Horsepower

[USAFSS-ColdWarrior]

yes I know the manual and placard in-can say DO NOT reverse in low range, (reasons are not given)

You are correct. There is no reason the 18 year old, 120 lb. Private needs to know "why not".... It's a stated in his ORDERS, he is to follow them or face the consequences.
Kinda the same thing here.... even when the MV is released into the civilian world.... VIOLATE the operating instructions and don't be surprised if something goes wrong... sometimes even HORRIBLY WRONG ! ! !

 

[AH64-longbow]

Thank you indeed for your reply and advice , I have a couple mates in the US who can source these parts and will get them to me, I do mechanical work, (not a professional) but am able. The truck does great here, I expected a bit more high end horsepower but it’s not there, the gearing yes. How do I get pics and videos posted directly to you or on here? And any word on the mechanical reasons why the low-range reverse pops out the torque rods and or (will split) transfer case as one chap put it? I am the only driver and I am very cautious with my vehicles no cowboys in my camp!

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.View attachment 803297

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!

e

 

[AH64-longbow]

G

You are correct. There is no reason the 18 year old, 120 lb. Private needs to know "why not".... It's a stated in his ORDERS, he is to follow them or face the consequences.
Kinda the same thing here.... even when the MV is released into the civilian world.... VIOLATE the operating instructions and don't be surprised if something goes wrong... sometimes even HORRIBLY WRONG ! ! !

Got it thank you!!

 

[Floridianson]

What size tires are you running?

 

[AH64-longbow]

What size tires are you running?

I bought the truck with Super singles fitted the Michelin

 

[Lukes_deuce]

I will give you my 2 cents. I dont have the elevation you have, which will rob horsepower from any engine but I do have plenty of experience is some bad terrain. I usually have 4000 to 5000 pounds on the truck while off roading. I have been through 4 foot of water, 4 foot of mud, been stuck up to the bumpers and through some nasty gullies & ravines.

As for the dog bones. I would buy new replacement bushings from a reputable dealer. My suggestion is Eriks suprlus or Big Mikes. There are others. Then once installed, weld on flat stock, rebar or some type of 1/4 thick metal to act as a safety bar. Also dont forget to install cotter pins.

For your lack of power issue, it depends on how fast you want to traverse these 9000ft mountains. If it were my truck, I would put it in low and leave it in 2-1. Carrying 20,000 pounds up and down mountains will be taxing. You have a 928, which is on the heavier side already. Add 20k and your in the mid 40k range. That will make for long days. I have turned the pump up on mine and it does help but its not a huge difference in low range and slow speeds. I would suggest 3k governor springs and a little fuel increase. Also install gauges. The added power helps when on the highway going up hills. You need to use gearing in this situation. I highly suggestion hitting the hill at 2100RPM.

For low range in reverse. I have backed up countless times in low range reverse while off roading. I always disengage the front axle and take it easy. I havent had any problems in 5 years of ownership. Knock on wood. I have heard horror stories and seen the pictures of carnage. Ive also seen some guys put their trucks through some nasty situations in low range and have had no issues. It sounds like you know how to operate these trucks and know how to drive. Use your best judgement and know that theres always a chance. Maybe while navigating a switch back, you put it in neutral and roll back in stead of reverse. Most of the time you do not need a lot of throttle while in low range reverse. The smaller tires help your ratio overall as well.

 

[AH64-longbow]

I will give you my 2 cents. I dont have the elevation you have, which will rob horsepower from any engine but I do have plenty of experience is some bad terrain. I usually have 4000 to 5000 pounds on the truck while off roading. I have been through 4 foot of water, 4 foot of mud, been stuck up to the bumpers and through some nasty gullies & ravines.

As for the dog bones. I would buy new replacement bushings from a reputable dealer. My suggestion is Eriks suprlus or Big Mikes. There are others. Then once installed, weld on flat stock, rebar or some type of 1/4 thick metal to act as a safety bar. Also dont forget to install cotter pins.

