W210 Gearbox, changing down from 5th to 4th under load over 70mph

[stuboy]

Hi Chaps, my W210 has just developed a fault where if i put to much load on the engine the gearbox changes gear from 5th to 4th. This is new, its consistent, and it will not then change back into 5th. I have to slow down and take the load right off then eventually it will change back into 5th. It ignores me trying to change with the tiptronic too, it will change down but not back up.
I had the battery disconnected to do some welding on it the previous week, do u think i should try a gearbox reset?
Any other thoughts?
Regards
Stuart

 

[bob6600]

Firstly, you should read and then clear any codes, see which ones come back. Ideally on a decent diagnostic system, STAR if possible. If the gearbox oil hasn't been changed in the last 40k miles, get it done.

 

[stuboy]

Gearbox oil never changed its done 150,000 miles, could it be low do you think?
Can you recommend a dip stick for it or do i have to take it to Mercedes?
I can get it on my mates ramps tomorrow is there anything i can do without a dip stick?

 

[Larkone]

Gearbox oil never changed its done 150,000 miles, could it be low do you think?

Not just possibly low but the oil which provides cooling, lubrication and drive will be completely knackered. Just changing the gearbox oil will make a real difference to how it drives even if it doesn't fix your current problem.

 

[stuboy]

Also could you recommend dipstick, oil and filter, i think it will be worth changing it and see what happens. Should i do filter or could i just change the oil? My Transmission is a 722618 02 652963 so that's a 722.6?
Stuart

 

[bob6600]

Plenty dipsticks on ebay, you need one for 722.6 gearbox. Remember this is a tool and so will not go all the way in and should not be left in the gearbox dip tube. Change the oil, filter and pilot bush. Oil needs to meet 236.10 or newer, currently 236.14. List here

MB 236.14 - Automatic transmission fluids (ATF, Specification 236.14) - Mercedes-Benz Specifications for Operating Fluids

722.6 dipstick | eBay

 

[Trickythemerc]

Gearbox oil never changed its done 150,000 miles, could it be low do you think?
Can you recommend a dip stick for it or do i have to take it to Mercedes?
I can get it on my mates ramps tomorrow is there anything i can do without a dip stick?

I have a sealey dipstick for sale PM me

 

[DrNick]

When mine started doing this,it wasn't the gearbox, it was the engine. A lack of power was causing the box to go for a differnt gear to compensate.
In my case it was an inlet airleak upsetting the mixture. Fixed that and the gearbox went back to normal.
Done any work on the engine recently?

 

[stuboy]

When mine started doing this,it wasn't the gearbox, it was the engine. A lack of power was causing the box to go for a differnt gear to compensate.
In my case it was an inlet airleak upsetting the mixture. Fixed that and the gearbox went back to normal.
Done any work on the engine recently?

Nope not on the engine, i recently fixed the exhaust havn't touched the engine since last filter change

 

[stuboy]

Just to update on driving it today, had to pick some people up and as i didn't get over 60 the gearbox was smooth. The only time it seemed to rev a little high was going up a hill, but there were 3 of us in it. I am hoping its just run low?

 

[DrNick]

My W210 had two issues like this.
The first was as above, when an airleak dropped the power output, leading to the gearbox looking for more torque. This leads to higher revving for a given load, or the box changing down at lower loads than before.
The other which lead to severe flaring (engine revving like mad but not much acceleration) was due to low gearbox oil, traced to a piinhole leak in the ATF pipes. This made itself obvious with oil sitting in the plastic shield below/near the radiator in my case. This was caused by corrosion on the pipe rusting through from the outside - not an uncommon issue if I recall correctly. Obviously the hole gets bigger over time!
I suppose the point is, if the fluid is low, then there will be a reason for it, and that will be a leak. But if the fluid is ok then it might be a power problem.

 

[Petrol Pete]

Gearbox oil never changed its done 150,000 miles, could it be low do you think?
Can you recommend a dip stick for it or do i have to take it to Mercedes?
I can get it on my mates ramps tomorrow is there anything i can do without a dip stick?

Not changed for 150K miles ?? don't bother measuring the level just get the gearbox serviced tomorrow.

 

[spike60]

The symptoms you describe are very similar to my w208 CLK 320 some years ago. A gearbox oil and filter cured it.

 

[BobHUK]

Hello,

I have a question regarding the dipstick length for the W210. On Ebay there are several different lengths quoted for 722.6 dipsticks. Some are listed as 920mm long, some are 1200mm, some at 1220mm, and others at 46" or 48" long. So which is the correct one for a W210 automatic box? The reason I ask is that I've noticed some oil sitting in the under engine plastic tray recently, just as NrNick described above. So now I'm worried that my auto box may be leaking.

 

[stuboy]

From what i can gather either will do as the 1200mm doesn't go all the way in so dont push it too far!

 

[stuboy]

Is the kit for a 2001 estate the same as a saloon does anyone know? want to get the correct one ordered! Most on ebay have them for the saloon but dont mention the estate. I realise I should do a full change as per this video:-

for which i will need 11L of fluid. Will a filter and partial change keep me on the road for another 6 months (5L or 7L) or could i just do a top up if that is all i need? Apart from the changing down the rest of the shifts are still silky smooth and changing it might make things worse?
A dilemma
Would love your opinions.
Regards

 

[bob6600]

Is the kit for a 2001 estate the same as a saloon does anyone know? want to get the correct one ordered! Most on ebay have them for the saloon but dont mention the estate. I realise I should do a full change as per this video:-

for which i will need 11L of fluid. Will a filter and partial change keep me on the road for another 6 months (5L or 7L) or could i just do a top up if that is all i need? Apart from the changing down the rest of the shifts are still silky smooth and changing it might make things worse?
A dilemma
Would love your opinions.
Regards

Saloon and estate are the same. Change as much oil as you can. If you don't want to flush out the TC then at least drain what you can for now and refill, don't just top it up. Have a look here

HOW TO: change the automatic gerbox oil and flush on a 722.6 'box

Hello,

I have a question regarding the dipstick length for the W210. On Ebay there are several different lengths quoted for 722.6 dipsticks. Some are listed as 920mm long, some are 1200mm, some at 1220mm, and others at 46" or 48" long. So which is the correct one for a W210 automatic box? The reason I ask is that I've noticed some oil sitting in the under engine plastic tray recently, just as NrNick described above. So now I'm worried that my auto box may be leaking.

Yep, they will all 'work' as they will all stick out of the top.

 

[stuboy]

Hi Chaps situation update. I found my old dipstick its a 1200mm one from my old car so should be the correct one, it goes in 80cm from the top of the pipe in my w210 E320 estate, can anyone confirm that is the correct amount? it doesn't really want to go any further.
I am unable to see any leaks in the system however the dipstick doesn't show anything, comes out clean! I had a litre of fluid handy so i have put most of that in and still it shows nothing even with the engine hot and running in park. Should I put another litre in until i get a chance to do a full flush? Could it have just leaked out very slowly over the years? Apart from it changing down from 5th to 4th at about 70 the rest of the gear changes are fine.
Any sage advise gratefully received.
Regards
Stuart

 

[pillow]

When I was measuring the gearbox oil level in mine it would get jammed a bit before it was supposed to.

I eventually figured out that with a bit of wiggling it would go in even further and registered correctly.

It should be between the two marks nearest the metal bit.

 

[stuboy]

Filled up to the mark when hot, now gearbox behaving itself again perfectly. Thanks for everyone's input on this
Cheers