ml70 gearbox stuck in 1st/2nd

[m and a cars]

hope someone can help! on test drive car goes into reverse,neutral or drive no problems.when in drive it just doesnt seem to go through the gears and is stuck in first or possibly second.plugged it into my snap on solus and loads of codes came up,half of them i was able to erase,but 147-gears implaussible or slipping,something about N2 and N3,cant remember what exactly now stayed.
after all this we have replaced the conductor plate,removed valve plate,checked all the springs(all were fine).put new oil and filter in,and test drove it.guess what! same problem.it just wont shift out of first.plugged in again and only code that came up was 147-gears implaussible or slipping.

any idea would be great!

 

[Steve@Avantgarde]

Sounds like you have a duff battery and there isnt enough juice in it to power up the EHCU on ignition position 2 and its throwing it straight into limp mode. Check the cranking voltage of the battery, anything less than 9.6v its fair to say it needs replacing.

 

[MB TECH WARRINGTON]

Have you checked ecu for oil ingress?

 

[tony jr]

This sounds like it could be something as simple as a failing battery and the low voltage caused the gearbox to go into limp mode

 

[EuroCLK320]

Mine did this when the fluid needed topping up but battery is the usual cause.

 

[m and a cars]

ah,will try the battery,the car was stood for a while and needed to be jump started,but started ok since,even though it takes forever to start due to glow plugs not working.alternator is charging perfectly,and battery is showing 12v on the meter when car is turned off,but havent tried the battery while turning over.also will check if the oil is coming through the connector on the bottom.havent had much time on it today,but fingers crossed its something as simple as the battery!thanks for your replies guys

 

[m and a cars]

replaced the battery today,and still same problem!
I'm losing my patience with the ****** thing,
any ideas?

 

[stumo]

I think you can only clear the full limp home mode of that gearbox using star diag.

 

[m and a cars]

surely if my solus can read and delete fault codes it should be able to do it?

 

[stumo]

surely if my solus can read and delete fault codes it should be able to do it?

Depends if it can delete codes in the seperate trans controller, or just in the engine ECU. My carsoft multiplexer can delete trans codes from the EGS (gerbox) controller, but I believe even it cannot reset that 2nd level of gearbox limp home lockdown. I think it is some sort of safety lockout to prevent further damage.

 

[m and a cars]

with the solus i can access the transmission ECU and only code that was there was 147-gears implaussible or slipping,but now it comes up with another code about N2 and N3 which I'm assuming is to do with speed sensors.

 

[Steve@Avantgarde]

Possibly. But as someone said you ideally need star to ensure its all cleared properly. I have an snap on ethos tool as well as star and the ethos wont always read and clear all levels of fault memories, not just Benz but BMWs and VW's also.

 

[m and a cars]

now i just need to find someone with star diagnostics,also i have checked the electrical connection on the gearbox and the socket was indeed full of oil,so new socket ordered from MB,another thing worth trying! thanks guys

 

[m and a cars]

right,replaced the socket bush as that was covered in oil,checked ecu for oil also,the connection between the ecu and gearbox and all seems fine,but still coming up with 147-gears implaussible or slipping,and now i really dont know what to do apart from replacing the whole box!!!

 

[Steve@Avantgarde]

Was that on a star machine?

 

[Alex Crow]

what swarf was noted in the sump?

 

[m and a cars]

hi yes,same code as on my solus,so that was £70 plus tha vat wasted haha!
no swarf or metal bits in the sump,as seems fine,next step is replacing transmission ecu i guess,and then finally stripping the box down and looking for obvious mechanical faults

 

[Steve@Avantgarde]

£70 for a star test??!! Sorry chap but you got stitched, most of us do them for free or a drink!!

I think you could be looking at the electro plate now.

 

[m and a cars]

whats an electro plate? i normally charge £10 for snap on diagnostics,but most of the time do them for free,as im doing other jobs for the same person,but thats what the guy wanted,as its 10k worth of kit apparently¬!

 

[tony jr]

You could try giving these guys a ring They managed to change my valve body and electroplate (think they charged around £135 for the electroplate plus 1h labour, oil and filter):

Technical Automatic Services Ltd.

TELEPHONE: +44 (0) 1206 386303
MOBILE: +44 (0) 7715 011601
FAX: +44 (0) 386307

Automatic Transmissions Centre, Unit 22,
Waldegraves Business Park
West Mersea
Mersea Island
Colchester, Essex.
CO5 8SE
Email: info@auto-transmissions.co.uk