Post 96 5-speed auto g/box - premature failure?

[DaveT]

Anyone got any experience/opinion/comment on this? Someone on Benzsport has been talking to ZF about the 722.6 series gearbox and the excessive failure rate. ZF appear to say that failure rates between 60 and 100k miles may be lessened if the fluid is changed after 30k (- bearing in mind that MB state that these boxes are 'filled for life').
I wondered if Andy (or any else) has noticed 'excessive' (by Merc standards) failure rates.

I hope not.

DaveT   (1996 C250TD- 5-speed auto.....)

 

[Koolvin]

Post 96 5-speed auto g/box

only in manual's

 

[altreed]

Post 96 5-speed auto g/box

My '97 5sp auto just packed up (went mental) at 63k.

Cost an arm, a leg, both heels and kneecap!

 

[Andy]

Post 96 5-speed auto g/box

Hi

Well at least somebody is admitting there may be a problem. As far as I am concerned. There is a very high rate of failure with these boxes. I am not so sure that the technology was proved extensively as it should of before it went into production. Taking into account that these boxes are fitted to a number of other makes as MB have sold them to I think Jag & RR.

I  thought it was a little iffy when they said the oil stays in for life. I have never seen a vehicle which did not have adverse problems when oil was left in for life in any component.

Trouble is how do I compete. If I start replacing the gear box oil & filter and recommending it to my customers. But the dealers know nothing of it or they come out with the standard saying. The box needs no change of oil. Then its me that looks like I ripping of my customers. A catch 22. What to do?????

Regards

Andy @ www.mercedesservicing.com

 

[DaveT]

Post 96 5-speed auto g/box

Woo-Hoo! Only 3,000 miles left.
Well Andy, I might as well be the first to ask; How much for fluid and filter change?
I've emailed ZF in Germany for their thoughts- let's see if they come up with the same answer to the original question as to their recommendations on fluid life.

I hope this topic has not provoked too many unnecessary visits to the toilet. I must admit it has made me a touch queasy. Perhaps a little knowledge IS a dangerous thing??

Regards, dt.
60k and counting.....

 

[fuzzer]

Post 96 5-speed auto g/box

ohh interesting .. im currently sitting at 32k im wondering if i should change the oil .. what do you think andy ?

 

[Anonymous]

Post 96 5-speed auto g/box

I have changed my oil as I don't believe in lifetime fill in any gear / auto box.  Easy job. You need a dipstick, filter and 7.5 litres of fluid.
Mine came out dark but not burnt.  After all there are slipping clutches in there and a hydraulic valve body.  Normally the valve body starts playing up, probably due to silt and gum stuck in there.

 

[dave elcome]

Post 96 5-speed auto g/box

I have got to agree 100% with the "change it brigade", i simply can't get my head round oil lasting the life time of a component. I fully appreiciate that there are constant advancements in oil technology, but they haven't made it that good!! I will be changing mine over the next few weeks.

As an addition to this, during my time in the trade, we used to deal on a regular basis with a transmission specialist, i have never known them do a "bum" job, and would reccomend them readily to anyone. But when i was recently chatting to their autobox "Guru", he came out with the same thing, "don't change the oil, its filled for life". This will be the first time in nearly 30 yrs that i will be ignoring their advice.

 

[Andy]

Post 96 5-speed auto g/box

Hi All,

The jury is still out on box oil change. MB use to have the box oil changed every 36k.(Dave E your 300te should be changed at mutiples of this millage and don't forget the torque converter) As for the rest with electronic boxes. The main problems we have are the valve chests. But whether its caused by not changing the oil is another matter. It cant hurt to change the oil, but whether it will prevent other problems I can't say. But if its you picking up any bill then I think getting the odds in your favour is the order of the day. So box oil change has it.

Did I make sense? I am still checking on who else besides MB supplies the correct oil

Regards

Andy @ www.mercedesservicing.com

 

[dave elcome]

Post 96 5-speed auto g/box

In that case Andy, what oil do you use?

 

[Andy]

Post 96 5-speed auto g/box

For you box Dave the normal Dextron II is what required. The electronic boxes are the problem.

Regards

Andy @ www.mercedesservicing.com

 

[DaveT]

Post 96 5-speed auto g/box

I have received a reply from ZF, who inform me that Mercedes actually make the 5-speed box themselves ( I didn't know that).
 The ZF man (Peter Korbe) says that changing the oil in their filled for life boxes  'may extend the life...but you must use exactly the same as the original oil since Dexron will degrade too quickly.'
 He also stresses how important it is not to over/underfill, as this will cause more damage than the original oil would have done.
 So I suppose the big question is- Do we know what the original oil is?
 Perhaps the best answer is to just keep an eye on the condition of the oil and only consider changing it on the advice of an auto transmission specialist (or MB).

