E320 behaving like Boy Racer

[JonathanC]

Hi All

I have a 1994 E320 with a 5sp auto. I noticed that the gear box has been a bit slow to react with part load kickdown, which made driving it frustrating as there was a delay between putting your foot down and the gear box reacting. I have resolved this by tightening the control cable by 1/2 turn which now means the box reacts as expected and still changes smoothly but if you floor it, it hits the rev limiter before changing up! Nice if I was in a chaved saxo but not really appropriate for a merc! I have had the fluid and filter changed about 3k ago and there are no other symptoms. Obvioulsy I can slacken the control cable but then I am back to the slow response issues I had at the start. Does anyone have any ideas how I can resolve this or is this some expensive gearbox internal issue?

Thanks

 

[kth286]

JonathanC

Does it do the same in both 'S' and switch position 'E'.???

I find that when I lift my foot off the accelerator after kickdown has been effected, the gearbox instantaneously changes back up to the higher gear.

So, I find I have complete control of gear changes by using my right foot. I 'play' the car like a church organist - great fun.

Mine is a 4 speed, but that shouldn't matter.

Regards

PS. We should meet up at some pub car park and compare notes - where are you in Berks ?

 

[JonathanC]

Hi David

The car hits the rev limiter in E or S if sufficient "welly" is applied. If I lift off then the car will change up. Before I adjusted the cable the gearbox was reluctant to change down to accelerate unless kickdown was used which made for less than smooth progress. It now seems more responsive and the change points generally are as I would expect.
I remember reading in another post about the governor controlling the gearbox shift points. I believe this was partly controlled by vacuum. I know there is an adjuster on the gearbox related to vacuum but I thought this only effects shift quality - does this also influence the engine revs the box shifts at and if so how to adjust it?

David - I should update my location as I now live in Wiltshire, thanks for reminding me!!

Jonathan

 

[JonathanC]

Update - I have tried adjusting the control pressure cable to alleviate the over-reving but this hasn't improved matters. It doesn't do it all the time there doesn't seem to be a pattern although I can only vouch for it behaving like this in 1st and 2nd (and 5th - I wish!)
Auto Gearbox gurus - I remember there being another adjustment on the side of the box where the vacuum pipe enters - as the governor uses vaccum to control change points would this be worth adjusting??

 

[angus falconer]

. I noticed that the gear box has been a bit slow to react with part load kickdown, which made driving it frustrating as there was a delay between putting your foot down and the gear box reacting.

Hi Jonathan,

When my mass air sensor was on the way out I had a similar problem. New MAF=clean changes again

 

[JonathanC]

Hi Jonathan,

When my mass air sensor was on the way out I had a similar problem. New MAF=clean changes again

Thanks Angus

I think your car is a bit more intelligent than mine in that the gearbox is electronic rather than the hydraulic version mine has. The over-reving problem I believe is entierly down to the gearbox as there are no other elctronics effecting shift points. Thanks for the suggestion though - I might try and clean the MAF at the weekend and see if that makes a difference.

Thanks

 

[clive williams]

Hi All

I have a 1994 E320 with a 5sp auto. ............changes smoothly but if you floor it, it hits the rev limiter before changing up!
Thanks

Jonathon,

Have you checked the auto fluid level as mine is very sensitive to reduced level and exhibits the same symtoms. I assume its lack of fluid pressure to effect a change.

I realise that you have had the fluids changed. Was the gearbox done as well and have you got any leaks? The MB boxes are known to bend the flange of the oil pan with each progressive fluid change and extra care is necessary to ensure the gasket seals. I've noticed that tightening to the specified torque is too much on an old pan. Bolts need tightening just enough to stop distortion of the seal and be coated with loctite to stop them falling out.

Clive

500E
E320CDIT210

 

[JonathanC]

Clive,

Thanks for your comments, the oil level was correct. It seemes a fine adjustment of the control cable is necessary to get a balance between shift speed and the revs at which the change occured under full throttle. It also only seems to do it in 1st and 2nd gear, after that it changes before the red line. I have managed to adjust the cable to get the best balance between revs and shift speed/quality although it still goes into the red zone it no longer hits the rev limiter.

Thanks

Jonathan