2011 WK2 CRD Trans Issue - W5A580

[Roche]

Hi All

Trying to establish and find a repairer that may be able to help sort out a thud / clunk coming in between gears(typically in 1st).

I have found until the trans temp reaches 50 degrees, nothing is heard or felt. But as soon as the temp reaches above this, a gentle take off from the lights, I can hear and fell like thuds in First gear. Something 2 or 3 until it shifts into 2nd.

If I use the manual shifter, shifting between gears is smooth.

Would anyone have the same issues, and would anyone now how to resolve the issues, or point me in the right direction.

Many thanks.

[GMEMUD]

I'd be looking at the basics first, like has a service been done on it recently? if yes, what oil was used? How many Ks has it done since last service? was the filter changed? If it nearly due for a service I would get it done now with new oil and filter to see if there is any change.
Regards Ross

[yoda42]

There was a TSB for a software flash for atuotrans to solve the thump

[Roche]

Hi,

I did have that TSB applied but it soon came back and even after immediately after the TSB, it was still there.

A transmission service has been performed at 85,000 Kms. I was hoping this would help, but it hasn't. As for what oil was used, I'm not sure to be honest but the filter was changed.

[Clarky]

The W5A580 (NAG1/722.6) merc box has a conductor plate with solenoids on it that control the shifting, it is possible that you have a bad connection on the conductor plate or a dodgy solenoid.

When they serviced your transmission did they flush the old fluid out or just change the filter? If only a pan drop & filter change then 2/3 of the old fluid would still be in the G/Box. It would be worth changing all the fluid.

Look for a transmission specialist with Mercedes experience or try a Mercedes dealer, they should know these box's well.

[Roche]

Hi Clarky

Thanks for the information.. Would you think they if it were a conductor or valve body that the noise / thump would be consistent even when just starting off for the day and vehicle is cold??

If I look at my temp display it only ever happens after the cars tran temp reaches above 50, last couple of days I have been observing it is 55.

Also, I have a diag tool for OBD and it is picking up no DTC..

I'm just wondering if it could be the Transfer Case and whether it would be good to change the fluid in it also.

Thanks

[Clarky]

50°C is only just getting warm, my normal running temp is 65° to 70°C.

I would change the auto fluid again, making sure the right stuff is used.

Another thought If they over filled the transmission as the fluid as it gets hotter it expands causing the fluid to aerate.
Read pdf below
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