Wrecked my TTB

[grumpin]

Bob - Thanks for the detailed explanation.

Yes, thanks! I like your one tire jacked test.

[Rusty_S85]

Yep, I have always wondered why they even offer lockers for 4wd applications. I can see a posi but not a out right locker. But the TTB unit I was looking at they dont offer a truetrack gear posi like I will be running in my 9", only a stock open type differential or a locker type.

Because that's where the biggest market is? The vast majority of people who would buy a locker already bought a 4WD. And while the front axle is usually considerably weaker than the rear, most people seem to agree that a locker in the front is more helpful than a locker in the rear in most situations.

And the Eaton TrueTrac is made for the Dana 44 TTB. I would assume the Eaton posi is as well, but the posi is a clutch-type limited slip, not the gear type like the TrueTrac.

And having had lockers in three different rear axles and two fronts and a TrueTrac in one rear axle, I'll say that a TrueTrac doesn't come CLOSE to the performance of a locker. Sometimes that's good because it doesn't have the bad manners of a locker. But if you have one tire getting no traction (common in rock crawling or when ice is a factor) a TrueTrac does very little. The TrueTrac works best when both tires get at least semi-decent traction.

I dont do rock crawling. mine is a daily driver and there may be ice but the whole design of the truetrac in every document from Eaton themselves state that it transfer power to the wheel with better traction just like a clutch style posi, but if both wheels have the same amount of traction then there will be no transfering of power. So if I was going down the road and hit a patch of ice both tires will have the same amount of traction and wouldnt have a shift in power. But if I move off the road slightly and my right tire hits the dirt on the side of the highway that less traction there will force a shift to the left tire on the pavement.

As far as ice itself goes, with AT tires just about all name brand ones ive seen stated they provide traction on ice/snow/mud so like my KO2`s even hitting a patch of ice there should still be some kind of traction on both wheels even if there is one wheel slipping more than the other.

[Gary Lewis]

Yep, I have always wondered why they even offer lockers for 4wd applications. I can see a posi but not a out right locker. But the TTB unit I was looking at they dont offer a truetrack gear posi like I will be running in my 9", only a stock open type differential or a locker type.

Because that's where the biggest market is? The vast majority of people who would buy a locker already bought a 4WD. And while the front axle is usually considerably weaker than the rear, most people seem to agree that a locker in the front is more helpful than a locker in the rear in most situations.

And the Eaton TrueTrac is made for the Dana 44 TTB. I would assume the Eaton posi is as well, but the posi is a clutch-type limited slip, not the gear type like the TrueTrac.

And having had lockers in three different rear axles and two fronts and a TrueTrac in one rear axle, I'll say that a TrueTrac doesn't come CLOSE to the performance of a locker. Sometimes that's good because it doesn't have the bad manners of a locker. But if you have one tire getting no traction (common in rock crawling or when ice is a factor) a TrueTrac does very little. The TrueTrac works best when both tires get at least semi-decent traction.

I dont do rock crawling. mine is a daily driver and there may be ice but the whole design of the truetrac in every document from Eaton themselves state that it transfer power to the wheel with better traction just like a clutch style posi, but if both wheels have the same amount of traction then there will be no transfering of power. So if I was going down the road and hit a patch of ice both tires will have the same amount of traction and wouldnt have a shift in power. But if I move off the road slightly and my right tire hits the dirt on the side of the highway that less traction there will force a shift to the left tire on the pavement.

As far as ice itself goes, with AT tires just about all name brand ones ive seen stated they provide traction on ice/snow/mud so like my KO2`s even hitting a patch of ice there should still be some kind of traction on both wheels even if there is one wheel slipping more than the other.

I haven't driven on ice or snow with Big Blue's Truetrac, yet, but I have turned corners on asphalt when it had just started raining. As you know, that brings the oil to the surface and makes things slick. Apparently one of the tires started to spin so the Truetrac sent power to the other tire and both spun and I went sideways. I got off and eased into it again, and now I was going straight, and it came loose again. I tried it several times and before I felt the first tire slip the diff had sent power to the other one and I was walking sideways again.

I'm not at all saying that a Truetrac is bad. I'm just saying that it will transfer power if one wheel slips, and if neither has much traction you'll be spinning.

[Nothing Special]

I dont do rock crawling. mine is a daily driver and there may be ice but the whole design of the truetrac in every document from Eaton themselves state that it transfer power to the wheel with better traction just like a clutch style posi,...

The TrueTrac does transfer torque (which means it also transfers power) to the tire with more traction. Clutch-type limited slips like the Eaton posi also transfer torque/power to the tire with more traction. But the two types do this through very different means.

