 and will default to using second gear off the line changing up when required (if the selected range allows.

Thanks, yep, ok not the switch; well it seems to be doing all that correctly. Probably I just didn't understand it. What it seems not to like is moving from P straight to D, then it won't move off, I have to go towards 3 a little bit then back to D and it will move off in D fine. Otherwise all else is as you say I think. It has a different character than when going up manually through the gears to D, which I was used to. I have a crap battery that I need to change, it keeps losing charge. The wiper is now working properly.

 

[LostKiwi]

Sounds like the selector linkage needs adjustment.

 

[Garista]

Sounds like the selector linkage needs adjustment.

I did detach and re-attach the thing that goes to the selector when installing the ignition switch. But presumably you mean something under the lever?

 

[Garista]

I think it is probably driver error. I'm a bit nervous driving it, I've had problems with the ML (idler pulley broke) and this car has got to work at the moment.

 

[LostKiwi]

I did detach and re-attach the thing that goes to the selector when installing the ignition switch. But presumably you mean something under the lever?

Under the car. Steel rod between shifter and gearbox. Adjusts at one end for length.
Probably not correctly adjusted or is worn where it attaches.

 

[Garista]

Under the car. Steel rod between shifter and gearbox. Adjusts at one end for length.
Probably not correctly adjusted or is worn where it attaches.

Ahhh thanks. I will take a look soon, going to change the fuel filter when it arrives so I will do it at the same time.
Hard to get under this car, I will have to buy a couple more jack stands.