The Stovebolt Site Forums The Shop Area Engine Shop having issues with 3 speed tranny on 54 pickup

i'm having a lot of problems with the 3 on the tree tranny jumping out of 2nd gear. it will not stay in gear with out holding it and then it still wants to jump out. acts like something hits it and it jumps out. i'm driving it everyday know and need to do so as my other truck is being worked on.
i want to install a 4 speed tranny in it. will a 1950 4 speed fit it. it is still has the closed driveshaft.

i've tried adjust the linkage but not helping. i can't put install an open drivshaft rear end in it till this summer so have to deal with this right know. ive located a 4 speed from a 1950 1/2 for a cheap price. what do i need to do. thanks

1948-54 truck 3 speed transmissions will fit.

You might try swapping shift covers first as the shift fork inside could be worn.

How about the 4 speed. The reason I want a 4 speed is there has been a few times here lately that I needed granny low to get out of where I was due to the load I had on.

four speed should be a bolt in. If my memory is correct they have the same spline on the main drive gear (input), same length, etc. Your jumping out of gear problem is common and likely will require major parts to fix. Main drive gear and/or main shaft, needle bearings, syncho drum, are suspect when these start doing that.

A 1948-54 4 speed will also bolt right in. The transmission floor cover is stepped higher to clear the taller trans and has a hole for the shifter, but those are available in aftermarket.

BTW, 1955-69 also used this same transmission but used a different tail housing and yoke for open drive line.

Having the same issue with my 61 let me know if you get some good results?

Most of the jumping out of gear problems were caused by worn out shift forks and worn out synchros. 48 to 53 used a 2 lug synchro. 54 up used a 4 lug synchro. A 4 speed will bolt right in and will probably be the cheapest solution to your problem. Depending on how much you care about looks, it used to be common to just cut a hole in the 3 speed floor panel.

nothing a piece of carpet wont cover
but i've heard that the 4 speed is a bit taller so the floor pan would have to be replace with a different one.

when i bought the truck i was told that the tranny had been rebuilt and had less than 500 miles on it. i'm beginning to wonder about that.

The 3-speed floor cover is flat.

The 4-speed floor cover has a raised "hump". All reproduction covers seem to be fiberglass.

A floor shift seal is used with the 4-speed transmission/cover.

And, a different steering-column floor-seal would be used.

here is my 4 speed i just picked up. going to order a gasket kit for it and then when she warms up it that ever happens i plan on getting it put in.
http://i942.photobucket.com/albums/ad263/bluecarpenter/2010-02-23134105.jpg
http://i942.photobucket.com/albums/ad263/bluecarpenter/2010-02-23145046.jpg
http://i942.photobucket.com/albums/ad263/bluecarpenter/2010-02-23145111.jpg
http://i942.photobucket.com/albums/ad263/bluecarpenter/2010-02-23145130.jpg

when i look in the end of the tail piece i can see the bearings in there. how does the oil stay in it?
it is definatly bigger than the 3 speed. looks like a beast.

Tim,those floor covers look exactly the same.
This is the four speed floor cover. 4 speed floor cover

While the way Tim illustrates is the correct way to make the changeover, the common way to do it 50 years ago was to cut a hole big enough to accommodate the entire hump and them put a piece of foam rubber over it for an insulator. As for the shift linkage, there is a coupling on the shifter shaft. We took them apart there and removed the shift lever and left the rest of it. It all depends on what you want it to look like.

will the u-joint from the front of the torque tube be the same size to fit the 4 speed tranny?

I'll know for sure in about two months, because I'll be changing in a 4-speed for the 3-speed in my Suburban.

I also gave up on the three speed because I did not want to keep playing with the shifter box, the linkage rods, and the shifter forks and the spring and ball detents inside the transmission. Also, the first gear in the stock 3-speed seemed a little high for the 3.55 ring/pinion conversion.

The last 1/2 ton 4-speed u-joint assembly that I used was a NOS unit that came with the correct yokes. However, it is my understanding that if you use the 4-speed-side yoke from an enclosed driveshaft transmission and the 3-speed yoke from the enclosed drive-shaft end, and a 3-speed/3-speed joint/cross, you'll be OK.

Be sure to follow the Shop Manual procedure for determining the correct number of gaskets between the ball/bell collar and the transmission.

!/2 ton rear yoke is the same on 3 speed and 4 speed.