Did OBX mess up my LSD?? (long post)

[chipdogg]

But I respectfully disagree with the statement that under no circumstances will both gears move in or out simultaneously. When you launch hard (which I would make a guess is when ANY differential sees the most stress on all of its internals, regardless of its design), those sun gears are absolutely moving opposite of each other.

Yeah I thought about it during the day and agree with you on this. When the helicals are transfering torque to the side gears, they'll move inwards together.

[chipdogg]

A "cheap" fix to having them on the wrong sides would be to cut down the tall gear to the height of the short gear, and have a spacer machined to match the current height difference, and swap gears, with the spacer going in first. Honestly a pressed-in spacer would be the best. I can stop by my machine shop today to see how much he'd charge for a spacer and cutting the gear down. The difference is ~8mm. OD of the spacer would be ~.003" bigger than the bore, and the ID would just have to be .040" bigger than the axle's OD.

[jonnymopar]

I'll take an old inner CV and fit it together today and take a look. I'm at work right now with nothing in front of me, but if I remember correctly, that setup would result in the same amount of spline engagement, just moved 8mm closer to the end of the axle. It wouldn't work for a Neon with the circlips, but it might work for these older cars.

[chipdogg]

I'll take an old inner CV and fit it together today and take a look. I'm at work right now with nothing in front of me, but if I remember correctly, that setup would result in the same amount of spline engagement, just moved 8mm closer to the end of the axle. It wouldn't work for a Neon with the circlips, but it might work for these older cars.

I think you have it backwards. It'd work with Neon ones too. I'd take material off side of gear by bearing. The gear would remain in the same spot relative to axle clip, helical gears, and that center star thing. I have no idea why on side is wider than the other, they could have bored out the inside of the diff a little less and made them same size, which is what a press in spacer would do. Gear would be turned down from clip end since the splines need to be modified anyways to allow for axle removal, the insertion side is the same. Hell since I have 2 sets of opposite gears, I basically have 2 short ones with opposite splines, which is what I'm trying to create by by cutting down the tall ones.

Pics tonight of what I mean.

[jonnymopar]

I took a look at your idea.

As it is now, passenger-side gear goes in chamfered side down:





so it sits like this:





add an axle:





Looks like you were right on with the 8mm difference:





So with the wider passenger-side gear, the gear splines are fully "choked up" on the axle splines. If you take that 8mm away from the gear and use a spacer underneath it, the gear would sit something like this:




So there's a little bit of the splines not engaged. That's all I was trying to point out in my previous post. I don't have a loose Neon axle to try, but my assumption was that the circlip landed just inside of the splined portion of the wider gear, which means it would be housed in the unsplined portion of the gear. With the spacer, that unsplined portion would now be facing toward the axle instead of facing inward, and the gear splines would sit at a slightly different position on the axle. Again, I don't have a Neon axle to try to confirm.

If worse comes to worse (and OBX doesn't reply to my now 4th detailed email), then I may go the spacer route. There is a nice pocket that would hold it:




I'll have to see what would be a good material to make it with. Gotta be something pretty hard.

[Reaper1]

I think maybe you all are overthinking this...that coming from a guy that overthinks everything to the point I have a hard time getting personal projects done. Anyway, from what I can gather the general thought is that the large gears with the splines in them move. I could be wrong, but I don't think that's the case. Most of us have issues even getting our axles to spline into these units, which are being referred to as the "side gears" in this case if I'm not mistaken.

I understand that the torque being introduced into the diff is a LOT more than what we can induce simply pushing an axle in, but if these gears did move, wouldn't splining them get easier with time as well as show wear on the axle splines? I've had my axles out a few times...I don't remember seeing any indication that this was happening. I had to go back and re-understand how a Torsen type differential works, which these are a derivative of. They use gear bind for than friction of the gear against the housing. From what I can find, the planetary gears are the ones that move on their rotational axis. Once they max out on their small travel, then they bind up. Which way the helix is really has no effect on how the unit works.

Try these:
http://mgaguru.com/mgtech/rearaxle/ra302c.htm
http://www.houseofthud.com/differentials.htm#quattro
https://www.youtube.com/watch?v=lZmsY2YvVsc

This last one is for the Type 1 (aka Type A or Gleason), but the principle is the same:
https://www.youtube.com/watch?v=wiq1Rk5wqds

[chipdogg]

So there's a little bit of the splines not engaged. That's all I was trying to point out in my previous post. I don't have a loose Neon axle to try, but my assumption was that the circlip landed just inside of the splined portion of the wider gear, which means it would be housed in the unsplined portion of the gear. With the spacer, that unsplined portion would now be facing toward the axle instead of facing inward, and the gear splines would sit at a slightly different position on the axle. Again, I don't have a Neon axle to try to confirm.

Take the thinner gear and put it on the same axle, what's it look like? If that's good enough engagement on one axle, why not the other one? It would basically be duplicating what is on the other side. The bore is deeper in one side than the other with the wider gear, and the shallower bore with the narrower gear is what would be basically copied by cutting a gear down and putting an 8mm spacer in.

I talked to Ed Peters about them last week and he said it doesn't matter which way they gears are cut.

[johnl]

I think maybe you all are overthinking this...that coming from a guy that overthinks everything to the point I have a hard time getting personal projects done. Anyway, from what I can gather the general thought is that the large gears with the splines in them move. I could be wrong, but I don't think that's the case. Most of us have issues even getting our axles to spline into these units, which are being referred to as the "side gears" in this case if I'm not mistaken.

I understand that the torque being introduced into the diff is a LOT more than what we can induce simply pushing an axle in, but if these gears did move, wouldn't splining them get easier with time as well as show wear on the axle splines? I've had my axles out a few times...I don't remember seeing any indication that this was happening. I had to go back and re-understand how a Torsen type differential works, which these are a derivative of. They use gear bind for than friction of the gear against the housing. From what I can find, the planetary gears are the ones that move on their rotational axis. Once they max out on their small travel, then they bind up. Which way the helix is really has no effect on how the unit works.

Try these:
http://mgaguru.com/mgtech/rearaxle/ra302c.htm
http://www.houseofthud.com/differentials.htm#quattro
https://www.youtube.com/watch?v=lZmsY2YvVsc

This last one is for the Type 1 (aka Type A or Gleason), but the principle is the same:
https://www.youtube.com/watch?v=wiq1Rk5wqds

Thanks - great links.

[jonnymopar]

Meh, Carlisle is in a month. I'll probably just heave the damned thing back in as-is. If I wanted a Quaife, I should have bought one.

[Reaper1]

Jon, it doesn't matter which way the helix is cut, if that is your concern.

[Ondonti]

And since the axle shears off at the end of the splines I don't think it matters how much engagement you have.

[jonnymopar]

Yeah, I'm pretty far below the axle-breaking power level anyway. Although the weight doesn't help (both the car and me).

Gotta make sure I grab a dial indicator from work so I can shim this thing up and get it installed this weekend.