Hi,
I have joined this site in the hope that you guys out there may be ableto offer some advice?

I have been experiencing problems with my 1998 SLK for the last 2 months - the sequence of events are:-

[ol][*]Auto change of gears problematic[*]Garage ran diagnostics, car was in limp mode anderror was faulty break switch which was repaired (if problem persisted then new break switch would be required)[*]Car came back and after 2 days went back to garage with existing problems[*]garage ran diagnostics and said that solenoids needed replacing. When they dropped the gear box to start this work, they found further problems and then said that the gear box needed a re-condition. At the same time they also replaced the faulty break switch[*]Car came back a week later and STILL had same problems[*]So back to the garage it went again - car was plugged into diagnostics over a period of 5 days, no errors were reported. So they dropped the gear box and checked all of the work on the gear box recondition work[*]Car came back again another week later[*]Has been ok for about 6 days.Took it up to London at the weekend and it was fine in the city with all the stopping and starting[*]This morning I got in it to come to work (it had not been driven for 2 days) and here we go again:-[*]I applied gentle pressure to the gas and at 20 mph it was up to 4,000 revs, straining in 1st and would not change in to 2nd[*]Eventually it did kick in and all seems to be ok now[*]But this is the same problem I have been experiencing from dat 1. It seems to happen first thing in the morning. Struggles in 1st for a few minutes, then once it kicks up to second, it then seems to be ok[/ol]

Obviously I will be sending it back to the garage again (the recondition cost me a lot of money), but I am at my wits end. When it is plugged into diagnostics no error is reported and it is so intermitant that I am begining to think that I am imagining it - but in reality I know that I am not.

Is there anyone out there who has had a similar experience or anyone who can offer any words of advice or guidance???

Maybe I should look at putting it up fro sale and getting rid??? But this really would be a last option as I love my little SLK and do not want to go this route

yours hopefully - SLK1998

 

HI there, do you know if any fault codes were stored in the transmission CM or engine CM?
If the gear box has an electrical fault it will not change out of first gear and when moving the stick from P-R-N-D you feel a VERY harsh engagement of gear. If the transmission has a mechanical fault it normally stays in 3rd gear(limp mode) until the engine is restarted. It may also be engine related......as the transmission communicates with the engine via an electronic network a fault in the engine can prevent the transmission from up shifting, if engine torque is too low the up shift is delayed(faulty air mass sensors...incorrect throttle cable adjustment etc).I think we need some more info on this fault & fault codes
Hope this helps some Lozza

 

1998 but what mileage? 100k+?

You state NO TRANS CODES have been set. I assume this is also the case for the ENGINE since the two work in tandem.

If no codes have been set on your car I too have experienced / observed the same or similar problem to which you refer, but I do not know the cause.

IMHO I believe that the problem MAY be due to a sticky valve in the hydraulic valve block since 99.99% of the time it gives no problem. However every now and then, especially on a cold start I seem to get 1. A reluctance to transmit drive thru the trans (a bit like being in neutral or imadequate fluid in the Torque converter but with some (lets say 25%) drive remaining. 2. a reluctance to move out of 1st gear into 2nd.

However once the initial change from 1st to 2nd has been made after 100 yds or so the problem disappears and doesn't reappear for many thousands of miles.

A trans oil changed appeared to improve matters but I'm not convinced that the problem has been totally eradicated since it has occurred once since the trans oil change.

I'm certainly NOT going to let anybody loose on recon the box since the problem is so intermittent /infrequent it would not be worth the cost and may introduce all sorts of new problems. i respect MB reliability. It has never occurred when the trans / engine is warm.

Let us know if you find anything out.

Good hunting,

Stuart.

 

I had a 99 SLK and the problem was it would slip in first but all the other gears were fine. you could drive it fine all day as long as you were in W mode. When it was in drive it would slip gears but if you manually shifted the shifter from 1st up threw the gears to drive the car would be ok. the repair was the shift module or the PRND display on the shifer its an electronic module that tells the trans what gear its in. if you take it to a Benz shop they can look at all the values of the shifter when you move threw the gears and it will display an F when it doesnt recognize the gear. i would reccommend going to a dealer that way your not rebuilding a trans and it still not fix the car, granted it does happen at the dealerships too but they have the equipment to better diagnose the problem rather than guess.

 

I agree. with Chassis221..get it check with someone who has an SDS (Star Diagnosis)., and check actual values and their adaptation data. I agree also with (Snanceki), but I would STRONGLY RECOMMEND Transmission Flush, and not just "drain and fill"...it's cheaper and it's worth investing. I believe in BG Transmission Service and the additives they use for their Transmissions. IT WORKS GREAT!!! (Fully Synthetic Transmission fluid only on that car!!!).

take care
-mar-

 

Chassis and MasterBenz.

With your experience can you add anything further re this strange "lack of drive" reluctance to change out of 1st issue.

I'm aware that the engine ECU sometimes inhibits up change in order to assists the cats in lighting up but its the partial drive thing that most intrigues me.

I don't believe it is anything to do with the elctronics since gear change is faultless in all modes and it is so infrequent / inconsistent with the only relationship appearing to be standing for a period (a few days) and cold start (normal 0 - 12C ambient). An ignition off/on doesn't resolve the issue which only last for maybe 20 yds from start. It appears to be distance rather than time associated. I just let the vehicle slowly move forward slowly keeping the slip to a minimum (i.e. not using extra revs) and it then clears itself.

This has occurred on both my M112 engines SLK and S Class.

You strongly recommend trans flush. How does this work? An external power flush device that forces "clean" oil through the system which is more likely to flush out any microscopic debris? At 100k my oil pans were spotless with no debris whats so ever...at least that I could see!

Any ideas on what is special about MB trans fluid...other than it costs a lot! what do you use in your shop?

stuart

 

Sorry, it's taking me awhile to reply, but I've been extremely busy. Transmission flush is great!!! I do all the time, and I recommend to use BG Transmission Product (Universal Fully Synthetic Transmission Fluid), as well as their additives (e.g. Cleaner and Soft Shift Formula). Transmission Flush is basically like a dialysis...it hooks up inline with your transmission and it removes the old fluid and exchanges it with new fluids (BG Product). Usually, I use 16 quarts, and it helps out and it's a great preventative maintenance. Also, make sure you replace you Transmission filter as well.

take care,
-mar-

 

Thanks for the reply.

Stuart.

 

BG Products (Universal Fully Sythetic Transmission Fluid) is compatible with MB Transmission fluid, and it's a lot cheaper. That's ALL we use at the dealership, and that's what I use in my shop now.

take care Stuart,
-mar-

 

masterbenz check out my post ,,,battery ran down,,now i have hars engagment but i can back up hitting the breaks,,kill the car,,and then its fine the rest of the day till it sits for several hours