... but if both wheels have the same amount of traction then there will be no transfering of power. So if I was going down the road and hit a patch of ice both tires will have the same amount of traction and wouldnt have a shift in power. But if I move off the road slightly and my right tire hits the dirt on the side of the highway that less traction there will force a shift to the left tire on the pavement....

I agree with all of that

... As far as ice itself goes, with AT tires just about all name brand ones ive seen stated they provide traction on ice/snow/mud so like my KO2`s even hitting a patch of ice there should still be some kind of traction on both wheels even if there is one wheel slipping more than the other.

I had BFG A/Ts on my truck for the first few winter that I've had the TrueTrac. Late this summer I put on a new set of Michelin M&S rated tires, so I have personal experience with both of those setups. Yes, they get some traction on ice, not exactly the same as having one tire in the air. But at the top of the slight hill 3 blocks from my house, where every morning in the winter I have to stop at the stop sign with my right tires on ice that's been polished by everyone trying to start there, I can spin the right tire as much as I want as the truck s-l-o-w-l-y pulls ahead with the left tire on bare pavement.

I used to have an F-150 with a Detroit locker. That truck would accelerate at that stop sign as hard as I ever chose to accelerate without any noticeable wheel spin. But on the other end of the spectrum, the trucks I've had with open diffs, or the worn out clutch-type limited slip that used to be in my current truck would accelerate even slower than the TrueTrac, and sometimes I'd need to back up and move over to the middle of the road to get off the ice.

So yes, a decent tire will get some traction on ice. But it's often not enough to make a TrueTrac work anywhere close to as good as a locker. It's better than an open diff. A LOT better in some situations. But it's not much better than an open diff at the top of that hill 3 blocks from my house.

After living with both a TrueTrac and a few different automatic lockers I'm not sure which I prefer in my daily driver truck. The TrueTrac definitely has better road manners, but a locker definitely works better in my real-world usage. Generally I'm willing to put up with the worse manners, so generally I'd say I'd rather have an automatic locker in my daily driver than a TrueTrac.

But there are two things that tip me toward a TrueTrac. One is that I feel better about loaning my truck out with a TrueTrac than I do with an automatic locker. Others (including my kids and wife) aren't used to an automatic locker, and it can bite you a lot more easily than a TrueTrac if you don't know what to expect. Also an automatic locker isn't so great for towing, and I want this truck to be able to tow heavy trailers.

(There's also third reason, I already have the TrueTrac and I don't want to pay to change it out)

And none of this is to say that you shouldn't get a TrueTrac for your truck. A lot of people use them and love them. My first post was to say that if the original poster wants the performance of a locker in snow, he likely will be disappointed with the performance of a TrueTrac. On the other hand, if someone doesn't want the bad manners of a locker, and wants to reduce the risk of grenading an axle, a TrueTrac is definitely a great option.

 

[Nothing Special]

I haven't driven on ice or snow with Big Blue's Truetrac, yet, but I have turned corners on asphalt when it had just started raining. As you know, that brings the oil to the surface and makes things slick. Apparently one of the tires started to spin so the Truetrac sent power to the other tire and both spun and I went sideways. I got off and eased into it again, and now I was going straight, and it came loose again. I tried it several times and before I felt the first tire slip the diff had sent power to the other one and I was walking sideways again.

I'm not at all saying that a Truetrac is bad. I'm just saying that it will transfer power if one wheel slips, and if neither has much traction you'll be spinning.

An open diff always sends the same amount of torque to both sides. So it almost always will only spin one tire because almost always one tire will spin with less torque than it takes to spin the other one. A rolling tire doesn't like to slide sideways. A spinning tire is already sliding, so it doesn't care which way it slides. So an open diff is definitely best for stability.

The good thing about any traction aiding diff is that it will send more torque to the tire with more traction. That lets you put more power to the ground, but it also means that it's likely that you will be able to spin both tires. And if the road is pretty slippery it will be likely that you WILL spin both tires. So not traction-aiding dioff will ever be as stable as an open diff (except a selectable locker that IS an open diff when not engaged).

[Gary Lewis]

I haven't driven on ice or snow with Big Blue's Truetrac, yet, but I have turned corners on asphalt when it had just started raining. As you know, that brings the oil to the surface and makes things slick. Apparently one of the tires started to spin so the Truetrac sent power to the other tire and both spun and I went sideways. I got off and eased into it again, and now I was going straight, and it came loose again. I tried it several times and before I felt the first tire slip the diff had sent power to the other one and I was walking sideways again.

I'm not at all saying that a Truetrac is bad. I'm just saying that it will transfer power if one wheel slips, and if neither has much traction you'll be spinning.

