Orion: still popping out of gear! Lets form a club!!!
- Thread starter CruiserMax
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I have about 2k miles since the last mods to the Orion. 1 Rubicon trip and 1 Barrett lake trip and some other trails. Lots of steep down hill testing in High and Low range. Tring to get it to pop out. The tranfercase will not come out of gear. I did not have a problem with the old case but I could always get it to pop out by playing the gas pedal. When the Orion was in the 1st time it would come out in High and Low Range very easily. It will not come out of gear now. The washers I made are hardened A-2 tool steel with some oil grooves in them. I feel there is plenty of room for oil to get in there. I saw no reason for .025" clearance. That clearance can allow the gear to walk the collar out of the spring detent. The shift fork can not hold the thrust of the gear a stiffer spring alone will not cure the problem.
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Since I do not have any kind of education in physics or engineering, I'd like to take a step back from the specifics of the Orion and discuss this from a slightly more theoretical viewpoint to see if I am starting from a faulty premise.
In my mind, I picture the difference between a ramped gear and a non ramped gear pushing against the shift collar as being like the difference between a scratch awl and a screwdriver pushing down against a piece of metal. Assuming that both the awl and the screwdriver are aimed at a slightly less than vertical angle at a horizontal metal surface that has no surface imperfections and is polished to a have an extremely low coefficient of friction, both will have a tendency to slide.
The screwdriver will have a tendency to slide sideways, on an axis perpendicular to that of the blade, the surface area of the blade reducing the pounds per square inch of pressure between the blade and the metal surface. The scratch awl will have the ability to kick out in almost any direction away from the vertical because its pressure is not spread out across a broader area.
Now, as soon as that horizontal metal surface acquires an imperfection that both objects are capable of exerting pressure against, it seems to me that the scratch awl will have a much higher likelihood of 'sticking' to what ever imperfection there is in the metal, while the screwdriver blade is less likely to 'catch' the imperfection and be held by it. I hope this analogy makes sense.
Taking this analogy and applying it to the Orion, it would seem to me that at the very initial install stage, neither a ramped tooth or a straight one would have a very good bite on the shift collar. Based on the fact that the non-ramped one would continuously exert a much higher psi of pressure against a smaller area of the shift collar than a ramped one designed to mimic the ramped gear, the non-ramped gear should theoretically 'bite' into the collar sooner, deeper, and in a way that is more likely to keep the gear in contact with the collar in the long run.
Looking a bit further down the road, it would also seem to me that if the hardness of the gear exceeds in any meaningful degree the hardness of the shift collar, that it would impress a straight 'cut' into the collar, eventually making it harder to transition OUT of the gear. Then I guess you'd have to remove your top cover and DECREASE the tension on your shift fork!
From the picture I have in my head now, I see the canting of the gear on the shaft, along with the fore-aft motion as being the major culprit here, and I think that Poser's thrust washers are definitely going to help keep the gear-collar wander down for the time that it will take for the new gears to 'cut' themselves into the collar, at which point there shouldn't be any more popping issues.
In my mind, I picture the difference between a ramped gear and a non ramped gear pushing against the shift collar as being like the difference between a scratch awl and a screwdriver pushing down against a piece of metal. Assuming that both the awl and the screwdriver are aimed at a slightly less than vertical angle at a horizontal metal surface that has no surface imperfections and is polished to a have an extremely low coefficient of friction, both will have a tendency to slide.
The screwdriver will have a tendency to slide sideways, on an axis perpendicular to that of the blade, the surface area of the blade reducing the pounds per square inch of pressure between the blade and the metal surface. The scratch awl will have the ability to kick out in almost any direction away from the vertical because its pressure is not spread out across a broader area.
Now, as soon as that horizontal metal surface acquires an imperfection that both objects are capable of exerting pressure against, it seems to me that the scratch awl will have a much higher likelihood of 'sticking' to what ever imperfection there is in the metal, while the screwdriver blade is less likely to 'catch' the imperfection and be held by it. I hope this analogy makes sense.
