SLK 200 Gearchange - Is this normal

[Richard Horsfall]

I have a 2001 SLK 200, and although I love the car generally, I find it difficult to pull away quickly and smoothly, (as I would expect from a sports car). It seems that you have to ride the clutch with plenty of revs to get away reasonably well. The next problem is changing from first to second, which is very irratic, and far from smooth. Sometimes I have to dip the clutch back in, to avoid kangaroo juice.

I have had it checked out by the Mercedes Dealer, and they say that there is nothing wrong.

Has anyone else experienced similar problems ?

 

[davealtree]

SLK 200 Gearchange

I must admit I found my 190e manual had a modest gearbox and transmission....I found the old sierra a better change!  Never tried an SLK though!!

 

[Tony]

SLK 200 Gearchange

I know exactly what you mean because I had the same problem and just got the run-around from the dealers. I finally got some answers though.

First you need to check the oil level in the box. The 6-speed box has the level hole set too high - by which I mean that if the box is filled until the oil flows out, it's got 300 ml too much oil in it. There's a technical note that came out of Stuttgart to this effect but a lot of dealers are unaware of it. You may not think that 300 ml of oil would make much much difference but believe me it does (especially in the 1 to 2 change, where the over-filled box seems very reluctant to come out of first).

Next thing is that the box takes a long time to free up. They're built very tight for some reason and it'll take a minimum of 10,000 miles before the stiffness wears off.

The third thing is the oil in the box. Mercedes put Chrysler 75W-80 non-synthetic oil in it. I've changed mine to 75W-80 fully synthetic oil (Redline MTL) and this makes a very significant improvement. The notchiness has gone and it's also much lighter (especially when cold, because synthetic oils retain their correct viscosity over a wider temperature range).

I think you'll find that correct oil level, synthetic oil and a bit of usage will transform the gear change. There are a couple of other problems that then need putting right. First the clutch take-up is a bit fierce (it goes from nothing to full grip over a very short travel). Second the throttle is non-linear (there's a longish travel with little engine rev increase followed by a short period where the revs rise rapidly. The throttle is drive-by-wire so it needs a software mod which isn't available. Mercedes use the same code for their auto boxes, so it's basically a manual with kick-down !). Also the spring on the throttle is too strong. These problems conspire to make it difficult to drive smoothly, but you do get use to it. I;m going to investigate having a weaker throttle spring put on the accelerator - again the one used comes straight from the automatic.      


(Edited by Tony at 9:22 am on June 21, 2002)


(Edited by Tony at 9:22 am on June 21, 2002)

 

[Arnie]

SLK 200 Gearchange

Although Mercedes is improving with Manual Geaboxes, it's never been their strong-point. Most of their cars are designed and setup with Automatic transmissions in mind, and in this respect, they are the best in the business. If you want to drive a good manual transmission, drive a BMW; if you want an auto, drive a Merc.  (Pity, because the SLK is in every other respect better than the Z3.)

Although, as I said, Merc seems to be paying more attention now to such things, as you see from their change to rack-and-pinion steering etc. in their newer car models.

Change of oil and a good running-in should, nevertheless, help improve the gear-change. As for the clutch, a sharp biting point is good if you have a powerful engine with good low-down torque, otherwise a softer take-up would be better. Hope that Merc realeases new software for the Throttle (didn't realise they were electronic.)



(Edited by Arnie at 9:15 am on June 21, 2002)

 

[Tony]

SLK 200 Gearchange

The thing is that Mercedes will always have a bad reputation for manual transmissions if they deliver cars for motoring journalists to review with the wrong oil, the wrong oil level and built so tight that they need running in. When you read the reviews of any Merc 6-speed manual they either try to avoid mentioning the gear change or say that it's c*!p. I remember reading a review of an SLK320 manual by Jeremy Clarkson where he said that he didn't know what oil they put in the gearbox but he suspected it had been mixed with a liberal amount of concrete. He also said that he refused to believe that it had a reverse gear ("only engageable with the help of a JCB") and that the only woman who would be able to change gear on the car was Martina Navratilova.

Even the Mercedes dealer I talked to said that it was my fault for buying a manual because Mercedes can't make manual transmissions (!).

I also remember a comparison test on Channel 4's Driven where they compared the SLK320, the Audi TT225 and the Alfa GTV V6. Mike Brewer drove each car round some race circuit (I forget which) and the SLK320 came comprehensively last by a huge margin because he couldn't seem to change gear - and when he did he got the wrong gear most of the time. In fact when he started the lap the car had virtually come to a stop before he managed to engage second gear. He and Penny Mallory both said that the gearbox was c!*p.

But the actual fact of the matter is that when it's got the right oil level and a few miles on the clock the change is very good. It's light and very short throw and you can snick between gears very quickly indeed. It's certainly no worse than a TT's or a Boxster's box. (I haven't driven a BMW). However, journalists review new cars as they come out of the box, as it were, so the reviews are going to be uniformly bad.      

(Edited by Tony at 12:39 pm on June 21, 2002)

 

[altreed]

SLK 200 Gearchange

I can comment on my wifes z3 2.8 (manual), their gearbox is a bit stiff and notchy.  The car has only done 12000 lightly driven miles, so it is still being 'run-in'.  With the knowledge that the oil level and oil type effects the quality of the change I will enquire when it goes in for a service.

I mentioned earlier that I had a manual 190e, it was not a good gearbox.  The rest of the car made up for it though

'97 c36 silver 68k