Horsepower

[AH64-longbow]

I recently purchased a M928A2 it's here in Papua New Guinea, question?, I have driven 300 miles from the Port city to the central Highlands. Three large mountains, 8, 9000, ft. Vehicle was empty, eng is fresh but eng power dropped quick approaching grades, rpms were up, accelerator to the floor, Auto gearbox, dropped to 1st gear, flat run no issues runs flat out, 55, 60 mph. I bought to carry loads, cargo up to ten tons but now I am very concerned the vehicle just won't be able to muscle wise! Great vehicle but am I missing something here? I had a 72 M35A2 in Central Africa for, 20 yrs. Good vehicle no complaints. Any suggestions

 

[NDT]

Yup the Army hated these trucks because of that reason they have no azz at all, the tractors with a loaded tank trailer were ridiculous slow up hill.

 

[Ajax MD]

Yup the Army hated these trucks because of that reason they have no azz at all, the tractors with a loaded tank trailer were ridiculous slow up hill.

The engine in the A2 weighs like, 1/2 of the NHC-250 and has the same power. Didn't this help the situation at all?

 

[USAFSS-ColdWarrior]

I recently purchased a M928A2 it's here in Papua New Guinea, question?, I have driven 300 miles from the Port city to the central Highlands. Three large mountains, 8, 9000, ft. Vehicle was empty, eng is fresh but eng power dropped quick approaching grades, rpms were up, accelerator to the floor, Auto gearbox, dropped to 1st gear, flat run no issues runs flat out, 55, 60 mph. I bought to carry loads, cargo up to ten tons but now I am very concerned the vehicle just won't be able to muscle wise! Great vehicle but am I missing something here? I had a 72 M35A2 in Central Africa for, 20 yrs. Good vehicle no complaints. Any suggestions

I see this is your first post!

Welcome aboard

Find a bunk, stow your gear, and prepare to get underway

Others with "expertise" in the M9xx series trucks are already chiming in. You've joined a good group of folks here.

Again, WELCOME!

 

[98G]

The engine in the A2 weighs like, 1/2 of the NHC-250 and has the same power. Didn't this help the situation at all?

Not at all.

It doesn't have quite the same power either. The 8.3 actually makes a bit more torque and a bit less horsepower. Thing is, it makes its power later in the rpm range. My experience is the 8.3 will hold speed better if you hit a hill already at speed, but taking off on a hill or accelerating from a stop the NH250 does better, especially fully loaded.

Mentioning these facts usually results in the "my engine is better" argument. I've owned multiple examples of both. I currently own both.

 

[162tcat]

Since it’s an A2 with the 8.3, bump the power up. Search on here, lots of info on it. If you turn up RPM and power it will be a complete different truck.


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[AH64-longbow]

Since it’s an A2 with the 8.3, bump the power up. Search on here, lots of info on it. If you turn up RPM and power it will be a complete different truck. Sent from my iPhone using Tapatalk

Ok understood, someone else told me hope to increase the horsepower by adjusting the fuel input via the fuel injection pump? So I can follow that, on the increase of RPM, this is done at the injection pump too?

 

[98G]

Caution is warranted when turning up the fuel. Doing so means the engine is no longer idiot-proof. It becomes easy to melt the pistons, most especially on long steep hills with a load.

 

[Elijah95]

Egt and boost gauge followed by maxing out the injection pump main fuel, bump timing to 15° and intercooler install get rid of the aftercooler then it’s idiot proof again


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[Jbulach]

Except the transmission...

Running hills that pull you down to first gear, watch your transmission temps at 40,000lb+ gross weight. You may have to go down to low range with the transfercase if your hills and road conditions are as bad as I suspect. Also don’t lug the engine, keep it cranking up above 1,700rpm while under load.

If they can get traction, these trucks stock will carry 10ton up just about every hill you can point them at, just not fast. Unless spare parts are easy to procure and install down there, put a pyrometer and 3k governor springs in it, and go conservative with any fuel increase.

 

[AH64-longbow]

Except the transmission...

