Main screw from rear differential left loose after main dealer replaced subframe. Clunking gear changes.

[E250_MK]

I took my 2012 E250 into a main dealership for a service, and they broke the news that the subframe had corroded and needs repalcing. They replaced the subframe for free under goodwill, due to Mercedes acknowledging a manufacturing fault.

When I collected it, I noticed that the geart changes seemed a bit rough sometimes, and at times a definite CLUNK is felt and heard. For a few days I was convinced that there was a can of coke or something rolling around in the back hitting the sides when I accelerated or braked.

Eight weeks later I realised something must be wrong and took it back to a main dealer. They carried out an inspection and found the main screw from the rear differential was loose, and that it must have been forgotten to be tightened when the subframe was replaced. They tightened the screw, and everything is smooth now.

I am annoyed something so basic was forgotten by a main dealer. I am also worried that the screw being loose will have caused unneccessary wear and tear, or other damage.

Does anyone know what wear and tear, or other damage to the differential and/or other parts might have been caused by the main differential screw being left loose?

 

[grahamcol]

Welcome.
Well l guess you should have taken it back straightaway. However all seems well now and l don't think I'd worry unduly. I think what's probably happened is that the attachment bolts of the diff to the subframe were left loose rather than a "main screw" whatever that is.
Chill and enjoy the car would be my advice.

 

[E250_MK]

Thanks for the reply. Makes me quite anxious not being able to trust the work of a main dealship. What else have they missed? Do I need to get the whole subframe reinspacted? Very poor service indeed.

 

[grahamcol]

Thanks for the reply. Makes me quite anxious not being able to trust the work of a main dealship. What else have they missed? Do I need to get the whole subframe reinspacted? Very poor service indeed.

For non warranty work it's always best to go to a decent independent Mercedes specialist. That's what most of us on here do, other than diy. They are usually a lot cheaper and more knowledgeable with older cars. My Merc indie used to have the main dealer cars sent in when the official dealer couldn't sort them!

 

[E250_MK]

Very good to know! I hear Autoclass in Milton Keynes is pretty good.

 

[Steve@Avantgarde]

I doubt very much any damage has been done to your vehicle.

Incidentally my father had his subframe replaced at a MB dealer just recently. I handled it all for him just to make sure they didn't try to pull the wool.

I picked it up and it drove terribly on the way home, knocking from the OSR and crabbing up the road.

Anyway, straight to my workshop and I found that they hadn't seated the airspring properly, it was resting on the chassis edge rather than in the recess and as a result the whole cars wheel alignment was misaligned. After I sorted it it was fine but it does make you wonder how things are checked and tested.

Worrying thing is I used to work at that dealer too.

 

[E250_MK]

Yikes, not good at all. Great that you noticed it and got it sorted. That's sorta what I'm afraid of - what else have they messed up, but I don't know what to check for?

 

[Steve@Avantgarde]

Yikes, not good at all. Great that you noticed it and got it sorted. That's sorta what I'm afraid of - what else have they messed up, but I don't know what to check for?

Perhaps have a trusted independent look over it, just to give some reassurance if nothing else?

 

[E250_MK]

I took the car into Autoclass in Milton Keynes. They assured me that there would have been no other problems caused by the main screw being loose. Very good to know.

 

[weds]

I took the car into Autoclass in Milton Keynes. They assured me that there would have been no other problems caused by the main screw being loose. Very good to know.

But they would say that..

 

[E250_MK]

But they would say that..

I should point out that it was NOT Autoclass that made the initial mistake, so Autoclass would have no reason to cover up any knock-on problems.