DaveT
(1996-C250TD)

 

[Anonymous]

Post 96 5-speed auto g/box

Ah Nuts.
This info may have come too late !
Last night my 96 C200 ( 5 speed Auto, 61K, pre-facelift. ) seemed to get itself confused and stuck in 5th.  I stopped as it didn't seem to be changing down, but it was still in 5th and trying to set off in 5th.  No reverse.  So I switched it off and on, and it was immediately perfect and hasn't missed a beat since.  - Was the computer confused? ( I was ) - Or is this a sign of the 'valves' Andy?.  As long as it breaks before the signature warranty runs out in June I'll be happy. Think I'll start taking bets on how long after the end of the warranty the gearbox lasts.  Is the gearbox oild change an easy DIY job? - and have we agreed on Dexron II or not?  Worried of Hartlepool....

 

[altreed]

Post 96 5-speed auto g/box

Stewart,  My gearbox fault just started to change badly, little kicks when it finally engaged.  Gradually it got worse, to the point that it would miss a gear, rev to the limiter and then 'bang' the wheels would start to spin.  

I gave the car to the garage to look at it, they hooked up their electronics and were getting crazy results off the computer, eventually it jammed into 2nd then 4th.  It was the electronic valve control unit that was at fault.  The unit costs £462 + Vat, plus labour.  However MB gave me £162 refund on the old unit.  I suspect they buy it back to evaluate the damage, retrospective.  Initially I thought they were being kind, but having read this thread, it looks like it might be market research!

Dave Altree
AMG c36

 

[Andy]

Post 96 5-speed auto g/box

Hi Stewart

You could pop into your local MB dealer. Get them to check the fault codes. They will probably do this FOC. See if the box has recorded any faults.

Regards

Andy@ www.mercedesservicing.com

 

[Anonymous]

Post 96 5-speed auto g/box

There appear to be two problems with the 722.6 box.  Problem one is the electronics suffer a glitch and stick in the last selected gear, even neutural.  Switch off count to five switch back on and all will be ok.
The other problem as we all know is the valve body.  Since changing the oil I am sure the shifts are smoother, and my car hasn't failed to engage properly at all except for one lazy reverse on a cold morning, and that could be linkage adjustment.
My suspicion is that the hydraulics are under less pressure, for efficiency, and so the valve body can stick more readily.
The oil is made by Sh*ll
and is Dexron IIE I believe.  Just buy MB fluid for safety as this is definately a MB box.  

 

[steveperry]

Post 96 5-speed auto g/box

My car is currently with MB to have the auto box "fixed".
The symptoms were very subtle though... If driving without
using the kickdown there was no noticable problem at all. However, if I accelerated hard (with kickdown) the gearbox would "hesitate" when changing from 2nd to 3rd (or 3rd to 4th I'm not sure) and then "bang" into gear.  

Fortunately the car is being repaired under a Signature warranty. My only gripe is that they've had the car for a week and are awaiting parts (some kind of sensor?) to arrive from Germany. I've been abroad on business for a week so thought this would be the ideal opportunity to get the car fixed but I got back yesterday to find they still have the car

Oh well, at least I have a K reg E220 as a courtessy car until I get my baby back.

My old 190E never had a problem with it's 4 speed mechanical auto box. I hope now that MB have looked at the auto box on my car that it doesn't play up in the future.  One of my first posts to this forum was how the autobox dipstick cap on new cars are "locked or sealed" when compared to older MB models.

*Edit* by the way... my car has done 56k miles.

S. (still awaiting my car back)

(Edited by steveperry at 9:32 pm on Mar. 5, 2002)

 

[R10RGT]

Post 96 5-speed auto g/box

I have the 5 Speed Auto box in my 1998 C 200 Sport - 96k miles and no worries?!! (To be fair, the first 88k miles were motorway miles...).

Am I correct to assume that it is the same 'box in the 230SLK? - I notice the gate is completely different, so it is not obvious?!!

 

[Anonymous]

Post 96 5-speed auto g/box

Yes it is the same box.
All the electronic boxes are the same type but newer versions have the Tip selector.  The older type must have been too complicated for some people I guess.  P R N D seems to work ok for me though.

PS my box has been smooth as silk since the oil change, and I have heard of an old style 4 speed with a stuck valve body when the oil wasn't changed.  Food for thought.

(Edited by Dieselman at 10:37 pm on April 22, 2002)