VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1937-1945 Shift Linkage Adjustment

Hello all,

I haven't posted in awhile but always check in about everyday to see what's going on!!

Anyway, was wondering how difficult it is to adjust the shift linkage on a 41 Special Deluxe.

My car does not have the vacuum shift assist but shifts pretty good but it don't always get all the way into 2nd gear when I am upshifting so I thought I might try adjusting the linkage.

Thanks in advance for any replies. I bet Mike Buller has done this before!!

Kevin

I would think lengthing the rod that shifts the transmission into 2nd gear would help.

Thanks Chevgene,

Makes sense.

Kevin

One thing you might look at is the clutch rod clearance. Had the same problem with my 48 going into second gear. If you can see the shift lever move ever so slightly when depressing clutch, you may have to heat the 2/nd/3rd shift rod to clear the clutch rod. I had to bend mine about 1/4" so the clutch rod wouldn't hit the 2/3 shift rod. Just a thought here.

Jim.

Wow Jim, I never thought of that. I will check that tomorrow. We have a car show to go to so I will get plenty of chances to check that.

Thanks

Kevin

Hi Kevin,

My advice is to do an Advance Search of our past posts using the word "Linkage." Under Display Name use "Mike Buller." For the Date Range put Newer Than "5 years" and Older Than "1 month." This will give you a good selection of articles on linkage problems, and our attempts at resolving them. Try to take the time to read all the posts and come up with your own list of best advice. I have removed and played with my linkage at least 10 times in the years I have owned my car, and will do so again when I finish my latest project (switching frames and body work) and am still picking up good advice from our fellow chat members.

I am still experiencing some grinding when I shift into 2nd gear because of worn transmission parts. To eliminate my grinding I double clutch. I can do this easily because I live in a community that 90 percent of the roads are at posted speeds of 35 MPH or less. So I am not pulling out into faster traffic, and needing to shift in a hurry. If I was I would have had my transmission rebuilt. When I bought my car 11 years ago it didn't come with the vacuum assist. So I have learned to shift with out this convenience. To me it is a reminder that I am driving a very old car with a lot of older technology on it, and I enjoy that. I like sticking my arm out the window to signal turns, and to listen to my old radio on a station with music of the 40's and 50's.

Your first step in any of your repairs should be to check your manual. The least you will find out there is the correct names of some of the parts. Next check the diagrams in the Chevs of the 40's parts catalog, and then do a thorough advance search of our old Chevy chat posts. I try to do all my searches using only one word, ie. linkage, or shifting, or transmission.

Best of luck, Mike

P.S. Please keep track of the steps you take and post them with your results. Here is a link to a good starting point.

Transmiission won't shift

This is good advice. If your car has had one of the vacuum shift eliminator kits installed you will notice that the replacement shifter arm has two holes. On some cars you can use the hole closest to the end of the arm, which will give you a little more leverage, and make it easier to move the shift lever. On other cars, you must use the other hole, or the shifter rod will hit the clutch throwout lever before the gears are fully engaged. As far as lengthening the shifter rod goes, that will do nothing more than change the position of the gearshift lever inside the car. It will not push the gears farther into engagement. Lengthening or shortening the rod will not change the amount of travel in the shift lever or linkage. There is plenty of travel in the linkage to fully engage the gears unless something, such as hitting the clutch throwout lever, interferes with that travel

I struggled with this very same problem on my '48 for quite some time. It also had the vacuum shift removed. A few weeks ago, I finally got the linkage adjusted thanks to a lot of help here and particularly from instructions someone posted last fall and unfortunately, I didn't keep the person's name. However, I have the instructions which are quite lengthy and I would rather send them to you via email. One thing I discovered was that I could not use the manual for any adjustments, particularly for the spring clearance at the end of the steering column. I believe someone mentioned this above but I will mention it again and that is the second to third rod is extremely sensitive and the adjuster should only be turned one turn at a time. Beamer

Beamer,I would really appreciate a copy of those instructions if you could e-mail them to me

Thanks everyone!!!

Today when we went to the car show, I didn't notice any clutch / shifter interference as I worked the clutch.

Mike, I always appreciate your experience! Beamer, I would like a copy of those instructions if you could please. PM for email address.

Thanks again!

Kevin

Just read your post and I have also been fighting shifting to second gear. Believe vacuum shifting lever has been installed since I see two holes in the lever. Previous owner tried to lengthen the shift arm on the column by welding in a piece. This is not the shift lever in the car but the one under the hood. I would appreciate any help you can provide including the instruction to set everything up. Realize I will need to find the arm which was botched up and replace it before trying to set everything.

Hi drlenn,

If you decide to not use the vacuum assist shifting device here is the parts you need. Send me a PM if you are interested in purchasing them from me.

Thanks, Mike


http://i1321.photobucket.com/albums/u560/41chevymike/IMG_1585_zpsfc2d1414.jpg


http://i1321.photobucket.com/albums/u560/41chevymike/IMG_1582_zps0a3411d3.jpg

I emailed the adjustment instructions I used to everyone who asked for them either in this Forum or via PM. If you asked and didn't get them, let me know and I will send them again. I won't be able to do it though until next Thursday as I am going away for a few days. Beamer

Thank you Beamer!

