220D transmission/clutch questions!

[abracadabra]

Folks-

Well I recently picked up a great old 220D. I've had a '76 240D on the 115 chassis for years, but she needed so much work that I started searching around for a new ride.
The big plus with this car is that it recieved a fresh factory engine with all the trimmings in 1985, and currently has only 115k on that engine!

I've got a great bunch of mechanics here in Portland at MBI Motors, they just did a bunch of work for me on this car, basic stuff that it needed like
motor mounts, some new brake pads etc.

So when I pick my car up the mechanic that worked on it mentioned that he thought my throwout bearing was going. He was pretty pessimistic and seemed to think my clutch was next, and maybe even my transmission was going out.

Now, up until this point I had driven the car with very shot engine mounts so the ride was LOUD!! After I got in the car from the shop I of course noticed some things about the car. The most obvious being the rattling sound that would come from the area of the clutch, the left front of the car. It was only noticeable when accelerating, say in the area approaching the shift to 2nd, or 3rd, higher RPMs. Just a rattle sound.

But the sound doesn't happen all the time.

And, some gears are hard to get into sometimes: 1st can be tricky, it wants to go into reverse, and if I go back in to neutral, let the clutch out, then try 1st again it will work. And 3rd is sometimes tricky, it won't want to go, so I'll go back to 2nd and then 3rd again.

And, sometimes when I get it into neutral and let the clutch out there is a buzzing/humming/whirring sound that happens until I put the clutch in.
Not very loud.

Now, I was told that if this was a throwout bearing it would be LOUD, and
especially when the car was in neutral. What gives? Should I look for another tranny? Or is this the type of thing where I might be able to drive for a long time before I need to do something about it? I've learned the
quirks and driving is fun, quite an adventure!

Any help would be great!!

mark in Portland

[rs899]

I doubt that there is much wrong with your transmission, but the noise changing when you push in the clutch indicates a throwout bearing issue. Sounds to me like a linkage or hydraulic issue that is preventing the clutch from fully releasing. I would inspect the linkage and hydraulics first (cheaper and easier), but I think you may eventually have to go into the bellhousing and fix the bearing.

Rick

[t walgamuth]

It also could be a bad clutch disc or pressure plate coming apart. Both could cause dragging while trying to engage gears.

[abracadabra]

Well the more I drive this car the easier shifting gets.

The noise I described earlier, the rattling noise at higer RPMs, is gone.
I do hear a whirring/humming noise still, only sometimes when I'm in neutral.
The real problem is getting in to first, which is sometimes only accomplished by going to neutral, letting the clutch out, and starting all over again.

I've done some searching on this forum and found that alot of folks describe driving a manual transmission diesel to be quite different than doing so on a gas car. I especially noticed a few posts which described starting out from a stop in 1st by letting the clutch fully out, then hitting the gas, which is very different from driving gas car which will stall without the gas pedal. I tried this out today, and it works but the car sure shudders ahead.....anyone else do it this way? Does everyone do it this way??


mark in Portland

[rs899]

It also could be a bad clutch disc or pressure plate coming apart. Both could cause dragging while trying to engage gears.

These are both noise possibilities- I had a spring pop out on a VW clutch disc that made a rattling noise for months beforehand (was THAT what it was?- duh-oh).

The hard- to- get- in- first is most likely hydraulics failing-look there first.

I drive pretty much like as in a gasser manual. Diesel torque helps, but ther's no need to be cruel to your engine.

[todds]

which described starting out from a stop in 1st by letting the clutch fully out, then hitting the gas, which is very different from driving gas car which will stall without the gas pedal. I tried this out today, and it works but the car sure shudders ahead.....

Uhh, that sounds really bad for the car. Just drive it the same as any manual shift car, the transmission doesn't care whether the engine in front of it is gas or diesel so why should you? If you want to be extra nice to your transmission you can learn to double-clutch:

http://en.wikipedia.org/wiki/Double_declutch

Some transmissions are just notchy or crankier than others. You can't expect a 30 year old Mercedes to shift like a brand new Miata. On the other hand they shouldn't be making any noise and shouldn't be hindering your ability to properly drive the car!