Taking this analogy and applying it to the Orion, it would seem to me that at the very initial install stage, neither a ramped tooth or a straight one would have a very good bite on the shift collar. Based on the fact that the non-ramped one would continuously exert a much higher psi of pressure against a smaller area of the shift collar than a ramped one designed to mimic the ramped gear, the non-ramped gear should theoretically 'bite' into the collar sooner, deeper, and in a way that is more likely to keep the gear in contact with the collar in the long run.
Looking a bit further down the road, it would also seem to me that if the hardness of the gear exceeds in any meaningful degree the hardness of the shift collar, that it would impress a straight 'cut' into the collar, eventually making it harder to transition OUT of the gear. Then I guess you'd have to remove your top cover and DECREASE the tension on your shift fork!
From the picture I have in my head now, I see the canting of the gear on the shaft, along with the fore-aft motion as being the major culprit here, and I think that Poser's thrust washers are definitely going to help keep the gear-collar wander down for the time that it will take for the new gears to 'cut' themselves into the collar, at which point there shouldn't be any more popping issues.
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off the sidelines
Finally got enough time together [love those hands-free headsets] to get on the phone with Vic and get one of these cases coming my way!
This should be VERY interesting.
Finally got enough time together [love those hands-free headsets] to get on the phone with Vic and get one of these cases coming my way!
This should be VERY interesting.
65swb45 said:Finally got enough time together [love those hands-free headsets] to get on the phone with Vic and get one of these cases coming my way!
Yours leaving soon? Or waiting for the new shift shaft?
bjowett
Supporting Vendor
End the club...? Perhaps a band-aid. It will be shifting the high low gate on my Orion.
https://forum.ih8mud.com/showthread.php?t=56043
https://forum.ih8mud.com/showthread.php?t=56043
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cruiseroutfit said:
I didn't ask!
Not really worried tho; busy with customer's rigs for the next few weeks as it is.What is the new shift shaft?
Is that a "fix" for the popping out of gear problem?
I want them to get it fixed so I can get mine
Is that a "fix" for the popping out of gear problem?
I want them to get it fixed so I can get mine
just want everyone to know, i am not a member of this club.
orion #255 is installed and hasn't popped out yet. i put my truck in all the common situations and no luck. so, i can't join.
orion #255 is installed and hasn't popped out yet. i put my truck in all the common situations and no luck. so, i can't join.
I think it might be a single or double digit thing.........#41 popping like 
i have a home-made twin stick that is pretty stiff when shifting-that may be helping keep it from popping out.
treerootCO
Where are my keys?!
I have a custom shifter as well....
I call it my passenger
I call it my passenger
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a few washers
Pulled the box off the shelf. Not sure how many more are scattered around the shop, but there were 65 of them in the box. Let the grinding begin!
Pulled the box off the shelf. Not sure how many more are scattered around the shop, but there were 65 of them in the box. Let the grinding begin!
finally got mine to pop out, but i was climbing uphill in 4hi with the pedal to the metal.
i still don't think i can join your club.
i still don't think i can join your club.
1Fine40
Rust Buster
65swb45 said:
Care to share a set of those washers with another club member?? PM me if you are interested. Thanks.
OK… I’ve read this thread pretty intently and its got me pretty concerned. I got kicked over here from the pirate board because I’ve been considering an Orion as part of the powertrain in a Land Rover Series IIA/Defender 110 hybrid buildup that I’m doing. Cummins 4BT/NV4500 powerplant. Short of it being that I need a bulletproof low range T-case with an offset rear.
Dieselcruiserhead and Orangefj45 on the Pirate LC board said I should really ask around here to get an idea of how much of a problem these T-cases are having.