An open diff always sends the same amount of torque to both sides. So it almost always will only spin one tire because almost always one tire will spin with less torque than it takes to spin the other one. A rolling tire doesn't like to slide sideways. A spinning tire is already sliding, so it doesn't care which way it slides. So an open diff is definitely best for stability.

The good thing about any traction aiding diff is that it will send more torque to the tire with more traction. That lets you put more power to the ground, but it also means that it's likely that you will be able to spin both tires. And if the road is pretty slippery it will be likely that you WILL spin both tires. So not traction-aiding dioff will ever be as stable as an open diff (except a selectable locker that IS an open diff when not engaged).

Yep. I think the ideal diff is a selectable locker. As you know, I have one on the front of Big Blue, but you may have forgotten/not known that I have one on the back of Blue. Just pull the 4wd switch out and it locks the rear up to something like 10 MPH, at which point it turns off. Would be ideal for the top of your hill.

[Rusty_S85]

I dont do rock crawling. mine is a daily driver and there may be ice but the whole design of the truetrac in every document from Eaton themselves state that it transfer power to the wheel with better traction just like a clutch style posi,...

The TrueTrac does transfer torque (which means it also transfers power) to the tire with more traction. Clutch-type limited slips like the Eaton posi also transfer torque/power to the tire with more traction. But the two types do this through very different means.

... but if both wheels have the same amount of traction then there will be no transfering of power. So if I was going down the road and hit a patch of ice both tires will have the same amount of traction and wouldnt have a shift in power. But if I move off the road slightly and my right tire hits the dirt on the side of the highway that less traction there will force a shift to the left tire on the pavement....

I agree with all of that

... As far as ice itself goes, with AT tires just about all name brand ones ive seen stated they provide traction on ice/snow/mud so like my KO2`s even hitting a patch of ice there should still be some kind of traction on both wheels even if there is one wheel slipping more than the other.

I had BFG A/Ts on my truck for the first few winter that I've had the TrueTrac. Late this summer I put on a new set of Michelin M&S rated tires, so I have personal experience with both of those setups. Yes, they get some traction on ice, not exactly the same as having one tire in the air. But at the top of the slight hill 3 blocks from my house, where every morning in the winter I have to stop at the stop sign with my right tires on ice that's been polished by everyone trying to start there, I can spin the right tire as much as I want as the truck s-l-o-w-l-y pulls ahead with the left tire on bare pavement.

I used to have an F-150 with a Detroit locker. That truck would accelerate at that stop sign as hard as I ever chose to accelerate without any noticeable wheel spin. But on the other end of the spectrum, the trucks I've had with open diffs, or the worn out clutch-type limited slip that used to be in my current truck would accelerate even slower than the TrueTrac, and sometimes I'd need to back up and move over to the middle of the road to get off the ice.

So yes, a decent tire will get some traction on ice. But it's often not enough to make a TrueTrac work anywhere close to as good as a locker. It's better than an open diff. A LOT better in some situations. But it's not much better than an open diff at the top of that hill 3 blocks from my house.

After living with both a TrueTrac and a few different automatic lockers I'm not sure which I prefer in my daily driver truck. The TrueTrac definitely has better road manners, but a locker definitely works better in my real-world usage. Generally I'm willing to put up with the worse manners, so generally I'd say I'd rather have an automatic locker in my daily driver than a TrueTrac.

But there are two things that tip me toward a TrueTrac. One is that I feel better about loaning my truck out with a TrueTrac than I do with an automatic locker. Others (including my kids and wife) aren't used to an automatic locker, and it can bite you a lot more easily than a TrueTrac if you don't know what to expect. Also an automatic locker isn't so great for towing, and I want this truck to be able to tow heavy trailers.

(There's also third reason, I already have the TrueTrac and I don't want to pay to change it out)

And none of this is to say that you shouldn't get a TrueTrac for your truck. A lot of people use them and love them. My first post was to say that if the original poster wants the performance of a locker in snow, he likely will be disappointed with the performance of a TrueTrac. On the other hand, if someone doesn't want the bad manners of a locker, and wants to reduce the risk of grenading an axle, a TrueTrac is definitely a great option.

Of course for me I am going the TrueTrac cause I want a posi in my truck for improved traction. Not looking for a locker, my choices was to go with a traditional locker and run the posi additive or go with a gear locker and just run the same old gear oil as in an open. I like that idea better plus I have seen some posi`s at work that were quite tight on the clutches and trying to make a turn results in a ratcheting effect as the tire hops as its not wanting to slip. I didnt want that either on a daily driver especially with 31x10.50-15 tires.

Currently I have the open so I can get a currie third member with a traditional posi or a truetrac and swap it in with the gears I am looking at. So I can go either way if need be still.

