W211, E320 CDI, 2007 Plate, 7G speed gearbox noise

[Sebs007]

Hey everyone!

I’m new here and hoping to get some advice.

I’ve been searching around but haven’t found anything quite like the issue/noise I’m experiencing with my car, so I thought I’d reach out to see if anyone can help me figure this out!

I’ve had my E320 07 plate sport sedan for about a year now, and I believe the gearbox code is 722.9. Recently, I’ve noticed a strange metallic noise coming from what seems to be the torque converter area.

Here’s what’s happening:

• When I start the engine cold, the noise is barely noticeable.
• It gets quieter when I put the car in drive when the engine is cold.
• Once the engine is warm, the noise becomes louder in neutral or park.
• I’ve changed the gearbox oil and filter following manufacture specs but that didn’t seem to fix anything.
• The car shifts fine when warm, I've only noticed when the car is cold and downshifting from 2nd to 1st, it feels a bit rough (no clunking though)

The gearbox itself seems to be working fine overall, but this noise is making me a little worried. Has anyone experienced something like this or have any suggestions on what could be going on?

I’ve also attached a sound clip of the car in neutral, switching to drive, and then back again, if that helps.

Thanks a lot in advance for any advice!

 

[abecketts]

Check the engine mounts and gearbox mount, they might be old and that could cause the noise, it’s how I fixed my w211 e280

 

[MrGreedy]

On my 2011 E350CDI with 7G box, it also is a bit rough going from 2nd to 1st when cold. Changing engine mounts and transmission mount, if anything, has exacerbated that particular trait. But every other shifting characteristic has got smoother and quieter since the mounts change.

 

[Sebs007]

Thanks for advice, engine mounts are on my to-do list as well as I’m getting this weird droning sound when turning left at speed. I’ll get this changed and report back!

 

[SpikyMikey]

On my 2011 E350CDI with 7G box, it also is a bit rough going from 2nd to 1st when cold. Changing engine mounts and transmission mount, if anything, has exacerbated that particular trait. But every other shifting characteristic has got smoother and quieter since the mounts change.

Likewise my 2013 C Class was a bit clunky when cold coming up to junctions or roundabouts. Smooth enough when warmed up though.
Interestingly the roughness in the low gear change pretty much disappeared if sport mode was selected before setting off.

 

[markjay]

Likewise my 2013 C Class was a bit clunky when cold coming up to junctions or roundabouts. Smooth enough when warmed up though.
Interestingly the roughness in the low gear change pretty much disappeared if sport mode was selected before setting off.

Same here, my 2013 W204 had clucky upshift when cold, it's a known characteristic. Had the ATF changed and the TCU software updated etc.

That been said, 2013 cars will have the later G7+ variant, so not sure if the OP's earlier 7G is affected.

 

[MrGreedy]

Same here, my 2013 W204 had clucky upshift when cold, it's a known characteristic. Had the ATF changed and the TCU software updated etc.

That been said, 2013 cars will have the later G7+ variant, so not sure if the OP's earlier 7G is affected.

Yeah, mine is actually a 7G+, but in a short window where start stop wasn't/hadn't yet been introduced. Such a shame!

 

[slade1]

Engine/gearbox mounts? My 05 CLK (272) still has all original at 92K miles and is super smooooooth.
New eclectro plate fitted years ago.
When was the last oil/filter service?

 

[MrGreedy]

When was the last oil/filter service?

Op says in original post that changing the ATF fluid and filter hasn't improved the situation.
They didn't specify a date of that change, but seeing as they did it trying to troubleshoot the issue, my assumption is that it has been done on the very recent end of the gearbox oil and filter service interval.

However, Op, is it possible that the fill level is incorrect? Not a criticism, just trying to chase down the easy, cheap fixes first.

 

[Sebs007]

No worries, none taken It took about 7L without draining torque converter. I got it changed April this year