I’m a trained and decently experienced engineer and to me, the straight cut dog splines on these after market gearsets are 100% the problem, as cruiserbrett and treeroot have said. NO DOUBT ABOUT IT. Additional mods may help with a sketchy fix, but ultimately I think that the dog clutch design is flawed. Those gears should want to pull themselves together under load (thus the original factory undercut spline), but with straight splines they are free to walk themselves apart under load or any kind of deflection. Since gearsets operate with high viscosity lube and the teeth are not in theory meant to touch each other, but rather operate on a “cushion” of lube, the tendency for the dog collar and gear to separate from each other is only more exacerbated; without a positive retention force from beveled teeth, even the smallest axial force would tend to separate the two. Detent springs and other techniques with the shift fork may provide a sketchy fix, but in the end that fork was not designed to operate under continuous load, and the detent ball was only meant to secure the shift mechanism from flopping around, not provide the axial locating force for the shift collar. Keep in mind, I have NEVER actually seen one of these cases (or even a LC case) up close; I am just going off ample pictures and experience with transmissions and marine outdrives. Hell, the simplest proof is this – I don’t know about on toy cases, but on my scout dana 300, you CAN’T disengage 4H or 4L when the transfer case is under load… not even close. No amount of pulling on the shifter will get the thing to disengage. Its only when the truck has been driven straight for a bit, the front driveline unloaded, and the clutch disengaged and the truck stopped that you can shift the thing. Any time the T-case is loaded it “pulls itself into gear”, i.e. because of the beveled dog splines.
I’d LOVE to hear that someone has come up with a decent solution to this problem, or that AA is going to issue a suitable fix… but somehow I’m not optimistic. Anyone have any recent input? I really want one of these cases (it meets my needs), but I can’t bring myself to buy a case that is going to chronically (if not dangerously) skip out of gear. There could be serious wear issues too with the dog splines… if the gears keep spitting themselves apart under load, the tendency would be for the splines to wear a positive taper towards the open ends of the splines, making them even MORE prone over time to walk apart.
Bummer. I was really hoping this case would be bombproof. Does anyone know the stats on what % of people are actually experiencing this problem?
Dieselcruiserhead and Orangefj45 on the Pirate LC board said I should really ask around here to get an idea of how much of a problem these T-cases are having.
I’m a trained and decently experienced engineer and to me, the straight cut dog splines on these after market gearsets are 100% the problem, as cruiserbrett and treeroot have said. NO DOUBT ABOUT IT. Additional mods may help with a sketchy fix, but ultimately I think that the dog clutch design is flawed. Those gears should want to pull themselves together under load (thus the original factory undercut spline), but with straight splines they are free to walk themselves apart under load or any kind of deflection. Since gearsets operate with high viscosity lube and the teeth are not in theory meant to touch each other, but rather operate on a “cushion” of lube, the tendency for the dog collar and gear to separate from each other is only more exacerbated; without a positive retention force from beveled teeth, even the smallest axial force would tend to separate the two. Detent springs and other techniques with the shift fork may provide a sketchy fix, but in the end that fork was not designed to operate under continuous load, and the detent ball was only meant to secure the shift mechanism from flopping around, not provide the axial locating force for the shift collar. Keep in mind, I have NEVER actually seen one of these cases (or even a LC case) up close; I am just going off ample pictures and experience with transmissions and marine outdrives. Hell, the simplest proof is this – I don’t know about on toy cases, but on my scout dana 300, you CAN’T disengage 4H or 4L when the transfer case is under load… not even close. No amount of pulling on the shifter will get the thing to disengage. Its only when the truck has been driven straight for a bit, the front driveline unloaded, and the clutch disengaged and the truck stopped that you can shift the thing. Any time the T-case is loaded it “pulls itself into gear”, i.e. because of the beveled dog splines.
