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W129 500SL Auto Box Slipping

ian11

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Joined
May 1, 2010
Messages
48
I had clutch slip on my morning run yesterday. As soon as it was clear what was happening I limped to a safe space (5 min journey) and the car is rested up.

We just had some local flooding, I'm not sure how high it got but I suspect it was enough to touch the underside of the car, not a great deal more.

The AT was fine up to and including a 60k mile service 4 weeks ago. The issues began immediately after the flooding a couple of days ago. The Merc dealer paperwork doesnt give the work package in detail unfortunately.

After reading AT slippage elsewhere on this forum, my fingers are crossed that this will be solved with a flush & filter.

Does anyone have any thoughts or advice? I don't have the owners manual so I'm trying to track down a way to check the levels before I commit to a breakdown truck to the dealer.

I have a spare car so I can afford to let it rest and dry out in the (45C) sun for the time being. Of course the flooding could be a coincidence..!
 
Hi Jay,

I'll be going back to the car later (its some way away) I was hoping to hear suggestions first. I've never dipped an AT before; I assume same basic procedure as oil?

Is Merc AT fluid special or can it be bought over the counter?
 
Hi Ian..

You will need to get the car up to temperature.. i sugguest drive it around for a while. After car has been running at full temp for 5-10 minutes, dip the transmission oil, just like engine oil. Should be up to 80 degree mark.

ATF dexron 3 is fine for your car, if you do need to top it up, you will need to add a bit at a time through the dipstick tube. You will need to wait a while to re dip as it takes a while to settle at the bottom.
 
Thanks Jay,

I didn't know where to start without the manual and it's one of those things you can get wrong

Seems it was nothign to do with water, level was VERY low, took a litre of juice to get it to the correct level, 'box seems fine now

Now the real question comes:

The car was serviced by MB 3 weeks ago...why the <beep> didn't they check the AT fluid level????? It's not leaking in any visible quantity and so the level must have been dire at the service!

This caused a breakdown and may have done internal damage to the gearbox.....yet more dealer woes....asking them for the service documents now (and being held off with a big stick)
 
Check your invoice for a transmission filter or auto-trans fluid to see if it was changed--or not? For a while after the newer auto transmission fluids were introduced Mercedes regarded their gearboxes as "sealed for life" but they appear to have reversed that policy now. It may well be it was not scheduled for a change on the service sheet but the level should have been checked. If your car has the older 4 speed hydraulic box it required a fluid + filter change every 36,000 miles.
 
Thanks - that's really useful to know as I "go into bat" with the dealer. The invoice is very vague "100,000km service" only.

So frightening to think an MB gearbox could be trashed by £3 worth of AT fluid....a real reminder of the old chestnut 'check your fluids regularly'!
 
Have a read of these PDF's R129 Service Sheet and M-B Factory Approved Service Products - Benzworld.org - Mercedes-Benz Discussion Forum You may have to join that forum to read them ?
Ask to see the job sheet for your car- there should be one -otherwise how could they calculate the cost of your invoice??? If you don't get a satisfactory answer then I would ask to see the service manager/ dealer principal where the subjects of trading standards and Mercedes Benz UK might usefully be introduced in the conversation.
 
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If transmission oil level is low or too old, it will generally be cured by topping up or flushing and replacing totally new transmission fluid
However, there is a better solution (short of a transmission overhaul)
I find that certech ceramic repair gel is able to solve slippage problems but it may take some time to see results (about 20~50 kms)
You may need up to 2 syringes (in Singapore, it's sgd80 each)
 
If transmission oil level is low or too old, it will generally be cured by topping up or flushing and replacing totally new transmission fluid
However, there is a better solution (short of a transmission overhaul)
I find that certech ceramic repair gel is able to solve slippage problems but it may take some time to see results (about 20~50 kms)
You may need up to 2 syringes (in Singapore, it's sgd80 each)

Wow, that sounds, with great respect to you, like wishful thinking. I have an ancient (380K Kms) MB 300CE-24 with 5 speed auto box. Last year it was, occasionally, refusing to engage reverse. New fluid and filter have corrected the problem for the last 18 months and over 12K Kms. I know it'll need a rebuild one day but I would think twice about 'miracle additives'.

Can you be more specific about your experiences with certech ceramic repair gel?

Any comments from elsewhere?

RayH
 
Can you be more specific about your experiences with certech ceramic repair gel?

Any comments from elsewhere?

RayH

It's mostly all he's mentioned since joining, and this is nearly a 2 1/2 year old thread resurrected! Sounds like a magic, cure all solution!

I had my gearbox overhauled earlier this year (96 SL500), prompted by slippage and jumping gears with a clunk under kickdown. The seals were perishing, causing loss of pressure, so were replaced, along with the pump, which couldn't cope with the newly found pressure. The clutches were fine, and this was at 146k miles.
 

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