Rear diff just let go

[David Harris]

Perhaps we could make this already good thread into a great thread by putting out a definition of what "full float" means, and also delving a little deeper into the D2 axle?

Full-float means that the full weight of the vehicle is supported by the wheel bearings in the hub alone, which in turn is supported by the axle housing. The axle shafts run independently and only have to turn the wheels, not support the weight of the vehicle as well. On semi-float axles, the bearings are pressed directly on to the axle shafts, which therefore have to both support the vehicle weight and turn the wheels, thus making a weaker unit. As Teriann said, the full float design also allows one to completely remove the axle shafts and drive shaft, and continue to run the vehicle on the other axle in two wheel drive. In a semi-floating design, the hub/wheel will separate from the vehicle when the axle shaft breaks, since they are an integral unit, and you are going nowhere without a repair on the spot, or trailer.

 

[mongosd2]

Perhaps we could make this already good thread into a great thread by putting out a definition of what "full float" means, and also delving a little deeper into the D2 axle?





I know nothing about this subject. But I've heard the debate, and it has never included any detailed info one way or the other. I'd love to hear it. So far, this just sounds like opinion.

If you really want an the info, go search DWEB and Pirate on the subject, it has been beat to death and the info is there, along with the debate on everything from gear strength to axle breaking numbers.

but to answer your 1st question (stolen from a 4x4 mag)
A semi-floating axle is very common on the rear of most 4x4s. It consists of an axleshaft on each side that is splined on the inner end where it mates to the differential and has a wheel flange where the wheel studs mount at the other end. This assembly typically mates to the end of the axlehousing using some type of flange arrangement. The axleshaft also rides on a large roller or ball bearing out at the end of the axlehousing.

The axleshaft in a semi-floating assembly serves two purposes. First, it attaches to the wheel and is used to support the weight of the vehicle and its cargo. Second, the axleshaft must transmit the rotational torque from the differential out to the wheel.

A full-floating axle can be found on the rear of some 4x4s, but it is generally reserved for vehicles that are designed for severe duty, or are intended to carry heavy loads. This type of axle uses an axleshaft on each side that is simply splined at both ends or splined on the inner end and has a drive flange on the outer end. The shaft mates to the differential in the same way as a semi-floater. However, the outer end of the shaft differs. Here, the splined end of the shaft slides into a locking hub or an internal splined steel drive plate that bolts to a hub cap, similar to what is found on a front axle. In some cases, the drive flange may be part of the shaft itself. In either case, the axleshaft is allowed to float in the system.





I'll post up the differences between a D1/D90 axle and a D2 when I get more time...

 

[Viggen]

I went with the Ashcroft axles. Was going to go with Rover Tracks stuff but Justin didnt have any but did have the Ashcrofts stuff so I went with that kit of rear shafts and HD flanges. Ill throw in new Ford Ranger bearings (which apparently fit) and be good. Ill have shafts with a guarantee not to break and a Detroit so if I manage to break something, Im either doing something very wrong or Im doing something very right. I guess it depends on your viewpoint. A 3.9, auto trans and 255/ 85s shouldnt be enough in regular wheeling duty (trails with mud and decent rocks in between clearings for good tent pitching).

When the front goes, or I have the extra dough in a couple of months, Ill upgrade the front with a TT (or ARB) and a Rover Tracks Long Tracks kit and be done with it.

Anyone that calls a Dana 60 weak makes me laugh. You are going HARD if a D60 is too little for you. Anyone on this board, including myself, would think a D60 is THE setup. Hell, the axle Ill have done next weekend will fit my purposes perfectly. 14 bolts are crazy overkill and have a HUGE drawback, namely the HUGE center section. Youre gaining strength but losing clearance due to the size of the center section. In high school when my buddies and I spent our time leafing through the pages of 4Wheeler, we always spec'd our dream builds with 14 bolts or higher. Now that Im actually building and not just dreaming, reality has set in. A Rover FF rear with better carrier and HD shafts is more than enough for me. Maybe pegging the gearset would clinch it. Jeep guys go with insane axles for no real reason other than pissing contests if you ask me. No small block powered Jeep that does regular wheeling needs a 14 bolt or stronger. No one. Im waiting for the day when people start saying that Rockwells out of deuce and a halves are too weak for their short wheel base Jeep.

