Not so good results from 4spd swap - Page 2 - PeachParts Mercedes-Benz Forum

lowriderdog37 · #16 03-19-2008, 11:16 AM

did I read that part number right?

123 411 01 47 072

How did you guys acquire these?

MTUpower · #17 03-19-2008, 11:19 AM

Quote:

Originally Posted by ForcedInduction;

It has a part number, I wonder how much it would cost and how easy it would be to get one?

It's got 123 411 06 47 152 stamped on it. It attaches just behind the tranny and onto the flex disc.

MTUpower · #18 03-19-2008, 11:22 AM

Quote:

Originally Posted by MTUpower;

It's got stamped on it. It attaches just behind the tranny and onto the flex disc.

My number does not work in world pac sites. I got it at the junk yard with my w123 300D N/A four speed.

peterhardie · #19 03-19-2008, 02:12 PM

...for the record, I don't have any vibration, at least none really noticeable. Lots of gear noise, some throwout bearing noise, but no vibration. Did not index my flywheel, don't have the balancer pictured earlier in this thread. Maybe I just got lucky.

I don't think you can state a fixed length for the driveshafts on conversions. If you are putting a 240 tranny into a 300, measure, measure and measure again. There are at least two different lengths of 4-speed trannys. My measurement was close but not identical to what others got for both the shafts and the shift rods.

If your driveshaft is too long, I would re-cut it. I know, $$$$, but I think you are in for problems down the road. There is a splined section that is supposed to give in two directions. That can't be good at full compression for any length of time.

Bajaman · #20 03-19-2008, 02:47 PM

Maybe I wasn't clear, the length is only a problem for getting it in. Once installed there is at least 1/2" clearance before full compression, which should be more than enough.
And as far as length goes I don't suppose that the factory is going to measure each one...

Bajaman · #21 03-25-2008, 10:17 AM

I took the tranny back out last week and took the original auto flywheel and the manual flywheel to the machine shop. The machinist said that they were both neutral??? So, I bolted just the auto flywheel on- no detectable vibration. Bolted the manual flywheel on- no vibration. Bolted the clutch and pressure-plate on- no vibration. Bolted the transmission on- Now I feel the vibration. Two possibilities present themselves. One the absence of the third mount transmitted less vibration to the body. The other possibility is that there is something in the tranny causing an imbalance. The second point does not seem very likely, as I feel the vibration with the tranny in gear, and the clutch disengaged in the driveway...
I replaced all the mounts (two engine and one transmission). I guess it's possible that the mounts are all a little stiff at this point.
Other thoughts?
bb

Bajaman · #22 03-25-2008, 10:21 AM

I forgot to add that the transmission is the newer aluminum housing, and that it seems to function normally. It shifts fine, and no strange noises.
bb

t walgamuth · #23 03-25-2008, 10:41 AM

Quote:

Originally Posted by Bajaman

I forgot to add that the transmission is the newer aluminum housing, and that it seems to function normally. It shifts fine, and no strange noises.
bb

When I get back I will be happy to ride in it and see if its the same as my 300cd.

Tom W

junqueyardjim · #24 03-25-2008, 11:07 AM

I was very happy to hear that you had it in. Sorry about the vibration. Now, going back to your first post, you say that the vibe is bad at 1600 in 4th. Not a really good rpm for 4th, but I suppose that one might use it more then I think. but then you said you can get it on the driveway also, (under no load because you are having difficulty in holding it at 1600)(also I know how long your driveway is). So, if you get the vibes at 1600 while standing still, that eliminates the driveshaft as far as I can see. No reason to spend time on that, because in your driveway you are standing still. So the problem has to be in the engine rotation and I would think that flywheel and clutch balance would be the problem. Did you move the flywheel to a different position when you had the tranny out, and did it change anything?

#25 03-25-2008, 11:10 AM

Are you sure the clutch's input shaft size is the right one?

Alastair · #26 03-25-2008, 11:31 AM

So, with no trans, but the clutch and everything there = no vibration...

With gearbox fitted as well, = Vibration...

Cause, could be bent input shaft on the transmission...

winmutt · #27 03-25-2008, 11:55 AM

I have no vibrations any more. Did you replace flex disks and center carrier bearing? How much of a bend is there in the DS at the u joint? I believe these vibrations come from improperly placed rear tran mounts increasing the angle and thereby increasing the amount the flexdiscs have to move. As the car comes of the line the rear transmount compresses considerably. The 300's came with the thicker mount as well. After I replaced flex/center bearing and adjusted to remove as much of the bend as possible I have zero vibrations. I also have the dampener but it did not affect my low rpm vibrations.

Bajaman · #28 03-25-2008, 12:59 PM

The clutch fits snuggly on the input shaft of the tranny, so I can rule that out. I would like to amend my statement a little. There seems to be two different vibrations here. One at about 1900 in 4th is the most annoying. This seems to be the one that many people have experienced. I can also detect a slighter vibration in 3rd at 1900. There is another vibration detectable at a standstill and every speed at 1600 rpm. The reason I noticed is that I will often leave it in gear while slowing to a stop. As the car slows the vibration really increases as it reaches this 1500-1600 region.

As far as transmission mount goes, I decided to go with the method gavin used in his CD conversion. I left the drivers side alone and drilled a hole in the appropriate spot on the passenger side and used a spacer behind it.

Overall, it seems like there is some inherent vibration that just gets amplified under certain conditions (like the 4th 1600 rpm thing).

winmutt · #29 03-25-2008, 05:16 PM

*cough* Doesn't that mean the transmission is not centered? Make sure it is centered and try putting some washers inbetween the frame in the mount to let the transmission hang down a bit more.

t walgamuth · #30 03-25-2008, 05:22 PM

My indie had my trans mount mounted off center slightly and I had him drill new holes so it could be centered.

What would be fine with a long driveshaft (like he is more familiar with) will probably not work with the short, tightly confined mercedes ds. It is not designed to deal with angles and a long american driveshaft actually works better with a little angle (don't ask why, I don't know).

Tom W