I have been having problems downshifting my 4 speed transmission. This is on a '37 1/2 ton truck with the 216 ci engine. It will not engage any lower gear. To verify I am doing this correctly, the following steps list what I am trying to do: 1)depress clutch, 2)shift to neutral, 3)release clutch, 4)apply throttle (foot), 5)depress clutch, 6) down shift (or try to), 7)release clutch, 8)apply throttle (foot). Is this the correct process? If it is, does anyone have any ideas on what may be mechanically wrong. Is it a needed clutch adjustment? The clutch seems to be fine otherwise. It allows smooth shifting from lower gear to higher. This is a real pain when I'm trying to turn a corner and need to slow down without coming to a full stop. Thanks for your help.

It should not be necessary to "apply throttle" between shifts -while double clutching.....give it a try.

Gene, 37Blue

It is helpful/necessary to raise the revs in neutral when downshifting a crash box, but keep the revs up to match RPM to road speed while grabbing the lower gear. You can use this technique without using the clutch at all, but the learning curve could be a little expensive with these older transmissions.

Gene
George33eagle is right on all points, after you get used to shifting gears without the clutch can become expensive. I learnt the hard way, clutch linkage gave out travelling on the highway. It is a matter of getting engine revs and road speed right and you can shift up or down without any problems.
Some truck drivers I know only use the clutch pedal when starting off or nearly at a stop.
Tony

Thanks guys for the answers. Sounds like I need to keep trying to learn the fine points better. I am climbing a steep learning curve about the hobby in general and with "Old Blue" in particular. It's a real hoot. I read somewhere the 4 speed was a "factory" upgrade for '37. I have pondered even replacing this with a 3 speed, which I think I recall hearing has a synchromesh feature. Any thoughts?

The 4-speed has an ultra low first gear to get a heavily loaded truck in motion. If you aren't hauling loads, I think a 3-speed would be a wise decision. I think they're a direct swap, but I'm not positive. It might not be if the 4-speed is longer that the 3-speed.

Chev Nut will be along with details, I'm sure -Bob

Most guys I know with 4-spds in the older 1/2 tons rarely use First gear. They don't carry a 'load' in the p/u - basically they use their p/u just for pleasure. So they just start out in 'Second.' I don't know the ratio's for 2nd in a four speed compared to low in a three speed; but they must be fairly similar. Lou in Berkeley, among others, would likely know that. (Lou is a real truck aficionado who has several 30's - 40's trucks including a neat '37 [I think] ambulance.)

As for the 3-spd 'working' in place of the 4-spd, I have no idea. As before, there's many guys (in) here who would know about that and it's likely they'll see your question and give you some help with this matter.

Bill.

When I was taught to drive one of these 4 speed trucks, my Dad called first Low-Low and the next gear Low, which was the one to start off in under normal conditions.
The four speed is very much like a three speed except with the addition of Low-Low or Granny gear, and it is a more heavy duty job.

My two ton truck also has a four speed tranny, and the first gear is a "Granny" gear and it is never used. I always start out in second gear which is about the same as first gear in a standard three speed transmission.

Thanks again to all for the replys. I have been using the gears higher than "Granny". The few times I have though, it seems it would have had enough power to pull about any load needed. But now "Old Blue" is only going to be to haul me and my Bride, of 31 years come next week, around town joy riding on Saturday morning to the local coffee shop and maybe a car show after some more cleaning and fixing.

I needed to get diff for my 38 3 speed and the only one I could find was a 39 4 speed.
Iwas then told I would have to change gearbox as well but it was simply unbolt 1 and bolt other in its place (gearbox driveshaft and rear axle), same clutch, thrust bearing and mounts.
Tony