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-   -   500E gear selector rattle (http://www.peachparts.com/shopforum/tech-help/48699-500e-gear-selector-rattle.html)

seacoast_benz 10-21-2002 07:30 PM

500E gear selector rattle
 
I came to a realization late last night, driving the 500E home from dinner with friends, on a long straight empty stretch of I-280: boy, do I love this car. Wow.

As near to automotive ideality as anything I've ever owned and driven. But there is one minor annoyance I'd like to nail down -- in fact, it is the only thing wrong with the car, everything else is perfect!

Under mid to full throttle, there is a pronounced buzzy rattle from the center console, in the vicinity of the gear selector. Resting my
fingertips on the shaft of the gear selector, it seems to be from that.

It's not the shaft buzzing against the edge of the selector slot, which was my first impression. If I tip the shaft a mm or so out from the edge, the sound remains.

Last time the car was serviced, the advisor noted a worn transmission linkage bushing. At the time, I had been aware of the buzz/rattle, but the two didn't connect in my mind.

I asked him if it was in need of urgent service, since we were on a tight travel schedule, and he said, "No, it's just a bit loose, it would be quite a while before it would cause any trouble. The 60K service would be a fine time to fix it." So I rolled it off and haven't thought about it until now.

Wonder if a loose bushing might cause the rattle? If I recall, there are two of the things, and Guido says that they would be kinda tough for a shade tree mechanic to put on the car.

s/b

Benzmac 10-21-2002 07:34 PM

If the bushing fails, it IS the rattle.

seacoast_benz 10-22-2002 02:49 AM

Roger wilco, Benzmac. Thanks for the note!

Off to do some lookups on PartsShop. As I recall prior posts on the subject, the trans linkage bushings themselves are stupidly cheap items, they're just hard to put on.

I might end up pricing my time on this and having it done by a pro wrench. Just putting the 500E up on full jacks and stands in the garage is a fair bit of work, since nothing else underneath needs fixing.

I'll post a report on this one once it's squared away.

s/b

Jerry Hudson 10-22-2002 05:53 PM

I don't know what year your 500E is, but if the shift linkage is anything like my 97 E320 it's easy to fix. I had the same rattle comming from my shifter that was driving me crazy. I pulled the console out and removed 4 allen screws that mount the shifter to the floor and found a broken bushing where the transmission linkage connects to the shifter. There is a spring loaded clip that needs to be removed with needle nose pliers and the bushing just snaps in place. The hardest part was unpluging the wireing connectors for the power windows. Start to finish....1 hour. Your 500E may be a little different but the concept should be the same. Good luck

seacoast_benz 10-23-2002 04:02 PM

Hey, Jerry, excellent info! Thanks.

My previous understanding had been that there were two bushings, and Guido talked about having to change one from the underside on his 500E. I assume that this internal one would be the second of the two.

I'll dig into the car this weekend and see what I can find in the console.

s/b

seacoast_benz 11-16-2002 02:34 PM

Okay, I did this job yesterday. Here's what I found:

The bushings on the 500E are both external: one at the base of the selector lever where it comes through the floorpan, and one on the lever that hooks over the rotating tang on the side of the trans body. The two are linked by a long removable rod, which is what the bushings are intended to cushion.

(I can't rule out that there might be a bushing in the interior console, as Jerry points out, but it wasn't necessary on this car.)

In this case, the rear (selector) bushing was completely gone. Front one was in pretty good condition, but I figured I ought to leverage the time investment in working underneath, as the parts are so inexpensive.

I found the notes in this post valuable:

http://www.peachparts.com/shopforum/tech-help/27670-sloppy-93-w124-shift-linkage.html?highlight=w124+console

Yes, it's pretty hard to work on, due to space. Tight quarters both front and rear. Having the car on a lift would have made this enormously easier. I did it on ramps in the driveway. No room for a creeper, so there was a lot of flipped-turtle squirming in and out from under. I recommend having a helper nearby to fetch forgotten or necessary items. I didn't have one and it slowed me down.

If working on ramps, exercise all safety precautions! The transmission goes into neutral, so you lose the small safeguard of the parking pin. I put an extra pair of ramps in as safety stands, locked both parking and foot brakes, and placed another car in back to avoid rolloff. Having a 500E come down on your chest would be a bad day.

A bright LED headlamp is an enormous aid. It's bloody well dark under a car. However, don't be a doofus like I was, and don't buy a unit where the battery pack is carried at the back of your head (where your increasingly sore skull will be resting on it).

Get one with batteries on the sides, and no clips or buckles in back. Your head will thank you a few hours later! You'll also want some clear safety glasses to keep crud from falling in your eyes.

In the rear, as noted, you'll want to put the selector in neutral. And block it off -- if your manipulations push the selector tang toward the back of the car, the actual console shifter will go *forward*, and can lock into Park, which will entail squirming out from under the car to fix. Don't ask me how I found this out.

The rod is held on to the selector lever by a clip. Easy to pop off with a long screwdriver. The clip was roadworn a bit, and so I replaced it preventatively. Two or three bucks, as I recall.

Once the clip is off, the rod comes off trivially. You'll want the rod OUT before you do the rear bushing, which is done in place. Every bit of obstruction makes that job harder. I attempted it originally with the rod in. No way.

