W208 98 CLK gear box problem

[Linux_cat]

Afternoon I was wondering if anyone can help.

I have had a clk 320 for over a year now, i bought it on around 80,000 miles and its a 98 plate, it had full service history up to this point i have taken it to a specialist since.

Im not a fast driver, in fact i hardly put my foot down but my friend drove me car back on the motorway the other day and noticed that the gear box was slippin at around 125pmh, it reaches this speed and its like the engine looses all power and drops down to 80 mph, at this point the engine starts responding to the accelerator pedal gain.

Im wondering if changing the gear oil fluid will sort this problem out, i did mention i felt there was something wrong with my gear box when i took it to a specialists they ran some diagnostics and it got the all clear, so im baffled any suggestions?

 

[Linux_cat]

Also...can i change the gear fluid myself? are their any tutorials on the internet you could refer me too?

 

[Mr Teddy Bear]

You can change it yourself, if you have access to a garage with doors. You need a wind free dust free environment. The parts come to £70 approx so if an independant will quote you £120 ish I'd go with that, the sump needs to come off depending on whats found in there will govern what happens next.
No point refilling a duff box.
There is an extensive thread under DIY wont tell you how to diagnose, strip,repair and rebuild it though. Use Merc Transmission Fluid its supposed to be fully synthetic. I wouldn't take a chance on anything else. I bought the joint/filter from a reputable factor forgot the name identical to the bits from merc,.
Hope this helps.

 

[corradoman]

I wouldn`t be saying 125mph on a public forum if i was you mate, Lots of people have been investigated into for speeds like that and been convicted! Are you sure its not the rev limiter kicking in, Good luck with sorting it mate

 

[Mr Teddy Bear]

It doesn't sound like the speed limitor, more like slipping clutch plates!

 

[MB TECH WARRINGTON]

Afternoon I was wondering if anyone can help.

I have had a clk 320 for over a year now, i bought it on around 80,000 miles and its a 98 plate, it had full service history up to this point i have taken it to a specialist since.

Im not a fast driver, in fact i hardly put my foot down but my friend drove me car back on the motorway the other day and noticed that the gear box was slippin at around 125pmh, it reaches this speed and its like the engine looses all power and drops down to 80 mph, at this point the engine starts responding to the accelerator pedal gain.

Im wondering if changing the gear oil fluid will sort this problem out, i did mention i felt there was something wrong with my gear box when i took it to a specialists they ran some diagnostics and it got the all clear, so im baffled any suggestions?

you say the engine loses power, sounds more like an electrical problem, prob more to do with engine than slipping box,m

if it was a slipping box the car would just rev to redline with no drive transmitted

 

[Linux_cat]

ME TECH, if it was an electrical problem the Merc specialist would of picked that up right, apparantly he connected up to some sort of computer....

if it is the clutch plates slippin, then will changing the gear fluid sort it out?

Thanks for the help its greatly appreciated.

 

[Mr Teddy Bear]

No it wont, If you suspect a transmission problem I would get it looked at sooner rather than later.....before the bearings are damaged by contaminated oil.

 

[television]

I do not think that it is the box at fault, could be the MAF failing

 

[bigasotonuk]

Hi,
If you have no record of the gearbox fluid & filter ever being changed, I would do it, but regarding your problem I have to agree with Malc regarding the MAF but it seems strange that you have no other symptons normally associated with MAF failure.

 

[television]

I wonder if this could also be a speed sensor thing at that speed