abrupt downshift..really abrupt

I know this problem has been discussed and it is a known problem for the 5-speed auto gearbox but it just felt down weird these days

I know that occasionally during driving the gearbox when downshift from 2->1 will give u a slight "thunk" noise however recently it occured very frequently for me and the thunk not only louder but the feel of its downshift also bigger

before it happened so infrequent that it might happen once a week or sth like that but recently it happens like so many times just in a day of driving

also the gearbox also feel strange while upshift and downshift

do u guys think it is still normal for the car or I should have it check out but then again the dealer might just BS me so hopefully the techs here can share their advice to me

thanks in advance

[royaiii]

Once I brake hard, the trans shifts so hard that I think that I got into an accident. It happens mostly on my 97 E320.

[suginami]

I have the four speed transmission, and mine thunks the same way, real hard, from 2 to 1, when I'm decelerating to go around a corner, than hit the accelerator real hard. The car goes "bam" into first gear.

If I accelerate gradually after slowing down, the tranny shifts properly.

[400E]

Mine does exactly the same as Paul S's. If I am coasting to come to a red light, then the light changes and I give it too much gas when the speed is about 20 mph, it'll give a pretty abrupt downshift.

[blackmercedes]

My understanding is that the sprag (MB calls it a freewheel-unit) is bad. Joe P did an excellent post about this problem.

Dealers insist "they all do that" and ignore you, like they do with every problem that doesn't bring the car in on a hook.

My 1998 C230 has a mild case of it, and the dealer replaced the shifter bushings. Huh? Of course, it remains unsolved. Otherwise, my tranny is great, but that "clunk" is annoying. BTW, I know it's not normal, as my Dad's 1998 C230 doesn't do it at all...

[stevebfl]

Although not a fix, all the above cars except the 97 E320 would benefit from a lengthening of the control pressure cable.

There are valve body corrections that can be made but they require alterations of spring rates and/or openning feeder passages.

stevebfl, can the lengthening of the control pressure cable be done without charge??? or is there a cost???

if i want to have it done
what's the best way to tell the dealer to do it since most of the time they would just try to avoid the service like this and saying how it is normal and stuff to avoid it

[stevebfl]

Cost? I presumed you wouldn't charge yourself.

Interesting question, I suppose because a few give so easily, answers so valuable, such a question could arise. Do you work for the government?

Only someone who works for the government could ask such a question.

I don't exactly know where to find someone who will diagnose by directive, or try to put off the inevitable, but I would suggest an independent.

[suginami]

Steve, I was waiting for your answer.

It's kind of awkward to ask the question to a shop owner to get a job done for free.

It's hard to find fault with a guy who is looking out for his money, but how do you expect a shop owner to answer?

"yes, the dealer should perform it for free because if they happen to notice the problem, they should fix it for free because you're such a nice guy."

[stevebfl]

Sorry, I forgot about the "nice guy" aspect.