VCCA Home Forums TECHNICAL - GENERAL Mechanical - Engine, Trans, etc 41 ton and half - 4 speed transmission issues

Frequently having trouble shifting up or down. Wondering if transmission was synchronized ?
I have an option to install a 55 Chevy truck 4 speed or a 66 Chevy truck 4 speed ? What will either one of those swaps require ?

A 1941 truck 4 speed is non synchronized. You must take your time and double clutch all shifts. it takes practice to learn how to do it.

Hi Fred

As chevy b said, 4 speeds in 1941 were not synchronized.
They also used straight cut (spur) gears.
Because of this, they had a sound all their own.
I happen to love this sound and think it's part of the charm and character of old Chevrolet trucks, and I wouldn't want to trade it away.

Different transmissions have slightly different gear ratios so each takes a little getting used to for the double clutching process.
I've be doing it all my driving life so I don't have a problem with it.
I'm sure you'll get the hang of it with time too.

Thanks. Good to know. Ill sure consider that.

Good to know. Thanks

Consider it another anti-theft device.

Good One.

Many years ago a friend had a '43 Chevy 3/4 ton pickup in rural Oregon. Yes, I confirmed that title date by the riveted on factory cowl tag. I had an idea it was a pretty rare truck but I didn't know how rare until I joined the VCCA years later. It too had the non-syncronized 4 speed. I had a later 4 speed we looked at putting in there. If I remember correctly the bolt pattern was completely different. Okay we will just switch out the bell housing. No can do because the clutch, and brake pedal pivot are riveted to the cast iron bell housing. If we had known - the alternative would have been to install a truck 3 speed from that era. Would have bolted right in and is the same length as the 4 speed. 2nd, and 3rd gears are syncronized. Makes for a much easier traffic friendly driver.

I have older cars that are non-syncronized in any gear. Along with a floor starter it is a great theft deterrent.

Art

A 3 speed would not be a good solution for Fred's 1-1/2 ton Chevy, but it is the best way to increase your driving pleasure if you have a smaller truck with the old "spur gear" 4 speed transmission.
I was not sure about the bolt pattern for the later transmissions but it occurred to me that Fred's truck might have an enclosed driveshaft. If so, this would be another hurdle to jump for a transmission update.
I drive my 1936 Chevy 1-1/2 ton truck as often as possible. Double clutching is a fun skill to learn and becomes second nature after a while. My 18 year old Grand Daughter learned to do it.
Fred, We have an Eldon in Missouri. Is that your Eldon?

Mike

Thanks Mike, I appreciate the input. I like keeping things original. I'll work on my double clutching. Only driving local, on County roads.
Yes, Eldon, Missouri, near Rocky Mount.

Ill stick with the 4 speed as I have enough other things to do on the truck. Hasn't been on the road since 1976. After years of work, Best part.....it starts and drives every time.

So I have never driven one which I should put on my list. Learning wise, is it easier shifting up than down?

It's difficult to say. Gonna work on my double clutching for now.

Hi old216

It CAN sometimes be easier shifting down.

For example, when rounding a corner, you coast or brake down until the engine is at about idle speed, clutch in and throw the transmission into neutral, clutch out, continue coasting or braking down until the truck itself is moving at the speed it would be with the engine at idle speed in the gear you are going for, clutch in, shift into gear.
Just a matter of timing, and it'll soon be second nature as Mike said.

In most all other cases you need to use the gas to adjust/synchronize the engine speed to the truck speed in the gear you are going for.

i understand and when i firtst got her running i had to turn off the motor and start out in gear i wanted like reverse or 1srt. As i said only driving local gravel roads or quiet county roads. If I ever hit 40 mph it will be a big day. Shows 26K on odometer and looks like its probably right. Field to field with occasional trip to town back in the day. Its been fun.

You should not have a problem putting it in first or reverse with it running. If you do you may have a clutch adjustment problem.

I agree with Old216. You should investigate the clutch system. It could be as simple as it needs adjustment. In any case you should be able to shift into any gear with the clutch pedal depressed and the engine running while the truck is sitting still. If the clutch is not working properly I doubt if double clutching will stop the grinding.

You can shift a manual transmission without clutching while driving That is a different skill set than double clutching.

Here is a link to a youtube vidio with a guy driving a 1941 chevy 4 speed truck.

A fun one to watch.
https://www.youtube.com/watch?v=FelG0cSgTS0&pp=ygUdMTk0MSBjaGV2eSB0cnVjayBoYXVsaW5nIHdvb2Q%3D

Adding the 2 speed rear axle really adds to the shifting excitement.

Especially on a hard pull where you need to "split shift". 🙂

Fred,
I sold a '41, former fire truck, a couple of years ago. We still have four '40-'46 COE trucks in the barn. I have a small stash of parts. If you need anything, I might be able to help. If 26K is original miles, your truck should be pretty nice. Got any pictures you can post for us truck junkies?

Mike

573 864 6539

Gonna look into that clutch adjustment. Thanks

Love those COE. Will look into my parts needs. Thanks !!

As a new sign on, all the information has been great. Thanks so much.

Just watched the YouTube video. New appreciation for straight cut gear transmission sound.