The Stovebolt Site Forums The Shop Area Engine Shop 3 speed syncro on first gear

I currently have the engine and transmission out of my truck to re-seal everything. Can anyone tell me the details on the first gear. Did this gear have syncro to keep it from grinding. I thought while I had it out I could get that looked at.

shor
Cooking Turtle Soup today!

What year transmission?

Im sorry its the original 65

Thought that there should be a synchro first that year. Didn't they start about 1962?

Well not sure about that. That is why I was asking. The syncro usually means all 3 gears.

shor
Steve

If your 65 has the original Muncie transmission (4 bolt side cover) it is not syncro in first gear. Chevy offered a full syncro overdrive trans in 66, but the regular one was non syncro. To the best of my knowledge the full syncro 3 speed (Saginaw) was not introduced until late 67. It is common to install one of the later transmissions in these trucks and you may have one. They are much larger and have 7 bolts on the side cover.
Fred

I stand corrected!

It's most likely an SM318, non-syncro 1rst gear. These aren't too bad to overhaul. The gaskets can be had fron Napa and there are several on-line sources for hard parts. The full syncro was either '66 or '67. Technically, they are both considered Saginaw transmissions, the high performance 4 speeds are the only ones officially called Muncies by GM.

Well then I am going to leave well enough be. I will change the O-ring seals, paint it and stick it back in.

Thanks guys
Shor
Steve
The turtle soup is awesome.

I have a '62 3sp+ od B-W transmission which essentially is what you have (-the od). Use the 2nd or 3rd gear synchros to stop the transmission and smoothly shift into 1st every time. You'll never 'grind gears' again.

COSMO-I HAVE THE SAME TRANSMISSION AS YOU IN MY 62 CHEVY 1/2 TON FLEETSIDE. I AM HAVING TROUBLE IN THAT THE TRANS SLIPS OUT OF HIGH ON A SLIGHT HILL SOMEWHERE AROUND 60 TO 65 MPH. ANY IDEA AS TO WHAT CAUSES THIS?I TOO DO NOT HAVE A SYNCHO FIRST GEAR. I TRY TO DOWN SHIFT TO LOW BEFORE I COME TO A COMPLETE STOP-PREVENTS GRINDING EVERY TIME!

Generally when these transmissions pop out of 3rd it is because of wear in the syncro. Also, the small spring ring on the clutch gear could have some wear. Check for bad u-joints and/or driveshaft carrier bearing that can cause a vibration that will also cause it to fall out of gear.

I find that if I shift into first right after I have come to a complete stop no problem. However, If I am going to be at the stop for a while, I will take it out of gear and sit in neutral. When I am ready to go, I need to shift into second then first to avoid grinding first gear. I don't go at all while in second, and the clutch pedal is down all the way the entire time. Years ago, I don't remember having this problem of shifting into first at a complete stop, but others described this problem with shifting into first gear. I had no idea what they were talking about until a couple of years ago when I started driving the truck again, and I had the same problem.

MR. shor, apologies if we are hijacking the thread but this is all good info. What rfs56trk said, and under the 4 bolt shift cover plate you'll see that which keeps the gear is a small machined depression and a spring-loaded ball affair... one for 1st-rev, the other for 2nd-3rd. These springs are now 50+ years old and in all probability have lost considerable 'memory' (the ability to return to original shape). I submit that this also leads to popping out of third at highway speeds.