3rd Gear High Or 5th Gear Lo

[Josh]

I've been wondering for a while and didnt see anything that adressed this issue. When yall are stuck going up a hill in the 20-25mph range, do you guys use 3rd High or 5th lo? If I'm loaded I'm normally in 5th LO, but empty I'll keep it in 3rd high.

What do you guys do, and is there any pros/cons of using one over the other?

 

[hoop]

Same as you.

 

[jwaller]

with the transfer in L I would think that you get better pull with that ratio.

 

[jatonka]

hey, whatever keeps the RPMs over 1500 works for me. as far as splitting, and I have a lot of years experience splitting 5x4 twin sticks, the only split I make in M35A2 multifuel trucks, is 4th low to 3rd high. In other words, on a hard pull or heavy load, 2nd low, 3rd low, 4th low, 3rd high, 4th high, 5th high. JT out

 

[Jake0147]

When you're in the "overlap zone", the truck really doesn't care. If I'm going up through the gears, I usually start in low range, work up to five, then flip the transfer up (and the main to four) for the next upshift. If I'm loosing gears, it usually works out best to leave the transfer in high and backshift the main transmission. Of course if you know what's up ahead, like the hill getting steeper, or cresting the hill, traffic, etc then you can plan ahead and choose whatever range will give the best gear selection, both in terms of available speeds and subsequent shifting requirements.
Again, the truck doesn't care, so the answer is whatever works for you. I find that for me, the gear selection in low range is much more convenient at low speed. and use that frequently for "in town" speeds, whether I ask it (with the throttle) for hill climbing power or not.

 

[wreckerman893]

If I am loaded on a steep hill (or a long pull) I find that it is best to use low range and find a gear it will pull in at about 2000 RPM......the engine is not wound out and screaming and you can pull without lugging. Just my preference.

 

[Josh]

Also on one of those long hills, that I know I wont be pulling 4th in, Ill set my hand throttle to keep the truck at around 22mph. Since my tact doesnt work, not exactly sure what RPM it is, But it doesnt sound like its screaming its head off.

 

[shootiniron]

This is prolly a dumb question,no laughing please,but can you alternate between hi and lo in trans case while driving?

 

[Capt.Marion]

This is prolly a dumb question,no laughing please,but can you alternate between hi and lo in trans case while driving?

Search for "split shifting."

To answer your question, yes, as the transfer case is fully synchronised.

To the OP, it depends on whether I was already in high range or in low range when I get to the hill. Usually I'm already in high range, so I hang out in 3H for the bigger grades.

 

[wreckerman893]

This is prolly a dumb question,no laughing please,but can you alternate between hi and lo in trans case while driving?

Split shifting is a learned art......most people only split going up...then slow almost to a stop when dropping back into low range.....if you split when down shifting you have to make dam sure you don't drop into low range with the main transmission in too low of a gear....otherwise you can overspeed the engine and chance destroying it. There is a data plate on the dash that will tell you what speed matches which gear and range.

The only way to get proficient at splitting is to practice, practice, practice.

 

[fasttruck]

WHEN loaded: 2l, 3l, 4l, 5l, 4h, 5h and back down the same way. Always back up on low to save clutch. This progressionj fills in to an extent the jump from 3h to 4h that occurs when running in hgih range exclusively. always upshift first then downshift second. Swing the sticks baby.

 

[rlwm211]

I generally prefer to split from low to high 5th low to 4th high. I miss the huge gap in the gearing between 3rd and 4th in high range which as we all know is a killer under load and climbing a hill.

Splitting going up is easy. Going down is a practised art. I am still acquiring my chops for the downshift in the deuce

I would add that I believe that by thinking ahead when you are driving any heavy vehicle, empty deuce included, you can avoid some situations and then there are those you can do nothing about and have to grind it out. I agree about the rpm goal of not ever exceeding 2200 under a steady load. I have found that the peak of the torque curve appears to be at 1900-1950 rpm. Once you start dropping below that you should be getting ready for a downshift.

Patience is the greatest virtue that you can possess when you are at the wheel and it is even more important in a non power steering, low powered truck such as a deuce.

Just my two cents.
RL

 

[Barrman]

I agree that the truck doesn't care which one you use. I will also say that being stuck on a long slope with a big load in 3rd hi. Means you are really stuck in that gear since going up isn't going to happen and going down is going to be right at red line.

I prefer to work down to low 4th. That way the truck will still climb and if the hill levels off some, I can grab low 5th for that extra 2 mph before the hill slows me down again.

I can think of two stretches of interstate where this is needed. Southbound on I-35 climbing the Arbuckle mountians in OK around mile marker 35 and East bound on I-10 between Ft. Stockton and Sonora. Both are multi mile climbs that level out just enough to make you think going from 3rd high to 4th high is doable, but it isn't.

I got stuck on the I-35 one flat towing another M35 in 3rd hi. 12 mph on the Interstate for several miles is not fun. I hit the I-10 climb in a M109 pushing a strong head wind, outside air temps above 100° and thought ahead enough to get into low. 20 some odd mph and no strain on the truck.

 

[Wildchild467]

if i have a big load on the back ( only happened a couple times), ill start at the bottom of the hill on low range and just take my time going up the hill. I split shift the t-case sometimes and its only going from low to high, but i still dont know how they work inside and it makes me nervous like ill break something. if i have a big load on the back, i have no problem taking my time if it means saving synchros in the t-case or lugging an engine. soon as i get behind the wheel i know its gonna be a slow drive anyway

 

[armytruck63]

I live at the base of some impressive mountain grades. I like using 5th low to climb the grades because I will usually make it to the top in that gear.

If I have to downshift further, 4th low is closer to 5th low than 2nd high is to 3rd high. In other words, if you're in 5th low and have to downshift, your next lower gear is closer than if you're in 3rd high and have to downshift.

I wait until I'm sure the grade has flattened out enough to shift from 5th low to 4th high. It helps to be familiar with your local roads.

You know you're a deuce driver when you tell your wife "This looks like a low range hill for the Army truck." When she tells this to you, you know you have her trained well.