Transmission changes from cold

[jeremytaylor]

My 05 E320 CDI has recently taken to holding onto the gears a bit more than normal when cold - likes to go up to 3,000 revs before changing. Does anyone know what might be the cause of this?

It's an 05 with 62,000 on the clock. I'me the secind owner. Despite having being serviced by the same dealer from new, I noticed when I bought it at 52,000 miles that the tranny fluid hadn't been changed, so I got it changed! I don't think this would be the cause?

 

[BlackC55]

Are the changes smooth when cold?

You may have some fault codes logged and it may be worth plugging it in.

 

[jeremytaylor]

They are not as smooth as when warm. What sort of faults might there be showing?

 

[Dieselman]

If it's only done this since the ATF change maybe it's a bit short on fluid, also the MAF will cause higher revving due to the engine producing less torque.

 

[BlackC55]

You may also have a leak?

Pop in if you want and I will check it FOC and see if there are any leaks.

 

[BTB 500]

The handbook for my SL says the gearbox will hold lower gears for longer when cold (to help the engine warm up faster).

 

[jeremytaylor]

You may also have a leak?

Pop in if you want and I will check it FOC and see if there are any leaks.

Thanks, that's a very kind offer.

I haven't noticed any stains on the drive, but then these damned covers under the engine are good at disguising leaks!

 

[jeremytaylor]

Right, had the codes read a couple of weeks back and it came up with something like 'power surge to the gearbox valves'. The tech thought this might be related to a new battery that I had fitted (by them), and so he cleared the code to see how it goes. They said no fluid leaks.

Still the same, and Wednesday morning it was much worse - almost kangarooing and sticking at 2,750 rpm. Dropped it off for them to try from cold this morning, but haven't heard anything yet.

Thank goodness for warranties!

 

[jeremytaylor]

SO I rung the garage at 5.00 this afternoon as I hadn't heard from them.

"We haven't got your car, sir" said the receptionist.

"Er, you have - I left it there yesterday."

"I'll have to get someone to call you back."

The car was not looked at. Good to see that Mercedes have improved their service so much these days!

 

[jeremytaylor]

So they looked at my car today .

No fault codes showing but they accepted that my problem did exist (which was a relief!). They dropped the sump to check the filter - OK - and no other problems apparent. They thought there might have been an ECU problem, but there were no fault codes showing, so they reset the gear change parameters on the box, which seems to have done the trick, apparently. I'm picking her up tomorrow.

Took 5 hours labour apparently, but because they mucked up yesterday only charged me 2 hours, and reduced the charge by 20% (instead of the usual 15%), without any prompting from me, which I think is very fair.

 

[jeremytaylor]

Picked the car up this morning and the changes are much, much better - there's now no difference in the way it drives between cold and warm. Hopefully this will have cured it! Will keep you updated.