For your lack of power issue, it depends on how fast you want to traverse these 9000ft mountains. If it were my truck, I would put it in low and leave it in 2-1. Carrying 20,000 pounds up and down mountains will be taxing. You have a 928, which is on the heavier side already. Add 20k and your in the mid 40k range. That will make for long days. I have turned the pump up on mine and it does help but its not a huge difference in low range and slow speeds. I would suggest 3k governor springs and a little fuel increase. Also install gauges. The added power helps when on the highway going up hills. You need to use gearing in this situation. I highly suggestion hitting the hill at 2100RPM.

For low range in reverse. I have backed up countless times in low range reverse while off roading. I always disengage the front axle and take it easy. I havent had any problems in 5 years of ownership. Knock on wood. I have heard horror stories and seen the pictures of carnage. Ive also seen some guys put their trucks through some nasty situations in low range and have had no issues. It sounds like you know how to operate these trucks and know how to drive. Use your best judgement and know that theres always a chance. Maybe while navigating a switch back, you put it in neutral and roll back in stead of reverse. Most of the time you do not need a lot of throttle while in low range reverse. The smaller tires help your ratio overall as well.

Firstly, thank you indeed for your (advice and expertise) I take not lightly what you have said. I am not a cowboy, do my own mechanical repairs, am a professional welder (served in 101at Airborne) flew the AH64-Longbow so I am familiar with protocol. I also know a machine has to perform beyond its scope of textbook ops. (As we say in the bush) what can it do?
I would like to know how or at least what words to use to search for how to disengage auto-lock on

 

[AH64-longbow]

Firstly, thank you indeed for your (advice and expertise) I take not lightly what you have said. I am not a cowboy, do my own mechanical repairs, am a professional welder (served in 101at Airborne) flew the AH64-Longbow so I am familiar with protocol. I also know a machine has to perform beyond its scope of textbook ops. (As we say in the bush) what can it do?
I would like to know how or at least what words to use to search for how to disengage auto-lock on

To disengage the auto-lock on front axle when low range is selected. I will need low range to climb these mountains but not the 6X6 engagement.

 

[AH64-longbow]

Firstly, thank you indeed for your (advice and expertise) I take not lightly what you have said. I am not a cowboy, do my own mechanical repairs, am a professional welder (served in 101at Airborne) flew the AH64-Longbow so I am familiar with protocol. I also know a machine has to perform beyond its scope of textbook ops. (As we say in the bush) what can it do?
I would like to know how or at least what words to use to search for how to disengage auto-lock on

Do you traverse the rivers in low range or high? I have not been that deep yet here in PNG but in Africa, I took a M35A2 through a channel (Zambezi river channel) that was 3’ in low range empty)

 

[Jbulach]

To disengage the auto-lock on front axle when low range is selected. I will need low range to climb these mountains but not the 6X6 engagement.

Looks like you figured out the photos, keep them coming!

The torque rod bushings just get old and pop off under stress, I have never heard of transfercase range, or travel direction having a major effect on when they pop, but once one goes the others usually are short to follow. If you have access to a welder, clean the rubber off the end, and weld a washer or something across it to retain the link on the bushing. If you decide to do all of them, use small but hot tacks to get good penetration, but not overheat and damage the bond of the rubber to steel inside the joint.

On the front axle auto engagement.

Some people remove the washer, or eliminate the switch altogether. I just cut the side of the washer off with an angle grinder and wafer wheel. That way if I want to go back to normal operation I can just rotate the washer to engage the switch.

 

[Jbulach]

Good read on transfer case breakage theories.



I almost stalled my transmission completely out, 1rst gear, low range, wide open throtle, dragging my 25 ton loader up out of a mud hole with a thrown track and fortunatly did not break mine.

 

[AH64-longbow]

Good read on transfer case breakage theories.

View attachment 803588

I almost stalled my transmission completely out, 1rst gear, low range, wide open throtle, dragging my 25 ton loader up out of a mud hole with a thrown track and fortunatly did not break mine.View attachment 803593View attachment 803592

Thank you for the pics, it helps me also to read, hear and learn from ‘others’ experiences and success stories like all of us. No one chap has it all locked in. Thank you again! Cheers.

 

[AH64-longbow]

Agai

Looks like you figured out the photos, keep them coming!