Go to the front and remove the lever that connects to the external tab from the trans. This has a 10mm doubleheaded bolt (with washer, don't lose it). Extract the bolt, put it in your safe inventory area, and then pry the lever off of the tab. It's a heavy J shape which comes off straight to the side. Took me a few minutes to figure that out.

Once you've got that, the rod-and-J-lever assembly should slide out to the front. REMEMBER TO RECORD THE CORRECT ORIENTATION! It *will* go back together and back in to the car in an unfastenable mirrored orientation. Normally I take notes on this stuff, but I was rattled at this point and forgot.

Definitely do the front bushing on the bench. You'll want to remove the rod first. It's held in place by a clip identical to the one at the rear. This one was in good shape and clean, unlike the rear one, so I re-used it.

On mine, the original front bushing was good enough that it had to be cut out with a utility blade. I tried a few ways to squeeze the new bushing in experimentally, all of which didn't look very promising.

What I did was to go find a 7mm bolt and nut, two big washers, and a squat wide socket (18mm?). The socket is to give the bushing space to pop into on the far side as things tighten.

Assemble the stack with bolt, washer, bushing, J-lever, socket, washer, nut, and tighten until the bushing is in place. I used a light durable grease all over the bushing. This squeezed out alarmingly: those bushings are a tight fit.

Once the rod-and-J-lever combination is out, doing the work is really easy. Under two minutes.

Back under the car, the selector lever bushing has to be done in place. This is a tough one. Deep narrow space, partly occluded by the exhaust. I have seen long pliers recommended, but I worked
with standard-length needlenoses. Longer ones might have made it fractionally easier.

I first tried a washer stack without the socket. Also needed to go get a shorter bolt, 40mm. Nothing longer will fit. The socketless washer stack idea failed. The bushing really needs open space to pop into as it goes through the lever opening.

Went out and bought a couple of 3/4-inch inside diameter washers. I put two of them into the stack, so I had bolt-smallwasher-bushing-lever-twobigwashers-smallwasher-nut, again with some light grease. Assembling this stack with the lever attached to the car, in the small space available, is a bear. But once done, and tightened, the bushing was perfectly in place.

I don't have one of those "squeeze wrench" gizmos advertised on late night TV, and don't know if they're any good, but I can tell you that doing this tightening with a standard wrench is slow and annoying. Not a lot of radial space. This would be a good test for an SW.

Clean everything and slide the rod-and-J-lever assembly back in from the front. You did record the orientation when you took it out, right?

Fasten the front first. The J-lever is actually quite difficult to put back on the tang that comes out of the trans. And you want it firmly seated!

Also be sure that the switch behind the trans tang (a little arm about 1.5cm high that rotates concentrically and independently with the tang) mates to the J-lever. There's a small hole in the lever and a little tab in the switch arm which has to go into that hole. The little arm is the neutral safety switch, right?

The tang is rectangular and there are two rectangular ports aligned in the lever body at the curve of the J. I had to use one hand to apply side pressure, while the other hand reached back and grabbed the selector rod at the back, and moved the mechanism back and forth. Some assembly lube is also recommended.

The doubleheaded bolt is a good check that the J-lever is firmly in place. It won't go through until the clip seats properly. Remember the washer on reassembly. I can't recall the torque spec now, but tighten it prudently. You wouldn't want this coming off without warning.

The rod should easily re-mate with the new bushing at the rear with only finger pressure. I picked up the clip and seated it against the mount point with needlenoses, then gently snapped it in with fingertips. Rotate 360 to confirm it's solidly on.

That's it!

Test drive carefully, remembering to remove your safety stands and other measures before coming off the ramps. (Once, many years ago, I forgot this. Very red face.)

In this case, the new bushings make the trans feel factory new. Previously there had been excessive lightness of action and a bit of slop to the selector lever. Now it's firm and precise, feels as a Benz is supposed to feel.

The initial symptom of bushing trouble had been an annoying buzz at high (very high) speeds or hard acceleration. That is completely gone. The car interior actually seems quieter when even not in that regime, so the shifter may have been transmitting subaudible vibration, coming from the loose point at the back where the bushing was AWOL.

Is this a good thing to have done on your MB? If your car needs it, yes, absolutely. I had no trouble but someone else has noted that bushing failure can result in trans trouble. The selector could get into an intermediate state, they say, and damage the valve body. But it's worth it just for feel and sound issues.

Here's the cost upshot. Components are trivially cheap. Under ten bucks for two bushings and two clips. Plus a buck or two worth of bolts and washers for the squeeze job.

But I called Autobahn Motors for a quote on just this job, F and R bushings, and their service adviser instantly said, "$225, sir."

Geez. How do people *own* these vehicles for the long term and have to pay dealer shop rates? Absolutely extortionate.

It took me about three hours to do this job, exclusive of going to buy washers and the like. If I'd had more accurate and detailed instructions, such as these will hopefully be, I'd have had it over in maybe 60-90 minutes.

Now that I've done it once, I could get it in 30 to 45 minutes. If I were a pro wrench with a lift and every tool going, maybe 15 minutes. Frankly, a lot of the time was spent just figuring stuff out. I hope that this saves others some time and trouble.

s/b

pentoman 11-17-2002 03:13 PM

Quote:

Originally posted by seacoast_benz
Okay, I did this job yesterday. Here's what I found:
It took me about three hours to do this job,
s/b

Did that include the time for the write-up? :D Really comprehensive write-up, thanks for taking the time to write it!

Russ


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