[Nothing Special]

.... You are always going to have problems with a true locker if you have traction.

Any time you are turning, each front wheel is traveling a different arc, with much different distances.

This is why we have differentials to begin with!

So, you found the weak link in your setup.

Probably a lot better than splitting your carrier.

What part do you want to fail?

Because geometry and physics say you can't have both axles turning together.

I was thinking more about this thread and realized that I hadn't commented on this. Stevenscoffee didn't say what type of locker he has. But if it's an automatic locker it will not cause binding. In fact, an automatic locker in a front axle will actually reduce the amount of binding you have when turning in 4WD.

Most differentials are really misnamed. "Limited slip" differentials offer a limited amount of grip, while doing nothing to limit slip once the slip starts. And "automatic locking" differentials actually are better considered "automatic unlocking" differentials.

Automatic (un)lockers will always freely allow one tire to go faster than the ring gear. So when you are going around a corner it will automatically unlock and let the axles turn separately. And this will happen freely whether you are coasting or accelerating. The only way you can keep it from disengaging is to spin the inside tire. Then the ring gear catches up to the outside tire. With the outside tire not going faster it won't unlock. But it's not like people often say who think you need to get off the power to allow an automatic locker to unlock. It knows nothing about power, all it knows is relative speed. So any time one tire wants to go faster than the ring gear it can. Period.

When you go around a curve the front tires track wider than the rear, so the front tires need to turn faster than the rear. But when yo are in 4WD the transfer case (that has no differential) won't allow that so you get some bind. But an open front diff will allow the inside tire to slow down a little while the outside tire goes a little faster. An automatic locker on the other hand won't let the inside tire slow down, although it will allow the outside tire to speed up. So the average speed of the front tires is faster in a curve with an automatic locker. That's why you'll actually get less bind turning with an automatic locker in the front than with an open diff.

That said, open diffs protect axles because they will only send as much torque through either axle as the tire with the least traction will support. That can be considerably less torque than the tire with the most traction can support, and a locker will send that higher amount to that tire. That's why it's a lot easier to break axles with a locker.

And I've been talking here like I'm a big fan of automatic lockers in a front axle. I'm not, at least in all situations. I think an automatic locker in the front could well be the most effective choice for most serious fourwheeling (better than other types of diffs in the front and better than any type of diff in the rear). But the road manners are a lot worse than with an automatic locker in the rear. At low speeds it's just very significant torque steer as the diff makes the tires try pretty hard to straighten themselves out when you are turning or will make it pull toward the tire with the least traction if there's a significant traction difference. But at higher speeds that torque steer can be deadly. The first time I changed lanes on a snowy freeway in 4WD with an automatic locker in the front, when the left front tire hit the snow between the lanes the truck pulled so abruptly to the left that it had moved 10 feet before I was able to catch and correct it. Fortunately I was trying to change into that lane and knew it was empty. The second (and last) time I changed lanes with the front locker I thought I was ready. I back off the gas quite a bit (just enough to keep speed, not accelerating at all) and the truck only jumped over about 5 feet. I shifted into 2WD at that point.

 

[Nothing Special]

Of course for me I am going the TrueTrac cause I want a posi in my truck for improved traction. Not looking for a locker, my choices was to go with a traditional locker and run the posi additive or go with a gear locker and just run the same old gear oil as in an open. I like that idea better plus I have seen some posi`s at work that were quite tight on the clutches and trying to make a turn results in a ratcheting effect as the tire hops as its not wanting to slip. I didnt want that either on a daily driver especially with 31x10.50-15 tires.

Currently I have the open so I can get a currie third member with a traditional posi or a truetrac and swap it in with the gears I am looking at. So I can go either way if need be still.

Sounds like the TrueTrac will be a good choice for you.

 

[Rusty_S85]

Of course for me I am going the TrueTrac cause I want a posi in my truck for improved traction. Not looking for a locker, my choices was to go with a traditional locker and run the posi additive or go with a gear locker and just run the same old gear oil as in an open. I like that idea better plus I have seen some posi`s at work that were quite tight on the clutches and trying to make a turn results in a ratcheting effect as the tire hops as its not wanting to slip. I didnt want that either on a daily driver especially with 31x10.50-15 tires.

Currently I have the open so I can get a currie third member with a traditional posi or a truetrac and swap it in with the gears I am looking at. So I can go either way if need be still.

Sounds like the TrueTrac will be a good choice for you.

Thats what I figured, my truck is more of a pavement truck only time my truck goes off road is when I go out of town and I drive out onto the ground we have or I take a back dirt road. I did hear the TrueTrac is better in a mud/dirt/sand situation than a straight open diff though.