Shifting techniques of experienced Deuce Drivers

[Karl kostman]

I have always double clutched my Deuce both up and down and that eliminates in issues completely. I also always shift the truck along with any other manual transmission vehicle into Neutral when stopped like at a light or anything like that, its much easier on the throw out bearing!

 

[Redleg130]

Drove it quite alot yesterday on backroads and I think I have it figured out. Mainly just matching speed to what gear I am in. When downshifting previously it would bounce around and this apparently was simply because my speed was too fast for whatever gear I was trying to downshift to. Orchestrating brakes, coasting, clutch and shift is starting to feel better now. It definitely is different than a standard car, but manageable.

I drove the M35 a handful of times on duty, but this was in the 90s. I didn't get any formal training, just "hey you drive this thing" so my familiarity is limited. I also have an M37 (being rebuilt) that is somewhat similar, but the extra mass on the M35 made me a bit nervous about it. I don't want to ruin or be hard on this vehicle by driving it poorly.

Thank you for the good advice. Ill summarize the tips in the original post so someone asking the same question can quickly find this. Please recommend corrections/additions if you have them.


A couple follow on questions - the max RPM is labeled at around 25/7. Between 3rd and 4th there are speeds where third is too low (approaches max RPM) and 4th feels to high. What is bottom RPM that isn't bogging engine? My guess is 15, based on sound and how it behaves, but I thought I would ask since I really don't actually know what it should sound like.

Attached is my truck that I will be using as an amateur radio "Parks on the Air" mobile ham shack. I worked in one of these shop vans in the 90s, and am happy to have found a very similar one that appears to be in very good shape.

 

[HDN]

We need more pics - that van looks nice!

 

[Guyfang]

I don't want to ruin or be hard on this vehicle by driving it poorly.

You have no idea how tough this truck is. If we could not destroy it, back in the day, (on purpose sometimes) you are not going to damage it very much. We were 19-20 years old, and dumber then tree stumps. I would take an A2 over an A3, any day.

I wonder if a 2 Niner 2 antenna, (RC 292) could be converted for your use. Simple to erect and use.

 

[HDN]

You have no idea how tough this truck is. If we could not destroy it, back in the day, (on purpose sometimes) you are not going to damage it very much. We were 19-20 years old, and dumber then tree stumps. I would take an A2 over an A3, any day.

I think the automatic in the A3 is the weakest link. It's max load is around 26000 lbs, which a fully-loaded and towing M36A3 is reallllly pushing. Makes me wonder what the Spicer's max load is - has to be at least 24000 lbs.

 

[Guyfang]

When the A3 came to Patriot, lots of of the guys were old Hawkers. They hated the A3. I got my taste of it in Ft. Bliss, out in the hind end of no place. Was not impressed. Later, in Germany, I drove one around, (as much as they would let me) to lots of the Missile Sites, and the A3 just was not half the truck a A2 was, going up the steep serpentine roads. There were other reasons also.

 

[HDN]

When the A3 came to Patriot, lots of of the guys were old Hawkers. They hated the A3. I got my taste of it in Ft. Bliss, out in the hind end of no place. Was not impressed. Later, in Germany, I drove one around, (as much as they would let me) to lots of the Missile Sites, and the A3 just was not half the truck a A2 was, going up the steep serpentine roads. There were other reasons also.

I've never driven an A2 so I don't have that version to compare. However, I feel like the A3 is at least faster than my dad's stock M37, even up-hill

Gosh it makes me want to get an M35A2, but I want my next big truck to be a 5-ton of some sort. I do miss driving a manual transmission!

 

[Guyfang]

My M-813 Drop Side 5 Ton was a runner. Even better after one of my guys "adjusted" The IP. What a beast.

 

[cattlerepairman]

FWIW, my transmission is tight and I am running 40W and it is indeed easy to shift - and it absolutely hates getting gears floated. I drive 10 speed and 18 speed trucks and I know what I am doing. My Deuce wants the clutch, plain and simple. Double clutching and rev matching on the way down, simple clutch on the way up is ok.
The wear patterns on the transmission gears are different between transmissions that are always shifted with the clutch versus those that get floated. A transmission that is always clutch-shifted is not easy to float until wear happens. I do not want to do that to my transmission, so clutch/double clutch it is, in the Deuce.

