Jerk in transmission, -problem solved!


Big mistake...
After that, I experienced a sudden jerk (like you´re hit from behind) at low
speed when engine and transmission were cold. After warm-up it dissappeared.
Couldn´t live with that so I let a transmissionspecialist look into it.
He took the gearbox off and changed following parts:
-converter
-both "freewheels"
-1:st, 3:rd and 4:th gears (3:rd gear looked burnt, the edges on the others
wasn´t edgesharp)
-conductorplate
-oil & filter
-all gaskets
-a greasevalve.
Got it back but the jerk was still there, but less violent.
Then he suggested to change the solenoid in the gearbox as well.
After that the gearbox performs brilliant without any jerks!!!
It goes like a dream now, really.
I suspect that loose dirt hit the solenoid at the first oilchange.
Voila, problem solved!
(It didn´t come cheap though...)


He´s doing Mecedes jobs after work with no warranty.
Maybe he can change engineoil and easy jobs but he should stay away
from modern cars like ours. He hasn´t even STAR.
I suspect he used the wrong transmission oil or didn´t fill it up the first time
with damage as a result. And he only cleaned the filter instead of change it.
Maybe debree came loose and got stuck where it shouldn´t, at the solenoid?
His garage is a mess, I say never again!!
The transmissionspecialist called the solenoid for "PWN solenoid", and I got
the impression that it´s located in the valveunit in the transmission.
When I asked him what it does he answered "it controls about everything,
including the lock up of the torqueconverter".
Anyway, I´m very happy the problem now is solved!




and the wrong signals from the RPM sensor that located in the conductor plate only,,
not have to be complete rebuild....

Glad you solve it MaaaaN...
ZAYED,,
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By the way, the transmissionspecialist called it "PWM solenoid"
and nothing else!! Sorry, will help and not misslead anyone! Fat fingers..


Know many with this problem and no one had come up with a solution.
I found it but it cost me half a leg, but on the other side I have almost
a new gearbox now!

Thanks again.




Item #35 in this pic:
Attachment 279597
side note; if you want a good upgrade for shift delay or jerking, time to replace the "2" Brown top solenoids to the Blue top solenoids, then reset the TCU, you will definitely surprise.....

ZAYED,,


But on the other hand he revealed "the bad guy" when he took the car in for the second time, "we should change the solenoid too"! Free of charge after 3,8 k dollares.
He had several digital testriggs at his disposal, but when he fitted the new solenoid he said "we have different readings". Since the tests were done with
78 C degrees heated oil, the problem probably didn´t occur the first time and everything seemed fine.
I´m just happy to be able to pinpoint the real problem in this speculative issue.
If he had changed the lot the first time, I couldn´t share this with you guys.
My joy is the sharing. But of course my smooth gearbox too!
The TCU-tune makes the car sportier too, trust me!
isn´t the solenoids for gears different from the PWM solenoid AMGEN replaced?
I might have misunderstood but was it the solenoid for the Lockup you replaced?
If so, lockup solenoid differs from the others i guess?


There are several solenoids in the gearbox (8?).
The one we´re discussing here is the Pulse Wide Modulator Solenoid.
It controls the lock-up of the torqueconvertor.
It´s situated in the valvebody that has to come off in order to change it.
The lock-up slips 1-2% when locked-up, which is completely normal.
The diagnosis in many threads is problem with harsh lock-up when the oil
is cold. So it´s makes sense that it´s the solenoid that controls this process
is the problem.
It isn´t expensive but a bit hard to replace obviously.
If you don´t have any problems, I think it´s a waste of time changing it in prevention.
just when start rolling there´s a tiny 'hookup' in lets say 5mph
Like the lookup activates in this low speed.
I almost figures this should be this way due to save fuel.
Otherwise all is good.
Been reading about blue top solenoids several hours yesterday.
I´m starting to belive i got them already.
As people are describing the function: real hard gearshiftes when flooring it - got those!
hard downshifts when throttle is released and gearbox is shifting downwards - got those!
It´s like dumping the clutch on an manual car with 'too low' gear.
And mine was faster to 60mph than it should already as std.
Last, the one that i bought the car from, his dad was working as 'boss' at a mercedes center in Germany.
As the car is retrofitted with some other small things they might have done this too

Is it possible to see color if just taking down the pan to change the filter?
Rgds.
Edit, once i timed the gearshifting in my car as i thought they were quite fast actually.
About 0.7s from when flapping the button on steering wheel.
I read someone else done the same, and it took about 1.05-1.1s
Last edited by swedepat; Feb 21, 2014 at 07:51 AM.






Title should have read... Jerk changed my Trans oil.
