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Can't engage auto-manual

1K views 4 replies 2 participants last post by  hangup 
#1 ·
I have a '98 C43 with 112K. I rarely use the manual shift side of the automatic but the other day, I went to downshift manual for a pass and couldn't move the selector to the left. Any thoughts? I can't imagine anything getting down through the console. Anyone ever experienced this?
 
#2 ·
mine got stuck a while ago and I eventually got around to fixing it. has been working for over a year now w/o any issues.
search for a DIY.
you can take the selector module out, disassemble it, clean it, oil it, etc.
you might need a new selector switch too, i needed it. contacts wear out on it.
 
#4 ·
it's a top side job.
i can't find a good DIY with pictures, so here is the textual description.
it's easy, but don't rush.

it's a top side job.

the handle has a little ring at the bottom.
turn that. (i don't think direction matters, but don't overdo it, should be able to turn it without any tools). pull the handle straight up.

note the area where the stick is coming from.
there is a plastic piece around it.
pull that up.

now open the cup holder slightly, reach under the outer wood trim and pull that up.
disconnect cables, put aside. don't drop any of that wood trim, it's expensive.

now pull up the plastic piece directly in front of the wood trim you just pulled out.
it's kind of like an ash tray. this is not the piece that opens and closes. this is just a little rectangular plastic tray.

under it you'll find two screws, one on each side. take those out.

open the under arm rest (the bottom drawer).
there are two black screws in the bottom, take those out.

now the tough part. phone and antenna cables have to be wiggled around a little and you'll be able to pull up the entire arm rest piece. sometimes the shifter handle gets in the way, it might be easier to leave it in gear rather than in P, but i usually manage to get it out in P as well.

now you have 4 hex screws to undo, a few cables and the clip on the connector that connects the selector module to the tranny.
here i found a rope ring useful. hang it on the mirror and hook the tranny lever to it so it's doesn't drop down and you don't need to get under the car and get it.
try not pulling and pushing on that lever or you might be in the wrong gear when you put everything back together.

once you have the shifter module in hand examine the bushing at the bottom.
what bushing? if you don't have it right on the lever (also called "intermediate lever", that's the thing that pulls on the tranny connector that you've just unhooked) get one and install it. you might want to plan ahead and get it anyway, it's cheap.
you can get under the car and try to find it, if you find it you'll be able to see if you have the bushing or not, but you might not see if it's in poor condition or not.
usually high mileage cars just don't have it.
it's not critical to have the bushing but it improves the feel and reduces noise.
might as well do it while you are there.
i didn't know it was supposed to be there so i had to do the whole thing twice.
anyway, enough about the bushing.

this post here has nice pictures of the module,etc:
http://www.benzworld.org/forums/w21...ctor-position-recognition-switch-removal.html

keep in mind that some people (myself included) who attempted to fix the selector switch (the little electronics module inside the shifter module) had to order a new one at the end of the day. it really doesn't look like it's fixable. I'm not sure why that is, i'm familiar with electronics, i've cleaned it, even attempted to rebuild the partially worn out copper pads on the board, still no good.
before I took my shifter module apart to regain the "manual" speeds (not really manual, but you know what i mean) i never noticed any problems with the shifter module, but once i took the thing apart i started getting a lot of issues, it wouldn't be in the right gear, LEDs won't come up, etc, etc. sometimes i had to wiggle the shifter handle a few times to get it to recognize the input properly.
once i replaced the selector switch module (it wasn't outrageous, i think i spent $60 or so, but don't quote me on that, it's been a while) everything worked fine.
so be on a lookout for this.

when you bolt the shifter module back in and reconnect all the cables, carefully test the car on your driveway, go through the gears, etc.
it's much quicker to go back and forth at this point, w/o having to undo the armrest every time :)
also, when bolting the shifter module back in try to center it correctly and use the star pattern on those bolts.

overall having done this two times i think it's a nice DIY especially if you have a backup car in case you need to get a replacement selector switch :)

sorry for the long post and no pictures.
 
#5 ·
forgot to mention that the bushing is really easy to put on when you have the shifter module in hand, just take it to the bench with a vise and you'll be done in 10 seconds.
trying to put that bushing from under the car is a PITA! just not enough room down there.
it usually requires special tools that ain't cheap, and/or is a huge waste of time and a major cause of suicide among C43 owners :)
this is much easier when going from the top.
 
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