The torque rod bushings just get old and pop off under stress, I have never heard of transfercase range, or travel direction having a major effect on when they pop, but once one goes the others usually are short to follow. If you have access to a welder, clean the rubber off the end, and weld a washer or something across it to retain the link on the bushing. If you decide to do all of them, use small but hot tacks to get good penetration, but not overheat and damage the bond of the rubber to steel inside the joint.

On the front axle auto engagement.
View attachment 803587
Some people remove the washer, or eliminate the switch altogether. I just cut the side of the washer off with an angle grinder and wafer wheel. That way if I want to go back to normal operation I can just rotate the washer to engage the switch.

Again thank you for taking the time to help, and showing (pic) this helps tremendously, I will let you know how it goes. Cheers mate

 

[AH64-longbow]

It has been some days since I was on here, I come with some questions for those more knowledgeable than I, recently I made a trip out on some very rugged roads, without a heavy load, tyres were deflated to 50 psi, this helped, but 202 miles took me 14 hrs. The roads are like driving down a river bed without the water. Somewhere I sustained a broken front U-bolt (right- side front) a nut broken off, I suspect a large rock? My guess, question is.. why would the front (right) passenger side steering hydraulic arm snap right at the threaded end ? Anyone’s guess? Yes the roads are rough but other heavy trucks travel these roads too, heavily laden. I was in H-ratio and mostly 1,2,3 gearing with average speeds of 10 mph.
I will try to attach pics.
Second question... why would my primary air pressure drop radically to 10 psi after coming to a full stop descending a mountain with about a 20% grade. I kept speeds within recommended gear- to speed ratio; however it is NOT possible to allow the truck with its own gearing to control speed, air- brake pressure is a must! I personally thing the engineers of any machine/ truck with the dry weight of the 900 series should go back to the drawing board (no engine brake) Really!
The brake drums were really hot, I lost all air pressure so engine switched off and I let things cool down, than restarted and air systems were normal and air pressure regained. Completed my course and arrived home.

 

[AH64-longbow]

Along the journey mountains are 7000 to just over 9800 , grades on most are 30%

 

[NY Tom]

My best guess as to why it broke there is that when the thread was machined it leaves a sharp transition and a potential stress/fracture point.

 

[silverstate55]

I assume you didn’t buy your truck brand-new from the manufacturer, so it is 30-35 years old already. Even if it was supposedly “rebuilt” by a government contractor, many items that don’t appear to be needing replacement will be left on the chassis during the “rebuild.” There are numerous stories about these post-rebuild shenanigans from civilian owners on this site.

I know time is something you don’t have much of, so I’ll keep this short. The torque rod bushings, like Jbulach touched upon, are likely as old as the truck itself and are in need of replacement....their function has nothing to do with any transmission/transfer case performance. The rubber ages and deteriorates and must be replaced after time, which usually manifests itself while the suspension is articulating/twisting. If you have to replace one, you are better off replacing all 12 at once...otherwise you’ll be doing all 12 at the worst possible moments, one or two at a time.

These trucks aren’t meant to do anything fast (except get you into trouble), but they’ll get the job done.

 

[Jbulach]

So, with the u-bolt nut broke off, was the axle still secure, or was it shifting around? If moving around I would say that broke the cylinder, if not I would guess just stressed from the road conditions, and finally let go with a large impact to that tire. I’ve always wondered... How big of a difference does it make at the steering wheel with the cylinder disconnected?

10mph average speeds you probably want to run low range, help save your transmission as well as get a little slower going down the steep hills and help utilize what little braking you get from the engine.

With no, or light loads you can usually air down a lot lower than 50psi as well to help from breaking the truck and your spine. Just keep an eye on tire temperature and remember to air up at speed or when heavy.
If your happy with the truck for a base, sounds like it may be time to start gathering parts and modifying to make it your own. I have better braking on my wish list as well. I don’t think a Jake brake was available for the 6ct, but do believe there are exhaust brakes out there, as well as heavier valve springs.


Not sure about your air pressure issue? Hopefully Wes can chime in on that one.