 

[Crf450x]

Synchronized transmissions should be shifted with the clutch disengaged. Doesn’t matter if it’s an m35 or a Mazda Miata. You can play super trucker if you want but it does cause cumulative damage unless you are 100% perfect every time. But you won’t be and the synchros will pick up the slack so you may not even realize you weren’t perfect until those synchros are shot from not understanding how transmissions work.

 

[Redleg130]

I initially learned to drive a manual by being stuck doing it. I arrived at a new duty station, was invited to the local bars the people in my new unit, and not wanting to get liquored up in a new place, opted to pass on drinking. Everyone else did get liquored up and when it came time to go home, they gave me the keys and promptly passed out. It was a stick shift, I knew the concept but had no practice, but got a lot of practice that night, getting lost, lurching about, stopping at gas stations for directions, getting stopped by the police for driving incompetently (officer actually was quite helpful with directions after he verified I wasn't actually drinking and not familiar with stick) and finally lurching back to the barracks. After this, I ended up getting a manual Geo Metro, which was fantastic on fuel milage at a time when fuel was 80ish cents a gallon (before 91) and preferred manuals since. They (manual transmissions) aren't often available these days.

A few years later, my wife and I got stuck in a junker car about a hour from home with the clutch out. Not wanting to be stuck we decided to use the starter to get moving and the car started, then float gears all they way home. She navigated with the street atlas for optimum route (way before smart phones) minimizing stops. We got lucky on stop lights we couldn't avoid after getting off the freeway, and made it home. Got the clutch fixed and that junker car zombied on for a few more years after that despite being awfully hard on it that day.

 

[HDN]

I initially learned to drive a manual by being stuck doing it. I arrived at a new duty station, was invited to the local bars the people in my new unit, and not wanting to get liquored up in a new place, opted to pass on drinking. Everyone else did get liquored up and when it came time to go home, they gave me the keys and promptly passed out. It was a stick shift, I knew the concept but had no practice, but got a lot of practice that night, getting lost, lurching about, stopping at gas stations for directions, getting stopped by the police for driving incompetently (officer actually was quite helpful with directions after he verified I wasn't actually drinking and not familiar with stick) and finally lurching back to the barracks. After this, I ended up getting a manual Geo Metro, which was fantastic on fuel milage at a time when fuel was 80ish cents a gallon (before 91) and preferred manuals since. They (manual transmissions) aren't often available these days.

My first car was a Jeep Wrangler with the 4.0 I6 and the 5-speed manual. After it would no longer pass inspection due to frame rot, I went on to a Toyota Corolla, another 5-speed manual. I think the modern automatics are pretty nice, but everyone knows how to drive them. With Rochester's carjacking problems, I'd like to see one of those dumb thugs get stumped by a stick

That reminds me of a story I heard long ago of an old man who was carjacked by some city punk. What the punk didn't realize was that he had to learn how to drive a manual on the fly. While being lousy at learning, his elderly hostage reached into the back seat and smacked the kid in the head with an open tacklebox, putting a bunch of hooks into his face Kid ran away and got caught later.

 

[cattlerepairman]

Drove it quite alot yesterday on backroads and I think I have it figured out. Mainly just matching speed to what gear I am in. When downshifting previously it would bounce around and this apparently was simply because my speed was too fast for whatever gear I was trying to downshift to. Orchestrating brakes, coasting, clutch and shift is starting to feel better now. It definitely is different than a standard car, but manageable.

There are some good videos on YouTube about shifting standard transmissions. Technically, with the synchronized 2-5 gears in the Deuce you do not need to double-clutch, or rev-match on downshifts but it sure does help (because the parts involved are relatively massive and spinning at high rpm and the synchros are happy if you relieve them from having to do all the work).

You can add to your list starting out with the transfer case in LOW (down to the floor), getting going in 1 (or2), shifting 3-4-5, then transfer case to HIGH and shifting 4-5. In total, that gives you 7 gears when you need closer steps between the shifts in case you are very heavy and/or the road is very steep.

I do not like downshifting the same way; the transfer case seems happy in the upshift LOW to HIGH but it is not synchronized and I do not see the need to cause additional wear in downshift situations.

