Swapping a non syncro 3 speed - The 1947 - Present Chevrolet & GMC Truck Message Board Network

66gmckid123 · 10-24-2010, 07:59 PM

I have a question here, I've got a 66gmc fleet-side. It has the original 3 on the tree,( non-syncro) first gear. I have a 80 Chevy truck 3 speed. I was wondering if it would be possible to swap this transmission in, while still being able to keep it three on the tree. A tired 283 is my motor, hopefully soon I will be putting a .30 over 327. I really want to keep the 3 on the tree, so I was wondering if the shift linkage would work with this tranny. I know it won't fit the bell housing I have, but I plan on putting in a different one. Hopefully someone has tried to do this, and can help me out.
Thanks.

raycow · 10-25-2010, 08:48 PM

There are actually three issues here.

One is the bellhousing, which you already know about, but the only difference is the center hole diameter. If you replace the front bearing retainer on the 80 transmission with one from a PASSENGER CAR Saginaw 3 speed, you can keep your stock bellhousing.

Second is the shift linkage. The problem is that the shift arms on the Sag are in a different location from the 4 bolt (non-synchro) 3 speed. There is no bolt-on fix for this. You will just jave to bend the linkage to fit.

Third is transmission length. Some 60-66 trucks used a short version of the 4 bolt transmission. If yours measures about 16" from the bellhousing face to the rear seal, you will have to replace your driveshaft or shorten it. If your transmission measures about 21", you should be good with the stock shaft as-is.

Ray

66gmckid123 · 10-26-2010, 11:10 AM

Thanks for replying. This is basically what I figured I would need to do. I was curious if you or anyone you know had bent the shift linkage to work? This is my main concern.

raycow · 10-26-2010, 05:45 PM

I have bent linkage for some car transmission swaps, but not specifically for this swap in a truck. The way I did it was to make a pattern from stiff wire that I could still bend by hand. When I got the pattern to where I liked it, I transferred the dimensions to the original linkage and heated it with a torch and bent (or straightened) it hot.

There were a couple of times where I needed longer rods than the originals, so I made those from soft steel rod stock which I think was about 3/8". I couldn't put sharp right angle bends on the ends like the factory did, so I threaded those and used clevises or heim joints or other right angle fittings that looked like they would work. It really isn't difficult once you get an idea of what you need. A good hardware store is your friend.

Ray

10-24-2010, 07:59 PM	#1
66gmckid123 Registered User Join Date: Jul 2008 Location: Shoreline, WA Posts: 26	Swapping a non syncro 3 speed I have a question here, I've got a 66gmc fleet-side. It has the original 3 on the tree,( non-syncro) first gear. I have a 80 Chevy truck 3 speed. I was wondering if it would be possible to swap this transmission in, while still being able to keep it three on the tree. A tired 283 is my motor, hopefully soon I will be putting a .30 over 327. I really want to keep the 3 on the tree, so I was wondering if the shift linkage would work with this tranny. I know it won't fit the bell housing I have, but I plan on putting in a different one. Hopefully someone has tried to do this, and can help me out. Thanks.

10-25-2010, 08:48 PM	#2
raycow Registered User Join Date: Mar 2003 Location: San Francisco, CA USA Posts: 2,454	Re: Swapping a non syncro 3 speed There are actually three issues here. One is the bellhousing, which you already know about, but the only difference is the center hole diameter. If you replace the front bearing retainer on the 80 transmission with one from a PASSENGER CAR Saginaw 3 speed, you can keep your stock bellhousing. Second is the shift linkage. The problem is that the shift arms on the Sag are in a different location from the 4 bolt (non-synchro) 3 speed. There is no bolt-on fix for this. You will just jave to bend the linkage to fit. Third is transmission length. Some 60-66 trucks used a short version of the 4 bolt transmission. If yours measures about 16" from the bellhousing face to the rear seal, you will have to replace your driveshaft or shorten it. If your transmission measures about 21", you should be good with the stock shaft as-is. Ray Last edited by raycow; 10-25-2010 at 09:26 PM.

10-26-2010, 11:10 AM	#3
66gmckid123 Registered User Join Date: Jul 2008 Location: Shoreline, WA Posts: 26	Re: Swapping a non syncro 3 speed Thanks for replying. This is basically what I figured I would need to do. I was curious if you or anyone you know had bent the shift linkage to work? This is my main concern.

10-26-2010, 05:45 PM	#4
raycow Registered User Join Date: Mar 2003 Location: San Francisco, CA USA Posts: 2,454	Re: Swapping a non syncro 3 speed I have bent linkage for some car transmission swaps, but not specifically for this swap in a truck. The way I did it was to make a pattern from stiff wire that I could still bend by hand. When I got the pattern to where I liked it, I transferred the dimensions to the original linkage and heated it with a torch and bent (or straightened) it hot. There were a couple of times where I needed longer rods than the originals, so I made those from soft steel rod stock which I think was about 3/8". I couldn't put sharp right angle bends on the ends like the factory did, so I threaded those and used clevises or heim joints or other right angle fittings that looked like they would work. It really isn't difficult once you get an idea of what you need. A good hardware store is your friend. Ray



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