[t walgamuth]

Thats how I drive a diesel. The torque is so good that unless I am in a hurry I just ease out the clutch and then step on it. No abuse there....just less wear on the clutch.

[rs899]

Thats how I drive a diesel. The torque is so good that unless I am in a hurry I just ease out the clutch and then step on it. No abuse there....just less wear on the clutch.

Hmm- I have never really tried this, but might be useful for trying to teach SWMBO to drive the 240D. Perhaps if one had the idle adjusted higher...

Tom, you must be the only guy on the road....

[todds]

Hmpf, well, I guess if the car isn't bucking or stalling out it can't hurt anything. I've only been able to do that smoothly on a motorcycle, guess I never tried it on the 240D I owned. The only thing that seems off is the shudder that was mentioned.

Anybody ever tried speed matching and shifting w/o a clutch as described below? I've done it going out of gear into neutral before but never into gear.

"Here is an experiment for you. Go out on a road where you have some room. Put the car in third and go at about 3000 rpm. Maintain speed and see how fast the engine is going when you shift to forth. let's say it is about 2200 rpm. Now go back into third at 3000 and put a little pressure (one or two fingers) on the shifter toward neutral. Don't depress the clutch. Nudge the accelerator a little to remove the tension between gears, and the the stick will move out of gear, into neutral. Take your foot off the accelerator, and put a little pressure on the stick toward forth gear. When the engine rpm drops to 2200 rpm, the stick will probably slide into forth without you ever pressing on the clutch. If you miss, and the engine rpm drops below 2200, just give it a very little gas to get it back to that speed. When the engine speed matches the road wheel speed, it should drop into gear. That should illustrate how it works. Be real gentle with the shift lever, and you won't hurt anything. Push too hard, and you will hear a grind."

[sjefke]

I prefer to use the clutch combined with the little gadgets called synchromesh rings instead of throttle shift-grinding-gear change It would also depend on the gear ratios (I think) to know what RPM for no clutch shifting would actually be correct for the different MB models.

Regarding original question, rattles do not come from hydraulics. It may be an old throwout bearing that had some slight corrosion on it from standing and now with more use is starting the clean out a bit and run smoother/looser. Pressure plates are pretty strong. Bearings go first. A worn plate you will feel slipping first when you step on gas. If you are capable of unbolting the transmission from the car, then replacing the release/throwout bearing is pretty easy and cheap ($50 for the bearing).

Rough shifting between gears could be related to old synchromesh rings. Rings are not that expensive (relatively speaking...), but you do need to take apart the tranny so labor is going to kill you.

Bleed the clutch first (if it still shifts rough). Also check whether the slave cylinder is loose. Even a couple of millimeters of movement cause bad clutch behavior and no bleeding is going to solve that. Happened to me (see some old post from me a while go). I went nuts trying to find the problem after replacing the master cylinder and bleeding the system for the n-th time.

Good luck. Manuals are fun!

Bert

[abracadabra]

Well I gave some time here before posting again to really study and assess the situation.

So yes there may be a bearing issue here, although I have read that these old Benz transmissions are little noisy sometimes, that you might hear the whirring of gears under the car when the shifter is in neutral. I only mention this because I've read various places that when a throwout bearing is going bad, its very loud. The noise I hear when the clutch is out and the shifter is in neutral is not that loud and is constant.

The rattling I mentioned in the first post is gone.

Now, the main issues are still the fact that sometimes it takes 2, 3, or even 4 tries to get 1st gear from a stop. No grinding, it just doesn't want to go in so I go back and let the clutch out and try again until I succeed.

I've also been alot more patient with shifting, not rushing things, to see if that would help with getting in other gears. I still have a consistent problem with getting in to third gear, maybe every 3 or 4 times I go for it , it won't go all the way and usually going back to 2nd and trying again doesn't work anymore. And today for the first time I could't get it in to 2nd at one point (the first time this has happend!) .