Kevin

The old Chevy linkage was complicated looking but actually could not be much simpler. Most people overthink it when they try to adjust it. It helps to know how all the parts work. I will try to explain it. First there is the shift lever inside the car. It bolts to the steering column and goes up and down and pulls in and out. The only thing to know about it is when it is in neutral the lever should be horizontal. The next thing is under the hood. There is a clamp device that is clamped to the steering column about an inch or less from the firewall. It looks somewhat like an old fashioned U-bolt type muffler clamp. It has a sleeve pressed into it. The sleeve is about 3 inches long, an inch in diameter, and contains a bushing for the shift shaft. The shift shaft protrudes out of this sleeve a couple of inches, and has a lever bolted to it.
This lever is what shifts the gears. There is another short lever that pivots from an extension made as part of the clamp. This short lever has an adjustable rod that connects to the short lever on the side of the transmission. This lever rod combination has one purpose only. It activates, one at a time, one of the two shift forks inside the transmission. That is all it does. It has a dog on it that falls into a slot in one of the forks. It does not move any gears or push anything around. It just goes up and down about 1/2 inch and nothing more. The large lever on the shift shaft connects to the large lever on the side of the transmission by a large adjustable rod. This large rod lever combination is what shifts the gears (all 4 of them). The book gives several dimensions to be measured when adjusting the linkage. First dimension is the distance the pressed in sleeve should protrude out of the end of the steering column clamp. That distance is 19/64". The second dimension is how far the large lever shoud be from the steering column clamp. That distance is 3/4", and there is a spring between the clamp and the lever. These two dimensions combine to do one thing, limit the travel of the small lever that activates the shift forks.
When the inside gear shift lever is in neutral, the spring mentioned above holds the lever forward, away from the steering wheel. In this position the 2nd and 3rd gear fork inside the transmission is engaged. In order to engage the first and reverse gear fork, the lever is pulled back toward the steering wheel which disengages the 2nd, 3rd gear fork and activates the first and reverse one. This travel is limited by the large lever under the hood being pulled up against the end of the shift shaft bushing sleeve that is pressed into the clamp. That is why GM gives the two exact measurements stated above. As a side note, although those measurements are shown in the Chevy shop manual, I have seen a bunch of cars that varied from those dimensions but still worked fine. So here are the adjustments. First, the inside shift lever should be horizontal when in neutral. Put the transmission in neutral and adjust the large shifter rod under the hood until the inside lever is horizontal and tighten the lock not. It is done. As long as the shift lever inside the car is horizontal, it will move plenty far enough in both directions to completely engage all four gears inside the transmission.
The next adjustment is to the small shifter rod under the hood. It should be adjusted so that it moves the small lever on the side of the transmission all the way (or almost all the way)in both directions when the shift lever inside the car is moved back and forth, toward, and away from, the steering wheel. As long as the transmission will shift into all four gears it is close enough and needs no more attention. There are two things that can interfere with the shift linkage when the vacuum unit is discarded and one of the non-vacuum shift kits is installed. First is the clutch throwout lever contacting the large shifter rod. This is usually pretty easy to diagnose because if you hold onto the lever and depress the clutch pedal you will feel it. I don't remember for sure, but I think it is low and high gears where this will take place. The other problem is that sometimes the head of the bolt that pinches the large lever onto the shift shaft can contact the steering column when the lever rotates up, into the reverse - second gear position. A thinner bolt head usually corrects this problem. Jumping out of gear can be caused by either of these problems, or can result from worn internals in the transmission. If the linkage is adjusted as above, a good transmission should not jump out of gear. Grinding is caused by transmission internals or a dragging clutch, but not by linkage adjustment.

Mike, your second pic shows the two holes in the lever quite well. If there is interference between the clutch throwout lever and the shift lever, moving the rod from the end hole into the second hole will usually cure it.

Nice explanation by Latigo, but I have two comments. The first is on the 3/4" gap dimension for the spring at the bottom of the steering column. My car was set at approximately 1 1/2" for that dimension (no vacuum shift). The first thing I did was to change that to the 3/4" as shown in the manual. I could not even move the shifting lever in the car one tiny bit so I set it back at the original 1 1/2" I then made the adjustments as in the instructions I have and after a fashion, was able to shift with only a hint of grinding, and only sometimes, going into third. Before I started, I could not shift into second or third because of the grinding. I think if I turned the adjustment one more turn, the hint of grinding I now have would go away. However, it is barely noticible so I will wait for a rainy day when I don't have anything to do to make that adjustment. Beamer

Hi Beamer -

If you could not move the shift lever inside the car forward or backward (neutral position) I would suspect the following problem.
The bottom shift lever where it attaches to the shifting shaft looks like a round muffler clamp with the shift lever attached to it. With that in place and bolt snugged up, there will be about 1/16 to 1/8" protruding shift shaft showing below the shift lever. In between the sides of that muffler clamp looking thingy, you should have a "tang" that is attached to the selector lever there. If it is above the bottom shift lever or in other words, between the shift lever and the lower part of the shift shaft housing, that will be your problem. I had the same issue with my 48, the tang not in correct place. A real bugger to try to shift. Also my spring was missing along with a myriad of other problems. You really need about 3/4" more or less to get things right.

Jim

The other thing that could prevent beamer's lever from moving is if someone replaced the lower shift shaft bushing and pressed it too far into the clamp. If it protrudes more than 19/64" from the clamp it will prevent the shift lever inside the car from being pulled all the way back. That sleeve is not only a holder for the bushing, but acts as the lever stop as well. If that is the case, then increasing the 3/4" gap to a wider gap would allow the lever to have full movement. The 19/64" measurement of the sleeve and the 3/4" measurement of the gap work together to allow proper movement.

Agree. He has it shifting now but using 1 1/2" to get it to work makes me suspicious that something is between the 2/3 lever and the bushing housing. The tang is about 3/4" wide and if that is miss-located, the shifting still wouldn't be up to snuff in my opinion. Just thinking aloud here.

Jim.

I will look at the things you and Latigo have mentioned and print out your posts but for the time being, I don't think I will disturb anything since I can shift O.K. Sorry for the delay in commenting on your posts but wife wound up back in the hospital on Monday and is still there. Hope to bring her home tomorrow. Beamer