[Kev124]

Most A Class owners on this forum are aware of the dreaded auto transmission problems and the poorly designed 1st gear drum that cracks (usually around the 70km mark).

I know that there is a redesigned replacement drum now available which apparently cures the problem.

Does anybody know if this modified drum actually was used in the later models of the WDB168's or is it something that emerged after the WDB168's were phased out?

Does any body know the new part number of the replacement parts.

 

[keyhole]

I don't have an answer to your question from scanning my WIS, however I did note that all W168 auto transmissions are type 722.7XX, and all W169 auto transmissions are type 722.8XX.

 

[forrera]

breaking forward gear drum cannot be eliminated but can be avoided, because if you strengthen it, the gear drive underneath it will break, I've seen many of them broken.

 

[Kev124]

breaking forward gear drum cannot be eliminated but can be avoided, because if you strengthen it, the gear drive underneath it will break, I've seen many of them broken.

A mechanic friend of mine has done a couple of A class auto gearboes including one this week. He sourced an updated drum which has the circlip in a slghtly different place making the drum stronger and less likely to crack.

 

[Kev124]

Tks Keyhole...perhaps the later gearbox is the source for the part.....
By the way....is the 722.8xx box capable of being installed as a replacement for the 722.7xx box?

 

[keyhole]

By the way....is the 722.8xx box capable of being installed as a replacement for the 722.7xx box?

That I don't know....

 

[forrera]

just got a new first gear clutch hub delivered the other day, this time it looks a bit different. BM are aware of the problem, I hope this is the answer. if interested I can upload pictures of new and old hubs

 

[forrera]

pictures of old and modified 1st clutch hub. they carry the same part number

 

[Kev124]

Tks Forrera

Do you know if the modified clutch ever made it into production W168's......I've noticed that some A class seem to avoid the gearbox issue alltogether. So makes me wonder if the later models had the modified ones installed.

Do you know if the the W169 gearboxes can be used as a replacement for the W168's.

 

[forrera]

sorry, I don't know much about w169, yet, LOL.
these hubs also crack round the bend and not only by the circlip, I've done one today and the complaint was "first gear slipping slightly". At first, the hub looked intact, but when I used special magnifier then I saw a very thin crack that would open like a sandwich under pressure.
the modified hub looks stronger where the circlip goes, not by the bend which makes this late modification a total waste of time.
picture to follow.

 

[Kev124]

Tks Forrera.

Strange that Mercedes Benz could under-engineer something so poorly on a a car model that is comparatively popular and sold in high numbers. Benz gearboxes are generally speaking very robust items. Although Benz quality control suffered a fair bit during the early 2000's.

A mechanic friend of mine suggest that the problem is caused by excessive stop-start traffic, what do you think?

 

[forrera]

pictures of damaged drums, an early design starting to break near the circlip and the other one is an early modified drum which startd to crack from a different place.

 

[forrera]

and yes, gentle driving and regular maintenance will make it last longer.

 

[forrera]

I believe this modified drum is less than a year old, came out of a gearbox I'm woking on today. no comment

 

[Kev124]

This is BAD NEWS indeed. My understanding is that Benz modified the circlip by moving it further down the drum in an attempt to make it more robust. It seems from your example Forrera .....not to have worked.

I also note from a couple of your photos that some drums have a wedge in the valley of the splines on the outside of the drum...is this part of the mod or is it something additional.

 

[forrera]

not sure about the wedge in the valley of the splines . any how, despite all the problems with these gearboxes have and high mileage they are capble of, we still expect them to go for a lot more miles. I've got 2 a170 autos, one 141k miles and the other 132k and still going strong.

 

[Kev124]

I wish you years of problem free motoring.......The A170 only appears in the W169 A class here in Australia. Aussie's only saw the 140, 160 & 160L and the 190 & 190L's were on offer....no diesels either. I did however see one Vaneo here that had been imported.

 

[old bloke]

Hi guys.
i wish i'd found this site 5 weeks ago, i bought my son a 2002 A 140 auto and within no time i got the gearbox F on the dash ( private sale). I decided to do things properly and went to merc for diagnostics, they told me the ecu was at fault and also the gear selector. I purchase a second hand selector as i thought merc prices a little high tbh and let them fit it which cleared 1 code. Then i came across this site and lofty's also and decided to go for a second opinion at a motor engineering company that is local. They have dismissed mercs diagnosis, got the F to go away for now and told me that the forward clutch drum needs replacing, ( if you floor it to pull away F comes up, all other gears are fine)
Does anyone ( looking at Forrera ) know where i can purchase one as to keep costs down i'm doing the donkey work myself and letting the experts change the parts.
cheers

 

[forrera]

no problem old bloke, this is what I do all day long. the k1 clutch hub is a little under £200 from the dealer and they are always in back order, but I have to advise you, this is not a diy job. I'm happy to help, my garage is in west London

 

[old bloke]

Cheers Forrera. I'm not changing the hub myself, just stripping box out and putting back in to keep costs down. I would've been straight round to you if your garage was closer, but i'm in somerset. I was surprised tho, at how badly wrong Merc got the diagnosis, might try to get some money back. You don't sell boxes with the new hub in do you? just a thought.

Just thought, do mercedes do an electronic parts catalogue for number or just asking for drum is sufficient?