Mercedes automatic transmissions

[markba633csi]

I've wanted an SL or SLK for a long time. Just wondering how their automatics hold up over time

 

[matthewsx]

Probably the least of your worries.

Mercedes-Benz SL500 Problems and Complaints - 40 Issues

Problem with your Mercedes-Benz SL500? Our list of 40 known complaints reported by owners can help you fix your Mercedes-Benz SL500.

repairpal.com

But, if you want one you should get it. YOLO

Classic?

1981 mercedes 380sl for sale by owner - Sunnyvale, CA - craigslist

1981 Mercedes-Benz 380SL Roadster with 175.000 original miles on the odometer. It has a V8 engine coupled to an automatic transmission, leather interior, power windows, alloy wheels and both a...

sfbay.craigslist.org

or modern?

1996 mercedes benz SL320 for sale by owner - San Jose, CA - craigslist

For Sale: Low Mileage Mercedes SL 320 V6 - very reliable and with good gas mileage · Drives straight, clean inside, no leaks, no rattles or strange noises. Everything Works: AC, Engine has no...

sfbay.craigslist.org

Luxury cars can be had cheap if you're willing to do some work yourself. My old boss has one that he got for a few grand, had problems with the adjustable suspension and some other things I think.

John

 

[MikeInOr]

I have a 1980 450SLC and the transmission is pretty much a tank. The biggest problem I have had is the CIS fuel injection. It is a mechanical fuel injection which is very expensive to repair once it starts having problems.

 

[markba633csi]

The SLK is my favorite- many examples are high mileage nowadays so that's why I was asking

 

[MrWhoopee]

I have a 1980 450SLC and the transmission is pretty much a tank. The biggest problem I have had is the CIS fuel injection. It is a mechanical fuel injection which is very expensive to repair once it starts having problems.

I have a client who repairs the old Mercedes mechanical fuel injections in a very unlikely looking garage shop. He inherited the business from his father and tells me he is just about the last one left who still does them, the last few have died or retired. They are shipped to him from all over the world and he has them stacked up, waiting to be worked on. He's a very relaxed, casual kind of guy. You could wait a long time.

 

[455dan]

I've wanted an SL or SLK for a long time. Just wondering how their automatics hold up over time

Our 74 280 C' s auto still working fine the Quadra jet 4 barrel copy Mercedes used not so much.

There was a 230SL in the family (a 4 speed) and I missed a shift at 55 MPH 3-4th and I actually managed to break a gear.
It was cheaper to buy another complete trans out of a wrecking yard than to rebuild it. I had a 240D with a manual as well never had a shifting problem with it , but managed to destroy dads ( I did R&R it.) I can't speak to the newer generation MB's

Prices on used Mercedes parts seem to have sky rocketed in recent years. Definitely have the car looked over closely before handing over the green. Repairs can get Expensive.

Best wishes on securing a "Good" One.

 

[MikeInOr]

I have a client who repairs the old Mercedes mechanical fuel injections in a very unlikely looking garage shop. He inherited the business from his father and tells me he is just about the last one left who still does them, the last few have died or retired. They are shipped to him from all over the world and he has them stacked up, waiting to be worked on. He's a very relaxed, casual kind of guy. You could wait a long time.

I replaced the CIS mechanical fuel injection system in my 1980 450SLC with an electronic fuel injection system. With the wideband O2 sensor feedback it runs so much better than it ever did with the CIS system. I used a public domain based (at that time) fuel injection system called MegaSquirt to retrofit my 450SLC. CIS stands for "Continuous Injection System". There is no injection pulse, fuel is constantly poured into the intake at a mechanically metered flow rate. CIS is some times colloquially referred to as "drizzle injection".

There are very very tight tolerances in the CIS fuel system that controls the fuel flow and no new parts are available to replace worn parts. When I did the EFI upgrade about 15 years ago repairing the CIS system cost more than the car was worth. Since repairing the CIS meant swapping bad parts with parts that are less bad the life expectancy of CIS repairs is pretty dismal.

Mercedes had developed electronic fuel injection and put it in a couple of production cars before before they switched to the CIS mechanical fuel injection system. The original Mercedes EFI was a completely analogue fuel injection system (no computer). All modern fuel injection systems are, of course, digital (computer based).

Mercedes had several interesting engineering implementations back in the day. For example the power locks on the doors on my 1980 450SLC are vacuum based instead of electronic.

 

[tim81]

If I would have had a Mercedes here would have been the 1986 200d all mechanical and was a tank I miss one so bad now.

 

[455dan]

I have a 1980 450SLC and the transmission is pretty much a tank. The biggest problem I have had is the CIS fuel injection. It is a mechanical fuel injection which is very expensive to repair once it starts having problems.

Yep, the CIS Bosch "K jetronic" system was Trouble. Can't believe it survived into the 1990's.

VW used the same thing (in cheaper form) on the Rabbits and Jetta's . The fuel distributor /air flow sensor was usually the problem, the clearances had to be so tight on the "pin" that the air flow sensor sometimes would not be able to move the air flow disc upward to push the pin upward during start up, so the fuel distributor would not /pass or inject fuel at the injectors.

 

[yarm2111]

I've wanted an SL or SLK for a long time. Just wondering how their automatics hold up over time

It depends on a transmission type and model year. I had to deal with 722.3 in 92 600SEL and 722.6 in 99ML430. Both are very good, but not without issues. 722.3 usually loses reverse after 150k or so miles, due to wear of the clutch plates. I repaired it, not a bad repair, but you need some special tools.
722.6 prior to about 99 - 2000 had brass bushing between input and and output shafts. This bushing wears out and transmission self-destructs. After 2000 MB used needle roller bearing, so no more problem.
Do you have more info on year and model?