1968 GMC 3 speed trans

[Jurassic-1]

I purchased a 1966 C-10 truck. I was wondering if a 1968 3 speed trans has a syncro 1st gear. The 1966 trans does not but I do have a 1968 trans that looks like the same trans. I am not too familiar with these 3 speeds.

[too much stuff]

If it looks like the same size case, it probably is the same as what you already have. I think 69 is when the synchro first gear was more common. The main case is bigger.

[1971 cheburban]

If your lucky you could find what they call the H.D 3 speed, I think they were behind big blocks an heavy duty apps. But they were synchro'd in all forward gears and they may have a little lower first or maybe not, but just get a good shifter for it.

[Wrenchbender Ret]

The full syncro came out in 68. Like Stuff says if it looks like the other one it is. The early one had 4 bolts in the side cover. The latter one had 6 or7 & is longer.

[19673ontree]

The syncro 3 speeds are long and look like a 4 speed missing the reverse the non sincro 3 speedes are small kinda round looking I don't have a pic handy ,,,

[Jurassic-1]

Thanks for the info. I will take a closer look at it. I am not sure it will be worth changing if I would need to change a lot.

[factorystock]

The manual transmission dept for GM in 60's was not one of the brighter spots. Running the standard 3 speed crash boxes thru 1968 was an imbaressment (Ford had a full synchro in '63). Finding a special option '66 -'68 full synchro is a rareity. All 1969 and newer standard 3 speeds were full synchro. THey will bolt in to your '68 bellhousing, but linkage rods and drive shaft may need to be lengthened or shortened.