And, its still usually pretty stiff getting it out of reverse, it goes in to reverse easily, but is hard to get out.

So, the clutch seems fine as far as not slipping at any point and not popping out of gear.

I wonder what effect old/bad/low transmission oil would have on all this? I plan on changing this as soon as I can, who knows how long its been since this was changed last!

And, could the problems I'm having also be related to loose linkages and/or
worn linkage bushings??

Ya'll have been helpful thus far! Thanks! I'm just trying to figure out this transmission issue before dumping more money in to the car.

Oh, I love this car! Its a blast to drive, a '72 220D with 110k on a factory rebuild, new tires, brakes , good body, good interior, but what the heck is up with the tranny??

thanks!

mark in POrtland

[todds]

sometimes it takes 2, 3, or even 4 tries to get 1st gear from a stop.
...
I still have a consistent problem with getting in to third gear
...
today for the first time I could't get it in to 2nd at one point

This isn't right, even the least refined Benz tranny shouldn't cause this kind of trouble. It sounds kinda dangerous to me, in an already slow car, not to be able to shift at appropriate times. At the very least it'll seriously hinder your enjoyment of the car, I'd recommend spending a few bucks and getting a professional assessment of what's up. Then decide if you want to fix it yourself or not.

In an old alfa with a similarly cranky 1st gear at lights I used to come back and just barely touch 2nd or alternatively let the clutch out a hair and it'd slot right in smooth as butter, but it was nowhere near as bad as what you describe.

[sjefke]

First, bear in mind, these transmissions are not quick shifters. Compared to my MGB, my MB transmission shifts like a truck.

My car has occasionally trouble getting into 1st as well, but only when the engine/tranny drivetrain is really, really hot (I suspect hydraulic fluid loosing a bit of pressure due to increased fluidity). Problems like you have are definitely not normal.

I also have small whining/whirring in neutral. But remember that the input shaft of the tranny is always connected and running EXCEPT when you press the clutch and depress/release the pressure plate spring, so you may hear the main input bearing whining a bit (I have that when cold - changes when tranny warms up).

Transmission oil can be an issue and is easy to check. Make sure it is topped off to the plug level, or not far below it (just unplug the side plug and stick your finger in it to feel), but do get a professional opinion from somebody who can judge what is going on. And make sure they know this kind of transmissions because it is easy to spend a lot of money. I suspect you may need some new clutch hydraulics (slave and master). Check whether you see any droplets or wetness along the slave and master cylinders and the lines. The problem is, you often only find out what the true problem was AFTER you replace the parts.

Good luck,

Bert

[rs899]

I think it is mostly weak hydraulics...the "hard to get OUT of reverse" is the key to me.

[abracadabra]

Yeah the more I drive this car and understand how the system works and REALLY take keep a keen eye on the sypmtoms it does seem like the hydraulics of the clutch could be at issue here.

In fact, there have been a few times that I've noticed letting the clutch out in neutral at a stop where I thought, boy , that let out kinda funny, it just didn't feel right to me.

I'm actually pretty used to driving old truck like tranny's, I had an old VW Squareback for years and that had a very slow but very functional transmission in it. This one......not so functional! Its gotten to the point where I don't drive it because I don't want to damage anything internally with gear grinding.

So, what would parts cost if I'm looking at a worse case scenario and need master/clutch cylinders? How hard is the labor, could I do it myself? I've done a ton of routine work and can do brakes and have even pulled an engine out of a VW and had cylinder head work done.....but I'm married now and have a young son so that sort of thing is out of the question.......!

Well when I get a moment I'll check the cylinders for leakage.....and see if the slave cylinder is loose.....I'm actually not sure where the slave is, but I'm sure I can find it by tracing the line from the master......

Thanks for all the help so far, I can't wait to get this problem sussed out because this car is REALLY fun to drive, maybe the best ride I've had. And if this turns out to be something that can be fixed without a major clutch/transmisson bearing issue, well , that would make my day!

mark in Portland