hunting gearbox c200k

[richyrrr]

Hi i have had a look at a friends c200k 2004 yr car - the problem it has is that as you drive on partial throttle at about 30mph and ease off the power then reapply it jumps quite suddenly down the box and back up again. my friend has replaced his gearbox oil and filter ( all gen merc ) but it has made no difference also it is slightly worse from cold. I have put it on an autodiagnostic and snap on modis code readers and no codes are present. any help would be greatly appreciated.

 

[television]

This car will hold onto the lower gears to warm up the CAT, so that could account for it when cold, but not when hot.

Other than that its a new one on me.

Welcome to the forum

 

[MB TECH WARRINGTON]

Possible gearbox contaminated with coolant. get this checked out.

 

[richyrrr]

we have just changed the gearbox oil and kept what came out we didn't find any coolant in it , it looked good and did not smell burnt

 

[television]

we have just changed the gearbox oil and kept what came out we didn't find any coolant in it , it looked good and did not smell burnt

Any coolant should not apply to that car as 99% of those faults finished 09-03 and caused a humming sound and viabration at around 2k revs when pulling lightly.

It is an odd fault

 

[richyrrr]

more info from freind - now says it only happens from cold and goes when hot

 

[television]

more info from freind - now says it only happens from cold and goes when hot

Then it is the normal lock up that I said in the my first post, they are much better in the slightly warmer weather

 

[richyrrr]

Do you think therefore that a sensor could be overcompensating . As I have now driven it and it doesn't feel like others I have driven its all over the place until hot

 

[television]

Do you think therefore that a sensor could be overcompensating . As I have now driven it and it doesn't feel like others I have driven its all over the place until hot

That is not right then, and not something that has come up before, unless is this car fitted with the 7G box and not the 772.6 box.
Do you know what box is in the car

 

[MB TECH WARRINGTON]

Any coolant should not apply to that car as 99% of those faults finished 09-03 and caused a humming sound and viabration at around 2k revs when pulling lightly.

It is an odd fault

have you ever driven a car with glycol contamination?

and having worked on many glycol contaminated cars i can tell you that many have had newer registration than 2003.

 

[MB TECH WARRINGTON]

we have just changed the gearbox oil and kept what came out we didn't find any coolant in it , it looked good and did not smell burnt

did you just visually inspect or get it analysed? better to be safe than sorry, send us a sample i will be happy to do a glycol test on your oil.