Is my transmission working properly?

[Rbatt]

1967 230SL auto

I imported my car from the US last year. I sent my car straight to the bodyshop for new floors to be welded in and it arrived back home on Friday!

This is the first time that I have driven the car. The engine is smooth and pulls strongly. However, The gearbox is slow to upshift despite having had a recent fluid and filter change. Is this normal for an auto gearbox of this age? It seems to shift from 3-4 around 3500 rpm, which is much higher than a modern auto box.

It would be really helpful to know what to expect from this gearbox so that I can work out if the existing shift patterns are normal or whether I need to have it seen to.

Thanks

[WRe]

Hi,
the workshop manual describes a test how the automatic gearbox should operate. Attached the German version. You should seize the opportunity to learn German or use an Internet translator.
...WRe

[Rbatt]

Thank you for this. I've put it through a translating program, and it looks like the gears change at set speeds (mph/kph) rather than at set engine speeds (rpm). Is this correct? My transmission won't change from 3-4 until around 3,500 rpm, whereas nowadays we're used to the 'box changing up at much lower rpms. Maybe this is normal for an early automatic and I just need to get used to it?

[WRe]

Hi,
if you drive "normal" (4/D) the gearbox operates as follows: at 25 km/h from 2. to 3. and at 40 km/h from 3. to 4.
If you drive with kick-down as follows: at 58 km/h from 2. to 3. and at 120 km/h from 3. to 4.
You can find the corresponding engine revs in attached file according to your rear axle ratio.
...WRe

[ja17]

First thing to do, remove the access panel on the tunnel (right side). View the transmission linkage rod to make sure it is not stuck from inactivity. 

[Rbatt]

This will be a job for the weekend. Is it easy enough to do?

[Rbatt]

First thing to do, remove the access panel on the tunnel (right side). View the transmission linkage rod to make sure it is not stuck from inactivity.

What would the symptoms of a sticking linkage rod?

[Benz Dr.]

No kick down and clunking when down shifting from 3rd to 2nd as you coast to a stop.

[Rbatt]

I've finally had an opportunity to have a closer look at this issue. The gearbox will kickdown, so I'm wondering if it's still a good idea to look at the linkage under the inspection chamber on the rhs of the transmission tunnel? I'm asking because I have recently had new carpets fitted and I'd prefer not to have to pull up the newly glued carpets! But I will if you think it's worth the trouble?

I did notice that the gearbox had been overfilled with fluid (about 1cm on the dipstick). I drained some off and added some Lucas auto transmission additive. It's now at the correct level.

It's too early to tell if this has made much of an improvement as I'm wishing that it has and the "placebo effect" can be misleading.

[perry113]

I know that the accelerator linkage and throttle linkage has to all be spot on for the transmission to shift properly. There must be no slack whatsoever in the system meaning that as soon as you touch the gas pedal the air intake throttle plate and injection pump arm move together.
I ran into this many moons ago when I first got my 230SL back on the road and found the transmission slipping and shifting poorly. Once I went through and did a 101 on fully adjusting the linkage properly then the transmission shift perfectly.
I hope this may help in your evaluation.
Regards
Peter

[Madusudo]

Greetings from a new 1970 280SL owner.  It has 94.000 miles and I have been told it has not been driven much in the last few years.

This has been a very informative topic for me as the first time I drove my 280SL, it was shifting 3rd to 4th back and fourth for about three to four times.  I was then told that it is normal when the transmission has not warmed up yet.  It shifts normally as I drove a few minutes longer.  Is this correct or should i have it checked at the local MB shop?

I am relieved to know that the 1st gear does not get into any action unless you floor the gas pedal as I was really wondering why the car seems to only shift three gears under normal driving (2-3-4 only).  It does however feel as if the gear ratios vary greatly as you feel a kick in the butt when it upshifts to the next gear.  However I believe the shifting does not really happen at same speed as mentioned above.

Please let me know what I should do if this does not sound like a properly working automatic transmission.

Thank you!

[Benz Dr.]

I've finally had an opportunity to have a closer look at this issue. The gearbox will kick down, so I'm wondering if it's still a good idea to look at the linkage under the inspection chamber on the rhs of the transmission tunnel? I'm asking because I have recently had new carpets fitted and I'd prefer not to have to pull up the newly glued carpets! But I will if you think it's worth the trouble?

I did notice that the gearbox had been overfilled with fluid (about 1 cm on the dipstick). I drained some off and added some Lucas auto transmission additive. It's now at the correct level.

It's too early to tell if this has made much of an improvement as I'm wishing that it has and the "placebo effect" can be misleading.

You should never glue your tunnel carpet in place. If you need to work on something you will find out why rather quickly.  I would check o see if you have wide open throttle ( WOT ) when you have your gas pedal at kick down position. This can be adjusted at the cross shaft on your firewall.
The difference between full and add on the dip stick is only 300 ml so it's easy to over fill. Level should be checked while in park after the engine is hot.

[Cees Klumper]

Greetings from a new 1970 280SL owner.  It has 94.000 miles and I have been told it has not been driven much in the last few years.

This has been a very informative topic for me as the first time I drove my 280SL, it was shifting 3rd to 4th back and fourth for about three to four times.  I was then told that it is normal when the transmission has not warmed up yet.  It shifts normally as I drove a few minutes longer.  Is this correct or should i have it checked at the local MB shop?

I am relieved to know that the 1st gear does not get into any action unless you floor the gas pedal as I was really wondering why the car seems to only shift three gears under normal driving (2-3-4 only).  It does however feel as if the gear ratios vary greatly as you feel a kick in the butt when it upshifts to the next gear.  However I believe the shifting does not really happen at same speed as mentioned above.

Please let me know what I should do if this does not sound like a properly working automatic transmission.

Thank you!

The behavior of your transmission does not sound normal, it should not shift up and down between 3 and 4 when cold nor jerk when upshifting. Best do the basic checks (fluid level, linkage rod) and take it from there.

[Madusudo]

Thank you Cees.  Yes it was shifting 3-4-3-4-3-4 in two seconds.  But that was gone after I drove the car longer. I will definitely have it checked when I am back from this trip.

The transmission behaves very different from the 300SEL.  I am wondering if the difference is because the SL has a "sporty" transmission. But you are correct, it should not jerk like it did.