Trying to mod my 4 speed linkages - PeachParts Mercedes-Benz Forum

aaa · #1 10-16-2010, 07:40 PM

Trying to complete my four speed swap (617). So I started with 240d linkages, cut them up and welded them back together. 1-2 and 3-4 seem to fit fine, but the reverse rubs too close to the middle linkage and won't engage.

Anyone got a pic of what they're supposed to look like? The epc seems to have the same thing for 240 and 300.

spamman450 · #2 10-16-2010, 08:51 PM

When i did my swap, this is what took the most time. Even though the linkages where already cut, i spent a lot of time figuring out which piece went where. Can you bend it to clear the other linkage? If it wont engage try adjusting it to make it longer. I also remember installing the linkage incorrectly a few times. everything would work except for one gear. It took a few try's to finally get it right.

t walgamuth · #3 10-17-2010, 09:16 PM

YOu might be able to slip some rigid plastic tube over the bars and clamp them so you could try different configurations, or copper with a slit to allow clamping it down.

lutzTD · #4 10-18-2010, 09:13 AM

Quote:

Originally Posted by aaa

Trying to complete my four speed swap (617). So I started with 240d linkages, cut them up and welded them back together. 1-2 and 3-4 seem to fit fine, but the reverse rubs too close to the middle linkage and won't engage.

Anyone got a pic of what they're supposed to look like? The epc seems to have the same thing for 240 and 300.

not sure what your circumstances are. in my swap I ran a threading die down an additional 4 inches on each link from a 240 then just cut approximately 4 inches off the end, there was plenty of diameter to hold a good thread. no reason to weld anything. I had the original links from the same trans, did you get yours from a different style trans? maybe they are bent for the other style. I think the reverse is opposite on the two styles

JEBalles · #5 10-18-2010, 11:01 AM

Well, up here in the north, those aluminum boogers had no chance of coming off without breaking, so I was forced to cut and weld.

I just clamped the rod in the vice along one of the straightaways and used a ruler and sharpie and drew a straight line and marked a four inch length. Cut and welded so the nub was in the same orientation as before.

My reverse, when I installed it, looked like it rubbed a bit with one of the other rods, but it shifts fine with the stick, so I decided not to worry about it. I also made sure I welded it back perfectly straight.

charmalu · #6 10-18-2010, 12:01 PM

When I did my 4-spd swap, I used the all one piece transmission from a 83 240. also used the rods and shifter from same car.

When I installed the shift rods, I cut 4 in off 2 rods and think 3 1/2 on the other one. I did no welding.
I ordered 3 new aluminum ends. (was easier than R&Ring the bushings)
I mounted the ends to the transmission. attached the aluminum ends to the shifter. held them both horizonally, over lapped on on top of the other. then marked with a felt tip pen where to cut and how far back to rethread the rods.

I made note as to how much thread was on each end of the aluminum piece, and made them the same.

I did have to tweek the rods to keep them from rubbing. thought I was never going to get just right. the reverse was the most problem as I remember. and it still just slides by the other rod next to it w/o rubbing.

Iam not positive, but think it is a 10mm die that I used to rethread the rods. don`t remember the exact pitch. have the thing out in the shop.
as I remember the rods are a little thinner, but cut the threads and things screwed together ok. been grinding gears past 1 1/2 yrs ok with it so far, and it hasn`t fallen off.

AS lutzTD said, the rods from a earlier box will have different bends and maybe length, so if different rods are used will complicate things some.

JEBALLES, you probably could have cut the rods off at the screw on piece, and still have enough rod to thread and cut to your new length. also be sure to add anti-sieze compound to the threads.

Charlie

JB3 · #7 10-18-2010, 01:38 PM

I cut and welded mine too when I did my 4-speed swap a couple years ago, not for the same corrosion reasons, but because I had no die with me at the time.
The big question is when you did this, did you first mark the orientation of the bends in the rod itself? With the slight bends in it it, what I did was mark a straight line down the longest sections of each rod, than cut, remove the 4.5 inches, then welded the back together so that the rod itself was just shorter in that section, but the bends were still as they were and the ends were still in the same orientation.

I took the 4.5 inches out of different parts of each rod, where I though it would be easiest to lose. then after that, I tweaked them a little, and it it was fine for shifting.

I bet one of your bends is reversed or something causing the bind.
Heres a pic of mine after I welded them and ground them flush-

JEBalles · #8 10-18-2010, 03:35 PM

I didn't think about ordering new ends, but I still would've had to get the die, too, like dropnosky.

And what's this about 4.5 and 3.5 inches? I was told 4 inches exactly was what you were supposed to shorten, that's what I got my driveshaft shortened.

charmalu · #9 10-18-2010, 10:19 PM

Well that is the way they lined up when I overlaped the rods on the aluminum ends. I didn`t measure first, just marked them where the lined up. I think it was the reverse that was the 3 1/2 inches.

Charlie

lutzTD · #10 10-18-2010, 10:25 PM

I got the die at Sears. bought 2 because of the threat of getting cheap chinese crap. surprisingly the Sears die did very well and one die cut sharp for all three rods.

JB3 · #11 10-19-2010, 08:11 PM

Quote:

Originally Posted by JEBalles

I didn't think about ordering new ends, but I still would've had to get the die, too, like dropnosky.

And what's this about 4.5 and 3.5 inches? I was told 4 inches exactly was what you were supposed to shorten, that's what I got my driveshaft shortened.

Now I can't remember what exactly I cut out of mine back when I did my 4-speed swap, but I figure a spread between 3.5 and 4.5 removed would all work. It would just end up changing the neutral position on the stick. As long as the shifter could still move into gear without interference in the cabin and the amount removed was the same length on all the arms, or especially 1-2 and 3-4.

The shifter linkage arm length change is way more forgiving than modifying the drive shaft.

charmalu · #12 10-20-2010, 01:16 AM

The nutural position of the stick won`t change, if the rod is placed through the holes in the shift fingers of the shift gate to keep them lined up while adjusting the shift rods.

Charlie

apsaulters · #13 10-20-2010, 03:21 AM

As a sanity check, make sure the shift levers on the transmission are properly adjusted. Distances for various chassis attached; image from the transmission manual FSM,

aaa · #14 10-20-2010, 05:34 AM

The version for the newer transmission would be nice.

JB3 · #15 10-20-2010, 09:32 AM

Quote:

Originally Posted by aaa

The version for the newer transmission would be nice.

You are talking about the cast aluminum housing getrag?

go on the EPC and punch in a 240 manual VIN number and look at the tranny diagrams. Heres a VIN from an E-bay 1983 240 4-speed which probably has that tranny-

WDBAB23A0DB384028