Running hills that pull you down to first gear, watch your transmission temps at 40,000lb+ gross weight. You may have to go down to low range with the transfercase if your hills and road conditions are as bad as I suspect. Also don’t lug the engine, keep it cranking up above 1,700rpm while under load.

If they can get traction, these trucks stock will carry 10ton up just about every hill you can point them at, just not fast. Unless spare parts are easy to procure and install down there, put a pyrometer and 3k governor springs in it, and go conservative with any fuel increase.

Firstly, I would like to thank all of you who have given advice. I don’t take it lightly. I am 58 yrs old, spent time with the 101st, and been in Africa for 20 yrs. Here in PNG, roads are torture on a vehicle, broken springs, chassis etc. Are common. The mountains are not gradual, but direct corners are not long but short, & sharp. I have four mountain passes ranging 8, to 10,000 feet. Most of the roads are gravel, dirt, some tarred. Potholes and riveted. I am not trying to win a race but I do need the truck to pull the mountain with a load. Genuine spares I will have to order from the US, thus (down-time, cost, etc) I do mechanical work but am NOT a professional mechanic. I need the truck to last, so from reading some of the comments, I am not sure I should tap into this fuel (adjust) as it appears there is more to it than just turning some nuts etc... if I had some of you chaps here to help me, with the tuning maybe I would feel more comfortable. I don’t want a fresh eng having burned pistons because I defaulted on tuning.
This brings me to another question, the placard in cab, and operational manual says shifting of transfer case is to be done with main gearbox in Neutral, so what do I do when I need more power and have already started my accent on one of these mountains /w a load, it’s not logical to stop, shift to neutral engage low gear and carry on! Another question, manual says whilst in low range six wheel is engaged (front axle) is this not going to cause issue on a non-slippery surface such as tarmac? Pls advise, thank you.

 

[simp5782]

Start by closing the aneroid valve. Top of the pump. There is a plug that will need a allenhead socket. Remove it. there is a little ring in there with notches on it. small screwdriver and pry it so you turn it to the inside. As many clicks as it will go. Then drive

 

[162tcat]

You can turn up the RPMs without turning up the power. That makes a pretty big difference too. If you do get stuck pulling in first gear at least you’ll have a little more speed.

If you’re going on familiar roads and you know they are very steep, I’d just start in low range. You will likely lose all of your speed trying to shift on the fly from high to low and you’ll end up starting all over again. Best just to pick the right range before the hill.

As far as the 6wd if you do a search for that on here there is a washer you can remove so than 6wd is only activated by the switch on the dash. Then you can have low range without the front axle being locked in.


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[AH64-longbow]

You can turn up the RPMs without turning up the power. That makes a pretty big difference too. If you do get stuck pulling in first gear at least you’ll have a little more speed.

If you’re going on familiar roads and you know they are very steep, I’d just start in low range. You will likely lose all of your speed trying to shift on the fly from high to low and you’ll end up starting all over again. Best just to pick the right range before the hill.

As far as the 6wd if you do a search for that on here there is a washer you can remove so than 6wd is only activated by the switch on the dash. Then you can have low range without the front axle being locked in.


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I have a concern, forgive the many queries, you might think I have never driven one of these trucks or know nothing about mechanics, however the last vehicle M35A2 I could shift the transfer case from low to high or vice versa (within speed range), it was standard shift, the 928A2 I have (auto-trans) as many of you writers already know, the placard in cab states...( main gearbox in N, shift transfer case by depressing button (air) on end of stick). I have tried shifting whilst non moving and there seems to be a very difficult almost stubborn stall when trying to engage the low ratio, or from low to high. I usually have to try several attempts and shifting main gearbox in and out of drive, or reverse until it engages.
Somewhere, I know this is not normal and I asked the supplier advice on this, reply was ( try releasing air from the tanks) ok, but why? And how would I do this with a load and attempting to go up a steep grade? Just doesn’t make sense.
I agree with the last post, it’s better to be in the right gear before attempting the climb. Any suggestions would be appreciated.

