Argo HDI-True eight wheel drive?

[jpswift1]

I have to disagree with some of the statements above. Firstly, the differential steering Argo has used for ever does produce unexpected turns. For example, when you are in high gear and you try to turn gently to follow a slight curve in a trail, while jerking away on the brake if you over do it the thing will shoot off sideways sending you off the trail. Another time would be when you go over the brow of a steep hill. Right at the point where the machine is pivoting on the centre axles, they have a tendancy to swing around as the diff passes all its torque to the easiest side. I've driven both Argos and T20 fitted machines, and can't say that when in a bog that a T20 has ever produced a dangerous swing in direction because one side lost traction, I thing that is a bit of an exageration! Wet brakes/clutches don't really produce oil contamination problems either, otherwise devices like the auto transmission in you car would be high maintenance items. Wet bands that last for 20 years sure beat overheating dry discs.
The theory behind a triple differential transmission is good in terms of efficient steering etc, but my problem is with the complexity, extra moving parts and added cost of such a unit. The T20 is a simple and effective, lightweight, relatively low maintenance unit that has proven durability. They are not perfect, and do require some skill, but I think the ability for the operator to control the speed of each side independantly is a good feature.
Just my thoughts

Very well put and I totally agree with you AussieMax. Thanks for posting that information. The more we know, the better decisions we can make. This site is all about providing useful information from every different standpoint and having all of these folks that have worked on and driven all of these different machines make this site so valuable to all the AATV fanatics.

[liflod]

From what I am understanding from the above posts, when you brake one side in high range, that side does not stop, it turns at 1/3 the speed of the other side, so it is still pulling you through the hole and not dragging you down. True 8 wheel drive in a turn.

[xrover]

I prefer to just go and ride and learn how to recover my vehicle. Any vehicle will and can get stuck, so knowing more about how to get it out safely is more important to me than getting it stuck an extra 20 yards into the bog. You buy an Argo knowing that speed is compromised. If that's unacceptable to you then an Argo is not your best choice.
But I am interested in the suspension seats!

[Malee]

Aussiemax had a point. My 8X8 gets very taily on steep decents, loose rock etc.. (yep, could slow down but WONT) touch the brake and it snaps sideways 45/90 degrees. If there was a proportion of tourque constantly delivered to the braked side I would expect it to straiten quicker through power transfered to the braked side. Is this similar to the Admiral gearbox

My ideal system would replicate a locked drive whenever no break is applied (like an air locker on diff)

[smog]

I guess when we get a diagram of the workings of the tranny, we can all get our brains around what is happening.

I THINK the centaur got the same transmission (except for the hydrostatic control on the input of the transmission)

[AussieMax]

I'm not certain, but I think the Centaur trans is a Double differential and the Admiral is a triple differential.

[mightymaxIV]

Admiral transmission

Hey everyone, I found this letter on the Argo web site, the attached information clears up and helps me to understand just what the new Admiral transmission does and how it works going down the trail. This is the information I was looking for and now makes me look forward to this transmission and axle system going into a Frontier 6x6 or 8x8. Wow1 How soon Argo? when can I have my Admiral equipped Frontier!


