[W208] Unstable auto gearbox?

[nodger]

I recently had my CLK230 serviced and the mechanic said he replaced the transmission oil. It was OK for the first week or so, but since then I've noticed a few issues:

1. After a cold start, the engine seems to need to rev significantly higher before changing from 1st to 2nd gear
2. Even when the car is warmed up, the gearbox sometimes downshifts at fairly inopportune moments (e.g. on roundabouts/corners)
3. At one point yesterday morning, it refused to go above 3rd gear regardless of how high the revs went. When I stopped at traffic lights, I popped it back to P, then D again and everything appeared OK.
4. It seems to take longer to shift from D to R now, and it doesn't feel like it's holding as steadily when in D on an incline.

I've had MAF troubles before, but I don't think that would explain some of the issues above. Do I need to get him to take a look at the gearbox, or does it just take a while for new oil to 'bed in'?

Thanks.

 

[television]

Do you know if the mechanic used MB fluid

 

[nodger]

Do you know if the mechanic used MB fluid

Yes, he said he ordered it from the local MB Dealer. He pointed to the empty bottles when he was telling me about it, but not knowing much about it, I didn't really question him further.

 

[sweeper]

i had a problem with poor gear changes after changing the oil in mine, 1-2 when cold was very poor, often changing witha clunk, i also felt a clunk when coming to a holt, i put it down to having battery disconnected and the box losing it's adaptation values and having to relearn them, this was just a guess, but the box settled down after a couple of months and is still fine now some 30000 miles later (162000 in total) being stuck in 3rd gear never occurred on mine though, i suggest checking gearbox oil level and maybe checking the seal on the filter (assuming it was changed).

 

[BlackC55]

I suspect the level is incorrect.

How much atf did he use?

 

[nodger]

I suspect the level is incorrect.

How much atf did he use?

I'm not 100% sure, but I think he said about 7 litres. Unfortunately, he's off on a weeks holidays, so I can't query it until next Monday/Tuesday. I guess I can see if things improve between now and then.

On a related note, what's the recommendation for 're-learning' when the battery has been disconnected for an extended period? Is it best to take the car out for some motorway driving, or would it be more realistic to drive around town for a while?

Thanks to all for your replies.

 

[BlackC55]

Just drive it normally. It will adapt to your driving style.

 

[television]

Just drive it normally. It will adapt to your driving style.

The above is worded perfectly, there isnt any more to it

 

[nodger]

The above is worded perfectly, there isnt any more to it

Just came across this procedure:

http://mbclub.co.uk/forums/showthread.php?t=19457

It seems that it's made a difference to a lot of other member's gearchanging.

[Did this myself and it's definitely made a huge difference. My 1st-to-2nd gearchange is still a little jumpier, but
acceleration up through the gears feels a lot more... linear than it used to]

 

[Alps]

as said by BlackC55, check the level, i had the same problem after replacing the gearbox on mine, in the end we found it was almost 3/4 of a litre short! been ok since!

 

[nodger]

3. At one point yesterday morning, it refused to go above 3rd gear regardless of how high the revs went. When I stopped at traffic lights, I popped it back to P, then D again and everything appeared OK.

It happened again last night when I had just joined a motorway. Got stuck in what I think was 3rd gear, doing about 50mph at 3700RPM. This time I had the radio off and noticed that there's also a rasping, whistling sound that changes pitch in sync with the revs. From what I've read here, that suggests that there's a problem with the torque converter or pump. At this stage, I assume it'd be best if I didn't drive it any more? Could this have been caused by underfilling the ATF?

[edit] Nice intro to the torque converter, for those of us who have never seen one

http://en.wikipedia.org/wiki/Torque_converter
http://auto.howstuffworks.com/torque-converter.htm