 

[AH64-longbow]

G’day from downunder,
I was on here a few months ago, I have recently popped out a rear- torque rod/arm from the rear-most axle, truck empty, however reversing in low gear on muddy mountains to make a turn, yes I know the manual and placard in-can say DO NOT reverse in low range, (reasons are not given) axle shifted, spring set slipped out of alignment slot. I stopped in time, no damage to truck, realigned, fitted back torque arm and secured with spare rubber tubing and paracord. Driveable, BUT not safe. Queries, can these rubber bushings be bought and installed as such or does one need to purchase the entire arm with rubber bushings installed complete? That is my first question?
2. Secondly, what do I now do about my physical issue with mountain roads, corners, and popping out torque arms? Not always can I just drive or reverse straight or in high ratio. Please advise and thank you

 

[98G]

G’day from downunder,
I was on here a few months ago, I have recently popped out a rear- torque rod/arm from the rear-most axle, truck empty, however reversing in low gear on muddy mountains to make a turn, yes I know the manual and placard in-can say DO NOT reverse in low range, (reasons are not given) axle shifted, spring set slipped out of alignment slot. I stopped in time, no damage to truck, realigned, fitted back torque arm and secured with spare rubber tubing and paracord. Driveable, BUT not safe. Queries, can these rubber bushings be bought and installed as such or does one need to purchase the entire arm with rubber bushings installed complete? That is my first question?
2. Secondly, what do I now do about my physical issue with mountain roads, corners, and popping out torque arms? Not always can I just drive or reverse straight or in high ratio. Please advise and thank you

Low range reverse is prone to splitting the transfer case. Shift to high range prior to backing or plan to replace the t case.

 

[Floridianson]

Caution is warranted when turning up the fuel. Doing so means the engine is no longer idiot-proof. It becomes easy to melt the pistons, most especially on long steep hills with a load.

Agree, Wrong truck for the job do not mess with the fuel / injection pump. Myself yea I would have gone with mechanical injection, at least 400 hp with Jake brake and manual transmission plus Hendrickson suspension. Also non military but something that parts a readily available.

 

[Jbulach]

G’day from downunder,
I was on here a few months ago, I have recently popped out a rear- torque rod/arm from the rear-most axle, truck empty, however reversing in low gear on muddy mountains to make a turn, yes I know the manual and placard in-can say DO NOT reverse in low range, (reasons are not given) axle shifted, spring set slipped out of alignment slot. I stopped in time, no damage to truck, realigned, fitted back torque arm and secured with spare rubber tubing and paracord. Driveable, BUT not safe. Queries, can these rubber bushings be bought and installed as such or does one need to purchase the entire arm with rubber bushings installed complete? That is my first question?
2. Secondly, what do I now do about my physical issue with mountain roads, corners, and popping out torque arms? Not always can I just drive or reverse straight or in high ratio. Please advise and thank you

I think with a little patience and maintenance, you have the perfect truck for the job!

You can buy and press just the bushings in yourself, and you might as well replace them all and hopefully not worry about them for another 20 years. There is a good thread on the replacement here, but I can’t link it from my phone.

They can readily be found for a decent price in the US, on ebay, most of the military parts equipment dealers, or even Amazon. However Eastern Surplus may be your best bet for international shipping, but their prices tend to be higher to start with.

As for backing up in low range I do it all the time, but I am the only operator, and very cautious on load and throttle application while doing it. I also disabled the auto front axle engagement while in low range, as it has been debated that it lessens the strain on the transfer case, as well as making the truck turn better while driving low range on hard surfaces.

How is the truck working out otherwise? Would love to see some pictures or video of it working on the roads of PNG!

 

[Floridianson]

Steep mountains high altitudes my .02 still wrong truck. Any problem with the transfer case or automatic transmission over heating you out of luck. At least with a manual transmission you could come down off a mountain in a low gear and not burn up or loose your brakes using the engine with or without Jake brake together. Plus make it to where you need to go. With a % of HP loss at higher altitudes it pays to start with higher stock HP to begin with. My next choice manual trans. computer control engine with MAP and once again high HP/ Tq.

 

[Jbulach]

Yes, if he wants to build a truck that all would be nice, especially a stronger transfercase, manual trans, and an engine brake or retarder.