Santron

Just bought an SL 500 and noticed that there is a slight "clunk" coming from the driveline when I decelerate, just before coming to a stop. I asked the mechanic about this when I had the car cheched out before I bought it and he said that many SL's do that. I'm not sure I believe him. Either way, the car is under warranty for the next 3yr/36K, but I'm wondering if I should take it into MB for their opinion. Anyone elses SL do this?

KevinJ

Hi, I have a '96 SL320 and I think you have the same noise as I.

If I reverse and then drive forward, upon braking I will hear this noise. I have heard another SL do the same thing and so assume this is normal.

It sounds like the noise is coming from both sides of the front

Might be worth finding out what exactly it is though.

Thanks

Kevin

Santron

Thanks for the reply Kevin. I will get it checked out, but I need to wait about a month or so before my extended warranty kicks in (I just bought the car and don't want them to label it as a pre-existing condition). I will definitely post what I find out here. The strange thing about mine is that it only does it when braking from high speeds (like 30+mph), and if I brake really gently it doesn't do it. But it is definitely a "clunk" coming from the transmission area. I had an old Chevy Z24 convertible that made the EXACT same noise as this for years, and it turned out that it was a broken transmission mount. I'd be curious if yours does the same thing as described above, but doesn't do it if you brake gradually. I can't imagine that MBZ would allow something like this as "normal" but maybe it's something harmless that happens to some of them after a while. I only have 44K miles on the car.

JunoJim

Sounds like a worn U-joint...

MrMajstyk

Hi gang! I'm a new member here, just joined a few minutes ago!
I just bought a 1996 SL500 Sport, triple black, chrome AMG wheels...completely stock, has CD changer and MB phone still in it. 93k miles, Starmark certified (but past warranty), I'm the 3rd owner. Pristine condition...and I LOVE it! What a car!

So...here's my only "issue" (so far, anyway)...when I am decelerating, coming to a stop, the car "clunks" when it shifts from 2nd into first. Seems like it's coming from the rear end somewhere. Sometimes, when I'm just driving gently, especially in the morning, its not that bad...but if I drive it briskly, it gets a bit worse. By the end of an hours' drive, it's there, regardless. It's not really bad, more annoying than anything else...but I do not want it to get worse.

I took it to a very reputable mechanic who ONLY services MB, upon the recommendation of the wholesaler I purchased it from. This guy knows his stuff! He drove it, checked it out pretty thoroughly (said the car was just awesome!)...and raised it up on the rack....inspected the "usual suspects", U-Joints, etc. He said the trans mount was broken and showed me...and then he did the test with the "foot-on-the-brake-step-on-the-gas" thing, and the motor raised WAY up off the mounts. SO...he replaced the tranny mount and the motor mounts. (By the way, the wholesaler paid for the tranny mount and split the cost of the motor mounts! Great guy!) The car needed them anyway...BUT...still the same "clunk" from the rear end upon decerleration from 2nd to 1st gear. Other than that, the car is awesome. It shifts smoothly and perfectly up through the gears, no noise or vibration...motor is just a powerhouse!
Any ideas?
I've researched a bunch...and I've seen responses like.."well, they just DO that"..to..."You should have that checked out". I'm taking the car back to the mechanic on Tuesday...he said he'd check a few more things...no charge!
Just wondering if anyone else experienced the same things?

Santron

Hey there , Mr Majystic

What you are describing is EXACTLY what my 1996 SL500 went through when I first got it. Mine only had 44K miles on it. Mine was doing this when I bought it, and I also took it to a mechanic who said that "they all do that". This is BS! They do not all do that. Mine ended up being a problem with the transmission and it had to be replaced, for about $6K. Mine eventually got REALLY bad and started banging around when accelerating and decelerating and I thought was bound to fail on me when on the road so I just bit the bullet and had it fixed. Here is my advice to you, though: DO NOT have the transmission rebuilt, have it replaced. I took mine to Bruce Strauss Autmotive in Orange County, which is THE premiere independent Mercedes place and has been in business for like 30 years and has a great reputation. They struggled with rebuilding the thing for over a year - yes, my SL was in the shop for 15 months. (I didn't care because I have another car and several motorcycles and the SL was just a toy). They rebuilt it like 5-6 times before they got it semi-right. I still don't think that mine shifts like it should. They ended up charging me like $5K or $6K but theeir real cost was a lot higher. For that same price you can get a new transmission from Mercedes and have it installed and be done with it with a factory warranty on the new trans. Anyway, sorry to be the bearer of bad new, and this may not be wat's happening with your SL, but it's is what happened to mine. Feel free to IM me if you have any other questions.

MrMajstyk

Wow...rebuilt 5 or 6 times...over 15 months...at a cost of 5-6,000.00...and it STILL doesn't shift the way it should???? Ouch!

From what you say, it seems like your guy KNOWS what he's doing...and its still a challenge to sort out the tranny on these cars! And I've read other posts here...and on other forums, about the transmissions, or related driveline componentry, in a lot of M-B cars (especially the ML) that have similar symptoms...but no results posted. I think you're right, I won't mess with "rebuilding", just replacement if necessary. Seems like it costs about the same either way. But, I wonder...if it's STILL not shifting right after all that....maybe its NOT entirely the transmission. This is interesting! Maybe its a combination of things...U joint, center support (or whatever they call it...and I've read about some 'control valve' or something too, but I don't know if it applies to this situation or not) or maybe even the rear differential.

OK...so I will go to my guy on Tuesday, and see if he has anything else to offer by way of explanation and repair, and I will post the results! Maybe we can save someone else the hassle and expense if we post our results.

I will have him check everything that could possibly be making this thing happen...except the transmission...and see if there isn't some other 'culprit' causing the "clunk". I'll save the tranny replacement for last if there isn't some other fix.

Wish me luck..I'm goin' in!

Santron

From what they told me ours (1996+) is the new electronically controlled transmissions. My guy had never seen one that did what mine did, so I guess the problem is rare. They wanted to try to rebuild it to gain experience with the newer transmissions, but in retrospect I wish that I had just had it replaced. Not that mine shifts badly, just sometimes it does weird stuff that probably no one else would notice. If I had a NEW trans in there, though, I wouldn't have doubts.

Good luck with yours abd post back and let us know what happens..