shimmy/pulsation in 1997 w202/c230
 

I have a shimmy, or pulsation - wouldn't really call it vibration - in my car and I don't know where to start. When going 10-15mph it feels as though the car is bouncing up and down, like the road is uneven. The faster you go, the headrests and visors can be seen shaking. It's akin to the feeling a bent wheel gives you. It's a Starmark-certified car with new Conti's, and I just had nearly the entire front suspension - minus shocks and springs - replaced for squeaks. They rotated and balanced the tires when they did this, and it hasn't changed. I'd like to think they wouldnt sell the car with a bent wheel, especially considering it has new tires and they have now been on the balancer twice. I've read about rear diffs and flex disks. Any ideas that I can use when I take it to the dealer? TIA.

Do you feel any vibrations in the steering wheel or in the seat?

Can you estimate the frequency of the pulsation? rapid as in multiple per second or one per second.

any noise?

dependent or independent with amount of throttle at a given speed if you drop down a gear and maintain speed does the pulsation change.

only recommended for this test but at the pulsation at 15 - 20 mph or the shaking at greater speed what happens if transmission put in neutral

does it occur at different rpm?

mileage of car

what happens when observng engine with hood open and someone takes car through rpm range in neutral. park, drive with brake applied - only for test?

Conti tires seem to cause problems particularly the ones produced in the US

if you do a search on this site under Conti you may get some info

plus I hope the dealer is not missing a defective shock

Q:do you feel any vibrations in the steering wheel or in the seat?

A: Minor, but yes. More noticeable are the shaking headrests and visors

Q:Can you estimate the frequency of the pulsation? rapid as in multiple per second or one per second.

A: Multiple per second, regularly-spaced.

Q: any noise?

A: none

Q: dependent or independent with amount of throttle at a given speed if you drop down a gear and maintain speed does the pulsation change.

A: has to do with speed - car feels as if it's going over miniature speedhumps at low speeds, regularly spaced, and then it turns into more muted but faster shaking as speed increases - like something is out of balance, or something in the suspension isn't doing it's jjob.

Q: only recommended for this test but at the pulsation at 15 - 20 mph or the shaking at greater speed what happens if transmission put in neutral

A: Haven't tried it

Q: does it occur at different rpm?

A: happens at some form at all speeds

Q:mileage of car

A: 68k

Q: what happens when observng engine with hood open and someone takes car through rpm range in neutral. park, drive with brake applied - only for test?

A: haven't tried

I'm totally unqualified to say, but my best guesses, in order, are:

1-belt tensioner and damper
2-water pump
3-transmission (not really but see below)

All of these are 100% covered under your Starmark. Take it to the best dealership facility around, forget about cost, tell your service adviser "it's shaking", be cool about it, and ask when you can pick it up.

BTW, if I were you, with the goal of MBUSA installing a new, updated transmission, I'd try to have the transmission declared problimatic. If you search under 722.6 I think you'll see.

Good luck and best regards,

Thanks guys.

I noticed this morning it does happen in neutral as well. So, I guess that rules out the drivetrain.

As for the trans, it does have occasional hard 1-2 upshifts, and it slips at least 3x daily starting out in 1st. Is that enough to get it declared dying?

That "slip" is your ticket to a brand new, updated transmission. If you had to buy it yourself, it'd set you back about $6,000. If you search, you'll see the early 722.6 transmission (the one you have) is the weak link of W202. A new one should be smoother and last for the foreseeable future. Congratulations!

While the engine and emissions system are warming up, a fairly hard 1-2 shift is normal. After warm up, except under very heavy load, it's not. When you describe your transmission concern to the service writer, I'd only mention the harsh shifting if it occurs after warming up. It's the slipping that's the sign of failure.

http://www.peachparts.com/shopforum/tech-help/74279-new-722-6-tranny-w202-c230.html?highlight=722.6

Thanks Mike,

Yeah, I'm familiar with the issue. I just didn't realize that I already had the signs of failure. I remember now that my grandmother's pre-6/98 E320 had its trans replaced around 30k for being "rough." At the time, in 2000, it seemed a little extreme, but now I understand why it was wholly swapped.

This still doesn't solve my shimmy. I guess I'll make an appt to have both looked at. Oh yeah, and if they don't swap it for whatever reason, should I get the fluid changed, or is it pretty certain that it will flat-out die before 100k if it was already slipping at 60k?

If it were me, I'd schedule an appointment and let them know you expect both issues to be covered by Starmark (and if not, to have the manager call you to "discuss" it. I'm maybe a little too direct, but I'd tell the service writer about your E320 transmission experience, that you know about the 722.6 problems, and that you expect the same resoluion that was done for the E320, ie a new tranny. It doesn't cost the dealership itself anything (in fact I think they make a profit on the work), so let them worry about it with MBUSA. As for tranny fluid, I think you'd have a hard time convincing the dealership to change it, since MBUSA says it's "sealed for life."

Good luck and enjoy. Best regards,

news from the shop
 

well, I took it in today and described the issue to the shop foreman, who I've worked with on some issues before. They are replacing what my service advisor termed the "conductor plate" to resolve the occasional 1st gear slip, and I am getting a free fluid and filter change (!) which I am happy about. I inquired about them adding a magnet, like the updated 722.6 has, but the tech claims that can't be done. Why not? Either way, he says fluid changes should be done every 50k, and I am at 69k now. I feel pretty good to be getting it changed at this point. Tech says the slip should not have damaged any internal components.


As for the shimmy, they are keeping it overnight to check the (OEM Conti) tires in the morning. Defective tires were a concern of mine.

Thoughts on all this?

Sounds good. Good luck with it. I'm really curious what they say is wrong, how they end up fixing it, and if the fix really works. After you pick it up, would you please post what's up?

you should ask if they are removing the pan to change the filter, btw that magnet is a $2.50 part

I just purchased a set of Conti tires and two were out of round.
Got two more to replace the out of round and they were also out of round. Finally purchased Yokohama's. Very good.

out of round rims
 

I have the same problem on my ford F250 truck. Actually threw out a perfectly good set of tires trying to issolate the problem. Turns out its the tire rims. When I put them on the tire balance machine, i could see the rim moving up and down about a 1/4".

My symptoms where at low speed, the truck seemed to gallop up and down slightly. At 60mph, everything inside the truck vibrated.

Good luck

Ron

That hop at low speeds and vibration at high speeds is what I'm getting.

Just got the call from the dealer. Tech claims he cannot duplicate the problem. I say fine, I guess I'll drive it until it gets worse. They are bringing my car to work because they are short on loaners - interesting. Anyway, trans conductor plate they said had one failed RPM sensor, so they replaced that, and I'll report back after I drive it.