Rich Melon - The Outdoor Quest
Friday, March 19, 2010

Mechanical skid steer machines are cursed by the same system that gives them their incredible maneuverability. Usually, mechanical skid systems only allow turning when brakes are applied to one side. The major drawback for a mechanical skid steer machine has always been the little course corrections while traveling down the road. It has never been the zero radius turns while picking your way through the woods to load a downed moose that caused the problems but instead just those little adjustments that snap load the drive line from the motor through the Transmission and drive chains and finally the bearings. Hydraulic or hydrostatic skid steer systems can smoothly and effortlessly turn in any direction. It does come at a cost; the pumps needed are expensive and heavy. The oil is expensive and the volume needed adds a lot of weight and then the oil needs a cooling system as well. Quickly the weight and costs drive the hydrostatic System out of the range of the Argo target market. Argo engineers took advantage of the research and development available at the home office of Ontario Drive and Gear and came up with a revolutionary transmission that accomplishes much of what the hydrostatic drive system does but mechanically, with-out all the weight, oil, and cost. Dubbed the ADMIRAL the new transmission uses some very complex gearing that includes dual differentials on the output shafts. The transmission is a two speed with High and Low settings. Low gear is the zero radius turn skid steer mode we are all used to. High gear is where all the changes take place. In high gear the power input is split at a 3:1 ratio to the wheels in a turn. In fact the inside wheels can be rotating at 3 miles and hour while the outside turn at 9 mph or any multiple of three. The beauty of this is no more skid steering to make those little course corrections or even major turns; just smooth turns where the machine doesn’t load or bog, it simply and effortlessly turns mostly due to the wheel speed differential. In high gear it isn’t possible to lock up a side of wheels. No zero radius turns but the unit gets around in roughly its own length without all the wear and tear on the brakes and chains. In high gear the Avenger drives like a dream, efficiently turning through 95% of the diving the average machine makes in a day and it is just as fun and comfortable to drive as any UTV. When the going demands precise pinpoint steering a flip of the lever on the dash engages low gear and zero radius turns are available. With the high and low gear settings in the ADMIRAL transmission, Avenger owners can have their cake and eat it too! The HDi is a joy to drive and I quickly didn’t want to put the unit in low gear unless I had to. Skid steering has always been a detriment in bad conditions. Most times if you want to turn out of a bog or hole the track or wheels on the good ground are locked up for the turn and the rotating tires or track are in the junk. Not enough traction and the turn doesn’t take place. Not having to stop the wheels on one side means the Argo goes even better in the swamp and snow, allowing the operator to turn out of soft spots without locking up a side and potentially spinning down. The Admiral transmission makes track use effortless even in tall grass and dry clay where skid steering is an immense load on all the drive train. The transmission’s ability to split and transfer power as required through the twin output differentials makes the machine impossibly surefooted, exiting from water and bog even easier than before. Hill climbing in the snow is a breeze and if you need to turn while climbing you just twist the handles feed in some throttle and power through the turn and up the hill. With the new transmission the Avenger is 40% more efficient with power and you quickly get used to the extra oomph, cracking the throttle and using the wheel speed differential to power through turns. Gone this year are the idler prockets and chains. The ADMIRAL transmission is direct drive with the output shafts driving the first and second axles trough double strand chains. Sprockets and chains from this axle go forward and back driving the other axles. The elimination of the idler sprockets and chains reduces the amount of chain used and required maintenance and improves power efficiency. There is no more tightening of the idlers required and one less piece of chain to loosen and multiply the chain slap through the drive line. Just the stress of the idler chains snapping tight and snap loading the next chain adds significantly to wear and tear and maintenance. Now with less chain and stress, maintenance is reduced by up to 20%.New this year is dual brake systems. Two steering brakes; a big beefy disk and caliper on each side of the transmission. In addition there are two smaller disks and calipers one to each side as well. The smaller brakes are used for the hand brake and making it easier to use efficiently on long hills. Because of the Admiral transmission the steering brakesare stressed so little now on the machine that the brake cooling fan has been removed. It is remarkable how much the difference the brake usage is. The steering brake disks on my 750 HDi have some cosmetic surface rust speckling and the brake pads have hardly engaged often enough to wipe that off. Gone are the days of overheating brakes. Of course if you aren’t using the brakes the machine uses power more efficiently. Brake wear is greatly reduced once again lowering maintenance costs.There are other improvements to the Avenger 750 HDi. Carlisle Tire Company working in conjunction with Argo has designed a new 25 inch tire that looks very similar to the old 22 inch Goodyear Runamuk tire. The Carlisle has the same tread pattern but this is where the similarity ends. The ribs are much deeper giving superior traction in mud and bog and the beefy paddles make this Avenger the fastest swimmer in the fleet.

Year round track use is becoming so prevalent that Argo beefed up the axle system to accommodate. The heavy duty
braced front axle extensions have been a standard for years and now the same bracing is found on the rear axles. Extra heavy duty axle hubs are included to take the stress of lug extensions on all axles along with larger improved bearings. The larger axle bearings, are encased in heavier bearing carriers and triple sealed. Greasing the outside axle bearings has been greatly simplified by holes in the tire rims. Just line up the hole with the grease nipple and insert the grease gun, it doesn’t get any easier and faster than that.

On the dash the new information pod tracks rpm, speed, hours, voltage and an odometer in miles or kilometers as well as showing engine temperature and a host of other information. New design molded plastic for the firewall and floor boards are a breeze to remove and reinstall. Steel tie down loops have been added at the rear receiver hitch and at each
front corner of the bearing extensions.

