I have an '82 240D with 211K miles that has developed an automatic transmission shifting problem.  Until recently the transmission always shifted smoothly and properly as I accelerated ( I use that term loosely concerning the 240D ).

Now it seems that the engine needs to reach the target speeds indicated on the speedo (22MPH, 37MPH, & 60MPH) before the transmission will shift from second to third to fourth, respectively.

I have changed the transmission filter and fluid *twice* to make sure things are really clean, but the problem still exists.  I suspect some sort of vacuum problem, but I don't know what to look for, or where to look for it.

Any ideas?  Thanks in advance for any help!

- Fred

Fred,

I had the exact same problem on my 82 240D.  After changing the transmission fluid and filter, and the problem still existed, I found a cracked rubber vacuum connector on the vacuum line from the transmission.  As I recall it was in the engine compartment between the engine and the firewall.  Trace the vacuum line from the transmission to the last point of the vacuum source.  Any leak in the vacuum line will cause the transmission to shift rough or at higher rpm's than normal.  Also, if this transmission has a vacuum modulator, that could be the culprit, but usually transmission fluid is sucked in the engine via the vacuum line and you would notice a consumption of trans. fluid. Hope this helps.

Man do I miss that car.  After 8 great years, my wife totaled it when a guy pulled in front of her.  It was 9 years old with 79,000 miles and I had just put on 15 coats of lacquer with clear and hand rubbed it to a mirror slick shine.  Oh well....the car crumpled just like it was design to...and I still have the wife. 

Good Luck,

Dave

Fred,

Another great site for Mercedes technical help is:  www.bentleypublishers.com/

Go to Technical Discussions and select the 240D/300D forum and you can get excellent advice.  I have found this site to be extremely helpful.  Also, there is no charge for this site. 

Dave

Thanks, Dave.

I traced the vacuum line from the EGR switchover box on the cam cover down along the top of the trans to the modulator and everything looks OK.  I ordered a new modulator for $43.07 and a new vacuum cap for $1.64 from The Parts Bin (http://www.thepartsbin.com) this afternoon, so I'll know in a few days if this fixes my shifting problem.  Looks like getting to the modulator valve is going to be lots of fun ...

I feel the same way about my D.  It was kept like a Ferrari by the previous owner, and it still has the original paint that could pass for 5 years old.  I took my brother-in-law for a ride out to the local Beer depot last weekend and when he sat inside the car he said "How old is this car again?  It looks like new inside!"  That was cool.

I'll post the modulator swap results here when the outcome is known -- thanks again for the help and support links.

BTW, I've never known anyone to put such effort into the paintwork on a 240D; that must have been a special car.  The most outrageous thing I've ever seen was a Mustang GT 5.0L + Tremec 5-speed transplant into a D.  Talk about a sleeper!

- Fred

'82 M-B 240D 211K * '86 Porsche 944 turbo 54K * '70 Triumph Bonneville 650 *

Fred,

I was looking at the records that I still have from the 82 240D, and about 2 years after I found the vacuum leak that was affecting transmission shift, I had to replace the vacuum modulator.  As I recall, the change out wasn't that difficult.  Coincidently, I just had to replace the vacuum modulator on my wife's 190E yesterday.  It started sucking out trans. fluid last month and was not shifting properly.  Now talk about a tight fit.  After a tip from Chuck, a MB tech. that helps on Bentleypublishers.com, I was able to replace the VM with no problems.  As it turns out, to get to the VM I had to drop the exhaust from the rear of the car to allow the transmission to drop low enough when I removed the trans. crossmember. Now the car shifts like it did when it was new.

Good luck with your VM,

Dave 

Dave,

VM was definitely the problem.  I've ordered a 123 chassis service manual, but in the meantime do you have any tips on how to adjust the VM?  According to Kent Bergsma's Vacuum System Troubleshooting guide (Mercedessource) it can be a bugger to adjust.

Do you know how or should I just wait until the service manual arrives?  The manufacturer's note inside the new VM box warns of possible trans or engine damage if the VM is not properly adjusted.

- Fred

'82 M-B 240D 211K * '86 Porsche 944 turbo 54K * '70 Triumph Bonneville 650 *

Fred,

Glad to hear that the VM was your problem.  To tell you the truth, when I replaced my VM, I was satisfied with the shifting as it was so I didn't change the adjustment.  I was talking to a MB tech. last week and he said that he drives the car several times and adjusts the VM to get satisfactory shifting.  I would definitely wait until you get the service manual to adjust your VM.  By the way, how does your trans. shift now with the factory VM settings?

Dave

Having the same problem on my 1980 240D.....just bought it ...one look at all the oil soaked vacuum line and loose ill fitting  connector mess tells me a complete vacuum lineand connector replacement will set things toward the normal direction...at least stuff under the hood...just joined this site...fantastic! Good luck...kevin

I checked the new VM factory setting (as delivered) and the adjuster was set twelve (12) turns out counter-clockwise.  The old VM that was installed in my 240D was set to six (6) turns out counter-clockwise, and the shifting was satisfactory before that VM went bad.

Since I *still* do not have my service manual, I set the new VM to match the old VM.  As you would imagine, the car now shifts properly, and in exactly the same fashion as before.

Everything seems OK, so I probably won't try to microadjust the new VM at this point.

Mission accomplished!

- Fred

'82 M-B 240D 211K * '86 Porsche 944 turbo 54K * '70 Triumph Bonneville 650 *