engine problems, transmission problems

[mgmoore]

Hi,

Iv'e recently imported a very nice 230sl from the states the car was fully serviced by an excellent classic car specialist prior to arrival in the UK. The engine was rebuilt 70k miles ago - compression test done with excellent results and the transmission is newly rebuilt 2017. With that one would assume a problem free car....However, upon arrival to the uk i took the car out for the first time for an hour or so and it performed well, although i did notice that the car hesitated around the 60-70mph mark. Put that down to it's relative lack of use.

The following morning took the car out again. Noticed the car running a bit rough as if intermittently on five cylinders then six -belching out blue smoke upon acceleration. Removed the plugs, wire brushed them up, started the car up smoke now looks more grey/black than blue? Took the car for a brief drive and noticed the auto box was inoperative, jumping through gears. Now i'm thinking there must be a link between the excessive exhaust smoke and the gearbox. A quick flick through the haynes manual on auto boxes and it states
"smoke from exhaust-not due to engine wear - Damaged modulating pressure transmitter diaphragm allowing fluid to enter intake manifold through vacuum line"  However, what about the gear box jumping the gears, is this because some of the fluid has been lost?

Puzzled, advice much appreciated.

Thanks,

Mathew         

[wjsvb ✝︎]

I'm not directly familiar with MB trans modulators, but the problem with your car is exactly what happens with US cars with faulty modulators.  Recommend you start with that!  The tech manual will guide you.  Jon

[ja17]

Yes, it sounds like the modulator diaphragm has failed.  Check the transmission fluid level. Also you will find that #6 spark plug is getting fouled from sucking transmission fluid into the combustion chamber. The fix is not too difficult. No transmission removal required. 

[mgmoore]

Hi,

Thank you very much for the replies. Confirms what i thought. Was wondering for some guidance on how to find the notes for modulator diaphragm removal. Managed to find the picture of the outo box with everything labelled but that's it.

cheers,

Mathew

[Pawel66]

Here you may have a hiint:
https://www.sl113.org/forums/index.php?topic=13766.msg93527#msg93527

But on this occasion I have a question to the experienced ones: do you need to buy any additional gaskets or o-rings when you are getting there to the diaphragm?

I have this diaphragm in my spares box at hand, but maybe I also should have a couple of "accompanying" items?