gearbox probs e320 w124 '94' m

[michaelk3289]

Hi guys, i may have posted something similar a few weeks back but thought a new thread may get answers i am looking for

my car has the auto box, with d, 2 and 3 gears, is this the 4 speed box?

the car seems to drive and chane ok when in E mode, although doesnt kick down and very little happens when in this mode (not sure if it even should kick down in E mode)

but when S mode is selected it wont change up if you boot it, it just cuts out like there is a rev limiter but wont change up, if you go easy on the gas it seems ok but still seems like the change is not right

its with Andy at Wright tech sidcup (previously merc tech)

he has serviced the gearbox so new oil and filter, checked the valves and all looks clean and well

Andy has had the car for several days so dont know exactly what has been done but a new kick down switch has been fitted.

Andy is gonna speak with a merc gearbox specialist but i thought i would put it to the forum to try and get some ideas

 

[AMG19]

What is cutting out when you boot it? I understand it wont change up a gear but does the engine cut out?

 

[michaelk3289]

What is cutting out when you boot it? I understand it wont change up a gear but does the engine cut out?

the engines cuts but only as if it has a rev limiter, i hope i can explain it properly, it doesnt cut out completly, only like a rev limiter is kicking in and stopping the engine blowing up, which is great but it doesnt change up, which means it stutters, if i can describe it lke that, you have to let off the gas and then it changes up

any ideas???????

 

[Henry D]

What engine rpm does this happen at ?

 

[AMG19]

Air mass I can almost guarantee it. Send me a cheque for my diagnosis via post

 

[michaelk3289]

Air mass I can almost guarantee it. Send me a cheque for my diagnosis via post

so i just need to mention Air mass to mechanic

 

[michaelk3289]

What engine rpm does this happen at ?

full rpm

 

[michaelk3289]

spoke with Andy at wright tech, he is going to swap the air mass over and see if it helps, he is also going to drop the sump of gearbox (well i think thats what he was talking about) and adjust a grubbing or something

so will update next week when i get it back

 

[kth286]

I'm wondering if the car is in limp mode.

The codes need to be read.

There is a gearbox overload protection switch that will give the effect you are having - the wire/s to it could be faulty or the switch itself could be faulty.

Reset all the codes and see if that helps initially.

Do not confuse the codes meaning an electronic gearbox as you do not have electronic gearbox.

Pin 8 is the one.

The codes are the normal ones from the 16 pin plug in front of brake booster.

 

[michaelk3289]

I'm wondering if the car is in limp mode.

The codes need to be read.

There is a gearbox overload protection switch that will give the effect you are having - the wire/s to it could be faulty or the switch itself could be faulty.

Reset all the codes and see if that helps initially.

Do not confuse the codes meaning an electronic gearbox as you do not have electronic gearbox.

Pin 8 is the one.

The codes are the normal ones from the 16 pin plug in front of brake booster.

spoke with andy

he tells me there is no limp mode on this box, but thanks anyway

apparently there is some sort of adjustment in the gearbox that requires the sump to be dropped, andy has explained it but i am useless with this sort of thing

thanks for all your info and suggestions

 

[kth286]

spoke with andy

he tells me there is no limp mode on this box, but thanks anyway

apparently there is some sort of adjustment in the gearbox that requires the sump to be dropped, andy has explained it but i am useless with this sort of thing

thanks for all your info and suggestions

Ther is indeed no limp mode in this box, as I said it is not electronic, but there is a limp mode with the engine.

Is Andy a Merc specialist ?

I have seen this before where the faulty signals from the gearbox overload protection switch would not let the engine perform properly, so as to protect the gearbox.

If Andy is a Merc specialit he should be able to read the fault codes from pin No. 8 and it will likely show up bad signal from the gearbox overload protection switch, and thus the wiring or the switch itself is faulty.

Just looked at your first post and it is with a merc specialist.

Show him my post and ask him to read the fault codes from pin 8.

Tell us what codes he found.

 

[AMG19]

Just spoke with Tony from TM Motors about this. He said he has come across this problem loads of times.

Andy sounds like he is now on the right path. What he needs to do first is slacken the kick down cable. If this cures it he can then adjust the working pressure on the grub screw by the bell housing inside the box. To decrease it he must screw it inwards. If this doesnt work he will need to change the govenor.

Basically your problem is the working pressure is too high.

 

[michaelk3289]

Ther is indeed no limp mode in this box, as I said it is not electronic, but there is a limp mode with the engine.

Is Andy a Merc specialist ?

I have seen this before where the faulty signals from the gearbox overload protection switch would not let the engine perform properly, so as to protect the gearbox.

If Andy is a Merc specialit he should be able to read the fault codes from pin No. 8 and it will likely show up bad signal from the gearbox overload protection switch, and thus the wiring or the switch itself is faulty.

Just looked at your first post and it is with a merc specialist.

Show him my post and ask him to read the fault codes from pin 8.

Tell us what codes he found.

will do

thanks for info

 

[michaelk3289]

Just spoke with Tony from TM Motors about this. He said he has come across this problem loads of times.

Andy sounds like he is now on the right path. What he needs to do first is slacken the kick down cable. If this cures it he can then adjust the working pressure on the grub screw by the bell housing inside the box. To decrease it he must screw it inwards. If this doesnt work he will need to change the govenor.

Basically your problem is the working pressure is too high.

thanks for help

i have spoke with him today and he basically said what you said

i will update the thread once its done, thanks again

 

[michaelk3289]

going to go and pick the car tomoz morn.

i have spoke with andy and he has adjusted the grub in the box around seven or eight times and has slackened the cable, this hasd improved the gear change, however andy thinks it might need a new govenor

any ideas cost involved with replacing the govenor?

 

[michaelk3289]

ok so just got back from picking the car up

andy has done a great job! the car drives like a dream and changes really smoothly

he has adjusted the grub in the box around 8 times and slackened the cable

other work was carried out like checking valves etc, but i know nothing about gearboxes or mechanics of a car so got lost when he started talking about pressure

end result is fantastic