I’d LOVE to hear that someone has come up with a decent solution to this problem, or that AA is going to issue a suitable fix… but somehow I’m not optimistic. Anyone have any recent input? I really want one of these cases (it meets my needs), but I can’t bring myself to buy a case that is going to chronically (if not dangerously) skip out of gear. There could be serious wear issues too with the dog splines… if the gears keep spitting themselves apart under load, the tendency would be for the splines to wear a positive taper towards the open ends of the splines, making them even MORE prone over time to walk apart.
Bummer. I was really hoping this case would be bombproof. Does anyone know the stats on what % of people are actually experiencing this problem?
over analyzed it . If the viscous layer theory was working what would the taper do other than hold more fluid.? Put some miles on em and they run fine given all the area's of concern are adressed. These being easy to do and not an inherent problem with tcase design other than the flawed teeth. I to am a believer that the teeth are not right. I example this by the comparison of a sm420 that popped outa 3rd until due to worn dogteeth. Which no longer pops out cause gear was switched to later version with redesigned dogteeth.
But
The teeth thing wears itself in.
The gap between hi and lo gear is the major problem I feel. See Mr. Algazy for washer that compensates for this.
But
The teeth thing wears itself in.
The gap between hi and lo gear is the major problem I feel. See Mr. Algazy for washer that compensates for this.
Well, as long as theres a negative bevel on the dog splines, its just like the helical gear analogy that people have used. Even with a real slick layer of lube between the shift collar and the gear, because of the angle, the tendency is for the torque load transmitted by the collar to the gear to pull the two together… actually moreso with the lube, since it tends to reduce the friction preventing the two from sliding relative to one another to near zero.
Here’s the question that I’m not quite sure of, since I don’t have one of these cases to look at and haven’t built one like you all have. You reuse the original shift collar, correct? For those of you like peesalot that are talking about the gears “wearing in”, what is it that you propose wears into what? You get new gears, so you are saying that the splines on the old shift collar (which are at a factory 2 deg taper) wear a negative angle into the straight cut splines of the new gears? Is that the idea?
Not having the parts on hand, I can’t really get a good idea… but what do the internal splines on the gears look like? How are they cut? Is the bearing ID of the gear in relation to the splines big enough that you could set up some sort of 2 degree jig and give each spline a few strokes of a jewlers file in order to start setting the proper taper? If it could be done, what would you be talking, 50 teeth or something? Nothing that a few hours and some beers couldn’t handle. ASSUMING that the gear was designed such that you could even modify the dog clutch splines with a jewler’s file (I dunno, maybe you guys have already thought of that and it’s impossible…)
Just a thought.
Here’s the question that I’m not quite sure of, since I don’t have one of these cases to look at and haven’t built one like you all have. You reuse the original shift collar, correct? For those of you like peesalot that are talking about the gears “wearing in”, what is it that you propose wears into what? You get new gears, so you are saying that the splines on the old shift collar (which are at a factory 2 deg taper) wear a negative angle into the straight cut splines of the new gears? Is that the idea?
Not having the parts on hand, I can’t really get a good idea… but what do the internal splines on the gears look like? How are they cut? Is the bearing ID of the gear in relation to the splines big enough that you could set up some sort of 2 degree jig and give each spline a few strokes of a jewlers file in order to start setting the proper taper? If it could be done, what would you be talking, 50 teeth or something? Nothing that a few hours and some beers couldn’t handle. ASSUMING that the gear was designed such that you could even modify the dog clutch splines with a jewler’s file (I dunno, maybe you guys have already thought of that and it’s impossible…)
Just a thought.
Are the problems people have mainly with high-power (V8's)? Or is it more of an engine braking problem (descending hills)?
I also really, really, really want one but am nervous about the popping out.
I'd be more concerned about it popping out descending a hill than applying power. I'm going to use a basically stock 2F motor in my FJ-40......
I also really, really, really want one but am nervous about the popping out.
I'd be more concerned about it popping out descending a hill than applying power. I'm going to use a basically stock 2F motor in my FJ-40......