 

[Lukes_deuce]

It has been some days since I was on here, I come with some questions for those more knowledgeable than I, recently I made a trip out on some very rugged roads, without a heavy load, tyres were deflated to 50 psi, this helped, but 202 miles took me 14 hrs. The roads are like driving down a river bed without the water. Somewhere I sustained a broken front U-bolt (right- side front) a nut broken off, I suspect a large rock? My guess, question is.. why would the front (right) passenger side steering hydraulic arm snap right at the threaded end ? Anyone’s guess? Yes the roads are rough but other heavy trucks travel these roads too, heavily laden. I was in H-ratio and mostly 1,2,3 gearing with average speeds of 10 mph.
I will try to attach pics.
Second question... why would my primary air pressure drop radically to 10 psi after coming to a full stop descending a mountain with about a 20% grade. I kept speeds within recommended gear- to speed ratio; however it is NOT possible to allow the truck with its own gearing to control speed, air- brake pressure is a must! I personally thing the engineers of any machine/ truck with the dry weight of the 900 series should go back to the drawing board (no engine brake) Really!
The brake drums were really hot, I lost all air pressure so engine switched off and I let things cool down, than restarted and air systems were normal and air pressure regained. Completed my course and arrived home.View attachment 808773View attachment 808774

I would deflate down to 25 psi with no load or light load. The 395s are stiff. I run my 923a2 with 53s at 25psi to 20psi weighing in at 26000 off road.

Ive seen U bolts break from excessive movement on an axle. Some trucks have U bolts with rather long threads sticking down and can catch rocks or other high obstacles. You can cut the excessive tread. If your in that type of terrain, you should be in low range. You can get new U bolts made at a truck suspension shop.

As far as the hydraulic ram goes, it looks like a stress fracture to me. Looking at the picture of the snapped end, you can see the crack. Could of been bad for a long time and when you hit the rock to knock the U bolt it could of forced the steering ram backwards and snapped it. Avoids those big rocks!

Low range does help with engine braking and will help slow you down more, which sounds like what you need. I ran the same trails as other 939s and I usually dont need to be on the brakes while the other trucks are in high range and ride the brakes going down a slope.

If you air pressure is radically falling, you either have a leak or you are pumping the brakes to much. On down slopes, you need to hit the brake pedal and hold it enough to give you the needed braking. Do not pump the brakes or you will loose pressure quickly. The air compressors are not great on these trucks.

As far as additional engine braking, there was never a Jake brake or compression brake made for the 6CT. It doesnt have the components needed in the head. Options would be an exhaust brake or a retarder. Engine brakes wouldnt work off road with the truck idling. Im not sure if a retarder would work in this scenario.

 

[Steelreaper80]

It has been some days since I was on here, I come with some questions for those more knowledgeable than I, recently I made a trip out on some very rugged roads, without a heavy load, tyres were deflated to 50 psi, this helped, but 202 miles took me 14 hrs. The roads are like driving down a river bed without the water. Somewhere I sustained a broken front U-bolt (right- side front) a nut broken off, I suspect a large rock? My guess, question is.. why would the front (right) passenger side steering hydraulic arm snap right at the threaded end ? Anyone’s guess? Yes the roads are rough but other heavy trucks travel these roads too, heavily laden. I was in H-ratio and mostly 1,2,3 gearing with average speeds of 10 mph.
I will try to attach pics.
Second question... why would my primary air pressure drop radically to 10 psi after coming to a full stop descending a mountain with about a 20% grade. I kept speeds within recommended gear- to speed ratio; however it is NOT possible to allow the truck with its own gearing to control speed, air- brake pressure is a must! I personally thing the engineers of any machine/ truck with the dry weight of the 900 series should go back to the drawing board (no engine brake) Really!
The brake drums were really hot, I lost all air pressure so engine switched off and I let things cool down, than restarted and air systems were normal and air pressure regained. Completed my course and arrived home.View attachment 808773View attachment 808774

I was fully loaded coming down a mountain north of Atlanta Georgia pulling a non-fuctional backhoe, and a LOT of cargo. Put it down to low range in first gear. The truck would basically brake itself. I rarely had to touch the actual brakes. I included a video of me going up an 18-20% grade at full throttle in first gear. Large amount of tire slip. It took a truck this big to get this stuff off the mountain. Now I know why it stayed up there until I picked it up!