The final tally on the Avenger 750 HDi is very impressive. The numbers speak loudly; 20% less maintenance, 40% more efficient and 10% faster. For me it is the quality of the ride. Argo has taken direct aim at the upscale UTV market and buyer. Argo improved the ride, handling and speed, injecting a fun side to a machine that built its reputation on hardcore work.

[mightymaxIV]

Is the Argo Admiral transmission True six wheel drive?

Since the introduction of the Admiral transmission every has been asking the same question: Is the Admiral transmission a true six wheel drive transmission.

To answer this question I jacked my 650 HD Argo off the ground on the left side insuring that nothing on the left side was touching the ground.

I then got in the machine started the engine, put the machine in drive and eased on the gas with out any steering input.

So what's the answer?

As I eased on the gas the right side grabbed traction and pushed the machine forward with no steering input what so ever.


So the answer is: The Admiral transmission is truly a six wheel drive transmission!

[mudbug3]

Dan


That was a question I was uncertain about concerning the new Admiral transmission. Thanks for answering this question.

[teddybear894]

It's strange how sometimes the Admiral will act like all wheel drive and other times not eh... I wonder why?

[mudbug3]

It's strange how sometimes the Admiral will act like all wheel drive and other times not eh... I wonder why?

Thats a very good question.

[mightymaxIV]

The Admiral transmission is fussy, sometimes you have to remind it that it's an Admiral, not sure I understand what's going on in those gears.

However: I have seen the same thing in every gear driven limited slip and positive traction unit, they don't always do what they are suppose to do. As a Kid I remember watching drag races and the racers always had to insure their Detroit locker was locked before a race.

I have also watched the lockers and limited slip units on the front end of quads fail to work as advertised on many occasions: I'am not convinced that there is a perfect gear driven system.

About 95% of the time my Admiral works just the way it should.

This is copied from the Argo test above:

" In high gear it isn’t possible to lock up a side of wheels. No zero radius turns but the unit gets around in roughly its own length without all the wear and tear on the brakes and chains."

Hummmmmm not possible to lock up a side of wheels? Hummmmm? What do you say Teddy Bear?

[pcmark]

Dan, I suppose that if the power is split in high gear 3:1 between the two sides at full turn, at a slow enough speed it could be darn close to a true skid steer type lock-up at full turn, simply because the inside wheels would be barely turning -- and I suppose this could most likely occur under extreme load, at very low speed. Have you experienced this? ...I see the 3:1 power split being among the most benefit at higher speeds, where the machine is going to steer inherently smoother than a true skid steer, or for course correction in situations where you can't afford to totally cut one side's power (but, again, the more overall wheel speed that you have, the more logically effective the 3:1 power split should be in many situations). Lastly, you still have a single engine via "mechanical linkages" trying to "simulate" independent drive wheel power (as opposed to various hydrostat or electric vehicles, where a left and right drive wheel can have 100% power independent of the other), so there's going to be something lost in the translation -- or transmission, as it is! What's important to remember, as you point out, is that there is no ideal machine, and while some argue that ODG's Admiral transmission is a very complex way of addressing the steering of "skid steer" vehicles, it's a pretty darn ingenious way of accomplishing it.

[mightymaxIV]

Mark-very true statements:

I have only seen two systems that you can steer in extreme mud without losing drive to one side, the Admiral and hydrostatic, I personally think the Admiral is about as good as you can get in a gear driven steer system.

Heres what I know for sure, the Admiral works for me and has performed better under extreme conditions then anything I have seen short of a full hydrostatic Mudd Ox.

Pertaining to your question about heavy loads: Having watched my own videos of my machine in extreme mud at Big Nasty and other ATV parks I personally have yet to see a time when the machine lost drive, it seems that that transmission is constantly putting drive to both sides and that in and of itself is an amazing thing, the exception is when a track is completely off the ground it will spin faster than the loaded side, under this circumstance you have to help the drive go to the traction side with steering input.

[pcmark]

It could very well be that in high gear, there's some sort of baseline to the Admiral, where if the one side is moving, the other side is governed to never slow to the point of stalling (or that you could pragmatically never drive an Argo at such a slow speed that the 3:1 would equal a virtual stall speed on the inside drive wheels). I guess what intrigues me is the question of whether the 3:1 is infinitely variable to a crawl, or is there some sort of limiting factor -- designed in or indirectly contributing -- that would never allow a slow enough speed to effectively stall the inside wheels (it's really more of a theoretical question)? Where's an ODG engineer when we need one?