350/450SL Kickdown

[DieselPaul]

So last night I drove my 350SL down to Lancaster for a family function, lots of back roads, did a great job of reminding me how much I like this car.

However, my car upshifts pretty fast, it'll hit 3rd before 40mph and one it is is there, it doesn't seem to want to come out of third until you slow down. To have any really fun you have to manually shift into second.

Last night I was going up a hill about 35-40mph and I matted it, it didn't even consider downshifting, it didn't sputter or lug, it just dug itself out so to speak and eventually sped up the hill. On one hand I was impressed by the torque of a motor with this many miles, but on the other hand it definitely should have shifted down.

What should I look at in terms of shift points?

I see the there is a linkage rod that goes from the throttle down to the trans like on my W124. Is there a how to on adjusting this style of shift rod?

Thanks!

[rowdie]

The kick down switch is under the accelerator pedal. There is a solenoid on the side of the trans. with one wire connected. The rod you describe connects to the control pressure lever. There is a bushing where the rod connects to the lever and it disintegrates. The rod is adjustable where it attaches to the throttle linkage but check the bushing first.
'73 450SL.

[Graham]

Section 07.4-300 in M116/7 engine manual describes how to adjust the transmission Control pressure rod. Once you have other parts of linkage properly adjusted, you push back on control rod so that it pushes lever on transmission all the way back. At that point, you adjust the ball socket head on the pressure rod so that it just drops onto ball on the throttle mechanism. Best to read the manual

As Rowdie said, make sure the bushing on the transmission lever (under car) is intact and not worn.

You can check the kick down switch with a meter attached to wires that attach to solenoid under car on side of transmission (Rowdie has a pic of that ). If meter shows power is getting to solenoid when pedal is floored, then you may have bad solenoid. It is easy to pull and then you can check solenoid coil for continuity on bench. Mine was burned out, but I got a good used one from Sun Valley Dismanters for $50.00.

PS: My kickdown hardly ever actuates. You have to push pedal far down to get it to work. My car stays in top gear most of time unless I change manually.

PPS:

This what the 1972 MB TDM says for shift points for the 107.044 3-speed :

Selector in D

At idle
1 > 2 30km/hr 2 > 1 19km/hr
2 > 3 45km/hr 3 > 2 35km/hr

Full throttle
1 > 2 68km/hr 2 > 1 19km/hr (kickdown 51km/hr)
2 > 3 138km/hr 3 > 2 60km/hr (kickdown 123km/hr)

Selector in S

At idle
1 > 2 34km/hr 2 > 1 23km/hr

Full throttle
1 > 2 77km/hr 2 > 1 27km/hr (kickdown 62km/hr)

PS: Don't know what they mean by "idle" in this context. Could car get to 45km/hr when at idle speed (700-800rpm)?

[DieselPaul]

I will do that today when I head over the to the garage.

I know the Mercedes transmissions love to hang out in top gear, but yesterday I went probably 75% throttle from a stop and it shifted 1-2 and 2-3 at like 2700 rpms. In 1st or 2nd I've never seen the car above 3000 rpms. The shifts are really good, but just very low.

[meltedpanda]

The linkage adjustment worked well for me, I have it as good as I can get it considering some of the bushing are worn. If they are too far gone, fix that first, then adjust

[DieselPaul]

I've been busy with my 190SL and I haven't worked on this car lately, does anyone have the part number for the linkage bushing?

Thanks

[rowdie]

110 277 05 50.

[DieselPaul]

You're the man rowdie, thanks

[cushjbc]

DP,

I have the same issue - have not tackled it yet. Previous posts on this topic lead me to believe that I will have to remove the control pressure lever to install the bushing. The tunnel is tight.

Can you please post your results if you accomplish this installation.

[DieselPaul]

I'm headed to the dealer this afternoon to order the bushing, ill post my results when I tackle it.

[rmasteller]

For the attachment of the linkage at the transmission, you can get the dealership to replace this for you for free. There was a recall/campaign numbered 84-0113 because, as you guys said, this bushing degrades. They replace the plastic or rubber part with a metal part. I'm sure it costs very little and many of you can do it yourself, but I wanted everyone to know just in case someone could use the info.

I had this done because I had the car in the dealership for something else. On my 1980 450SL, the car did not kickdown at all when I first owned it. While looking around the engine bay, I found the rod disconnected from that rotating plate in the throttle linkage assembly. The bushing (socket) that the linkage connects to was missing. I got one from a friend's parts car and now my car has kickdown. But, it won't hold the gear long. It shifts up again at around 3,000 rpm. So, it sounds like I need to work on adjusting that rod and testing that solenoid. Thanks for the tip, guys!

[rowdie]

The recall applies to the connection up on the intake. The bushing at the rod and control pressure lever is not covered.

[rmasteller]

On the intake? I thought this rod went right from the throttle linkage to the transmission. Please elaborate.

[meltedpanda]

I beleive what Rowdie is referring to is that all sits on top of the intake manifold, all those connections eventually end up in concert at the maifold

[rowdie]

Yes throttle linkage which is connected to the intake manifold. I was just stating the lower bushing where the rod connects to the control pressure lever is not the one covered in the recall.