Toronto300E

Hi. My 1987 300E won't shift out of 1st gear some of the time. When it doesn't I notice that I can still drive faster than it would normally in first gear but the RPM goes really high like when I go past 40mph (65km/hr). So, I don't do that and have relegated myself to city driving at about 30mph max. Sometimes, for a few weeks or so it does shift into higher gears but I still don't go on the highway because a few times when I did the car would suddenly shift down to 1st gear when I was going 50mph (80 km/hr).

Does anyone have any idea what might be happening and what I can troubleshoot? I've searched the internet with no luck.

Thanks.

QVHK

Seems like gearbox is toasted, not uncommon if car is nearly 25 years old. Was it overhauled before, and have you checked gearbox oil level? Moreover, it sounds strange that you normally drive off in 1st gear rather than "D" drive where the car normally rolls off in 2nd unless you floor it and it then engages 1st gear for maximum acceleration.

Toronto300E

Sorry I was meaning Drive not 1 - I can't seem to get out of that first gear when I start driving with the shift at D.

The car was never overhauled, has about 243,000km on it (150,000m or so) and I have not checked the gear box oil level but will if I can figure out how.

I did just find some info that the following could be causes:

- RPM sensor malfunction
- control pressure cable problem
- broken vacuum line
- kickdown switch defective
- governor adjustment

But I really haven't a clue about any of these.

lowesguy

Change trans fluid and filter,order k1 shift kit from dealer 10 bucks,fixed mine at 230k,now shifts great! before would shift at 4k with a bang!

Toronto300E

I'm a handy guy but have never done this before and was not able to find instructions anywhere on how to install the new shift kit.

I am bringing the car to my mechanic tomorrow to see what he says.

Toronto300E

I'm a neophyte with cars. I assume by gearbox you mean transmission? If so, yes the transmission fluid (I didn't know it was also called oil) is ok.

QVHK

Yes, I meant transmission. There is a dip stick near the firewall. Check transmission fluid level first. Replace/top up as necessary before considering other more costly fix.

Toronto300E

The transmission fluid is definitely where it should be (and was entirely replace about 4 months ago). My mechanic is good, but he keeps telling me to get rid of the car. Yet, repairs here and there seem to keep it going. My worry is he'll just make a blanket statement about the transmission being shot and not really check all the things I mentioned above that it could be and I have no way of knowing if he checked those or not.

kluvsbenz

I was told the same thing by the dealer because I didn't buy a grocery list of parts he wanted me to get for my 90 300E. I put fuel pumps on but it wasn't a fuel system problem. It was the freakin' spark plugs!! I think you should find someone else that you can work with. Some mechanics can be finicky.

Toronto300E

Well I am getting tired of being told to get rid of the car. It runs like the day I bought it (in drive and when it does manage to shift to the other gears). Today I drove on the highway at 90km/hr and it drove fine as the problem is intermittent. Engine oil leaks from my car which makes the spark plugs need replacing every 6mos-yr, so I learned how to do that myself and I just replace all of them every 6 mos now for 1/5th the price the dealer charged for parts+labour. I also check the oil every couple of weeks (tends to need about 1/2 qt/month if I am driving a lot). I also know how to top up all the other fluids.

I don't understand why a mechanic would not want to work on my car given he is getting paid by the hour and also for the parts. My philosophy is that even though it costs me about $2,000 a year to fix the car (twice or more the value of the car), it means I don't have to shell out $65,000 with tax to get a new Mercedes 3XXE, especially since I ride my bike mostly and only use the car maybe 1 day a week.

Nor do I worry about dents and scratches with my old Mercedes!

QVHK

I may be wrong, but the W124 has a mechanical transmission so the problem is unlikely to be caused by electronic sensors. If fluid level is normal the transmission is the primary suspect due to age and mileage, but you may well want to seek a second opinion from a mechanic who is knowledgeable about older Mercedes.

Toronto300E

I guess I am hoping that it is something different other than the transmission itself given that the car only has 243,000 km on it (151,000 miles). But, as you indicate, age is also a factor in addition to mileage.

Toronto300E

Well it turns out that I had a problem with the driveshaft (it was making some shuddering and banging noises for the first 10 seconds or so when I started driving but not if I accelerated very very slowly) and it turns out the flex discs needed replacing so my mechanic is doing that as we speak. I also replaced the spark plugs myself with new ones before I brought it in. All of the fluids have been topped up and the oil filter and oil changed.

So, we'll see if I continue to have problems with shifting into other gears. If so, I am going to go through the items enumerated one-by-one in my post #3 above and find a Mercedes mechanic that can troubleshoot the transmission problems instead of the one I have who just keeps telling me my transmission is shot and to junk the car.

Does anyone know of a good Mercedes mechanic in the Toronto, Ontario, Canada area who is good at troubleshooting transmissions?

QVHK

Hmm, the flex disk might explain the noise and vibration but probably won't explain the inertia in gear shift. Is it the torque converter or something, if not due to inherent problem with the transmission?

Toronto300E

I don't know why the transmission intermittently doesn't shift, but I got the car back from the mechanic and not only were the flex discs worn so both the front and back ones were replaced, but the center bearing carrier was shot, so that was replaced too. And then when they took it out for a test drive they noticed a noise from the engine area and lo and behold one of the hydraulic engine mounts was shot and it turned out to be the driver's side one which is a lot more labour to remove and reinstall. It was $360 parts + 3 hrs labour @ $112/hr = $360 + $336 = $696 + tax to replace the flex discs and carrier and $50 part + 3 hrs labour @ $112/hr = $50 + $336 = $396 + tax to replace the driver's side hydraulic engine mount, so a total of $1,092 + tax to do this. Did I get hosed?

The transmission is currently shifting properly and with all these things replaced including the spark plugs changed, all fluids topped up and the oil and oil filter changed we'll see what happens in the next while. The mechanic told me to bring the car back in when the tranmission starts not shifting again and consistently doesn't. Then he said they'd go through checking all the things that could cause that and try to narrow it down. Hopefully it won't be the transmission itself.

Thanks for everyone's help. Now I am going to reinstall my old Becker 754 radio (to replace the Sony radio with CD changer that is shot) and replace the rear two window motors that haven't worked for a while myself (but will make sure it's not the switch first). All that is not working other than that is the A/C which I don't feel is worth fixing given I don't drive the car more than once a week (but then it was 80F here in Toronto today!) and the drivers seat no longer moves forward or back (but the back rest does go forward and back), so I am going to try to trouble shoot that too.

I just love my 1987 300E and want to keep it as long as I can. It now rides like the day I bought it in Aug, 1987.