 

[rustystud]

FWIW, my transmission is tight and I am running 40W and it is indeed easy to shift - and it absolutely hates getting gears floated. I drive 10 speed and 18 speed trucks and I know what I am doing. My Deuce wants the clutch, plain and simple. Double clutching and rev matching on the way down, simple clutch on the way up is ok.
The wear patterns on the transmission gears are different between transmissions that are always shifted with the clutch versus those that get floated. A transmission that is always clutch-shifted is not easy to float until wear happens. I do not want to do that to my transmission, so clutch/double clutch it is, in the Deuce.

I've stayed out of this fray until now. "Cattlerepairman" and "Crf450x" are correct. A good tight transmission should "never" be driven by "floating the gears" . That is of course if you want to keep a tight transmission. If your goal is to get a good and "sloopy" transmission than go ahead and "float"away !
Being a rebuilder of heavy truck transmissions, I can honestly say "floating the gears" is the worst thing you can do for the longevity of the transmission. Like others have mentioned, the synchros take up the slack until they get worn out. I could always tell when a "trucker" came in with a grinding transmission after just a few thousand miles of use that he had been playing "lets float the gears!" They always were bragging about their skill in shifting the transmission so "smoothly" .
Most all professional truckers use the clutch, especially if their split shifting. That is why all big transmissions have a "clutch brake" which acts like a input shaft brake, built in. It's job is to help slow down the input shaft when the clutch is depressed to help in shifting.
I've never seen a professional racer "float gears". They "always" use the clutch. Why ? Because they know it will tear the crap out of their transmission, that's why.
I've only done this myself under duress. Like the time my Deuce in the Marines got a jammed-up clutch and would not release. I was twenty miles out in the desert with a platoon of explosive trainees. I was hot, tired and extremely hungry and in desperate need of a shower, so I was determined to make it back to base come Hell or High water. That is when you can "float your gears" .

 

[INFChief]

I have put a vehicle in N prior to stopping but just prior to stopping and going nearly zero miles an hour. I’ve also done it on a flat stretch with no traffic - but as stated it might be problematic to take a gear if the tranny & drive train are at different speeds.

 

[HDN]

I have put a vehicle in N prior to stopping but just prior to stopping and going nearly zero miles an hour.

That's what I do with a manual, or else you stall out

 

[INFChief]

That's what I do with a manual, or else you stall out

You will stall out with it in gear & the clutch pedal pushed in?

 

[HDN]

You will stall out with it in gear & the clutch pedal pushed in?

I guess only if the clutch is broke?

The way you described it read like how everyone should stop a vehicle with a manual transmission, or at least how I do it:

1. Downshift to appropriate gear when anticipating stop to engine brake - use service brakes as needed
2. When approaching engine idle speed, press in clutch and use service brakes the rest of the way to a stop

Having written it that way, I don't technically leave it in gear all the way to a stop. In my old Wrangler, I'd downshift to 3rd to engine brake, then press the clutch in when I get around the engine's idle speed. By that point I can stop safely with service brakes. In my dad's M37 or halftrack, I'd downshift to 3rd as well and do the same thing. Even with my M35A3 or my wife's 1-ton Savana I put the automatic in 3rd to engine brake.

I think it helps with these vehicles being geared as they are that they can engine brake pretty easily without having to downshift far. Though the 1-ton Savana's 4L80-E can be flipped to 2nd around 40 MPH for more engine braking power.

 

[NDT]

On a heavily laden deuce or on a start on a grade, I put the main transmission in second and drop the transfer to low. Next shift is transfer to high, then 3-4-5 in high. Works best for me.

 

[ToddJK]

I will say, I always use the clutch and I always start in first gear on flat or uphill grades. 2nd if I'm on a downhill grade or slowly moving. I've never double clutched up or down and I only downshift once I'm about 5 mph or more under the max speed for that gear. Your transmission kinda talks to ya, too high of speed and you'll hear a whining noise while attempting to put it in the lower gear. I don't granny shift or shift lightly, once that clutch is depressed, I forcibly put it into gear, not man handle it, but whenever I've done it slowly and lightly, it almost feels like it kinda fights me a little and sometimes a little grinding, but it never does that when I do with intention and sometimes some profane insults, the deuce has been the only vehicle I've ever known to respond positively from negative profane insults .