The Series III 109 I will buy will have a Salisbury rear and I will call it a day. Itll be more than enough for my gear, travels and I.

 

[David Harris]

Anyone that calls a Dana 60 weak makes me laugh. You are going HARD if a D60 is too little for you. Anyone on this board, including myself, would think a D60 is THE setup. Hell, the axle Ill have done next weekend will fit my purposes perfectly. 14 bolts are crazy overkill and have a HUGE drawback, namely the HUGE center section. Youre gaining strength but losing clearance due to the size of the center section. In high school when my buddies and I spent our time leafing through the pages of 4Wheeler, we always spec'd our dream builds with 14 bolts or higher.

Trust me. Just about anything can be weak depending on what your asking it to do. The reason why hard core rock crawlers have to mod even D60's to make them last is the huge tires (42"+) and super low axle twisting gearing (100:1+) they are running. Put those tires and gearing on an unforgiving top difficulty level trail in Moab or elsewhere and stock D60's can break easily. The 14 bolts are a reaction to the broken D60's. They get by the huge center section of the 14 bolt by shaving the bottom off. The housing is so strong, that it can take being cut-down. Anyway, this is pretty much completely off-topic where most Rovers are concerned.

 

[R_Lefebvre]

Full-float means that the full weight of the vehicle is supported by the wheel bearings in the hub alone, which in turn is supported by the axle housing. The axle shafts run independently and only have to turn the wheels, not support the weight of the vehicle as well. On semi-float axles, the bearings are pressed directly on to the axle shafts, which therefore have to both support the vehicle weight and turn the wheels, thus making a weaker unit. As Teriann said, the full float design also allows one to completely remove the axle shafts and drive shaft, and continue to run the vehicle on the other axle in two wheel drive. In a semi-floating design, the hub/wheel will separate from the vehicle when the axle shaft breaks, since they are an integral unit, and you are going nowhere without a repair on the spot, or trailer.

I pretty much had deduced that already, it's more for the benefit of others.

I would propose that the D2 axle is not infact a semi-floating axle. It's... somewhere between the two. The outer hub is pressed into the bearing, and supports 100% of the load. However, you cannot run with the shaft removed, because the shaft retains the hub in the bearing.

One could however, cut off the axle shaft, and use the left over stub to retain the outer hub in the bearing.

None of the vertical load is supported by the shaft at all. In fact, the hub retention duties could be replaced by a large bolt.

 

[muskyman]

The DII is a unit bearing design.

It is neither a semi floater or a full floater.

 

[Chazz Layne]

One could however, cut off the axle shaft, and use the left over stub to retain the outer hub in the bearing.

None of the vertical load is supported by the shaft at all. In fact, the hub retention duties could be replaced by a large bolt.

I opened this thread because I have a bad feeling my axle is about to die too (3 oil flushes in the last 3k miles have been sparkly black ), but now I can't help but wonder: could this be a route to making a new axle for my new-to-me trailer so I can run the same wheels/tires on it as I do on the D2?


Sorry for the thread hijack...

 

[Rovertrader]

I would recommend a trailer axle with the D2 hub affixed yielding the same end result albeit lighter and no diff hanging down.

 

[R_Lefebvre]

I opened this thread because I have a bad feeling my axle is about to die too (3 oil flushes in the last 3k miles have been sparkly black ), but now I can't help but wonder: could this be a route to making a new axle for my new-to-me trailer so I can run the same wheels/tires on it as I do on the D2?


Sorry for the thread hijack...

I don't see why not. Other than the fact they are unservicable, and will give you the same problems as they do in the D2. $500 wheel bearings on a trailer?

I'm facing this right now with my D2, as I need a new front hub.

What might be involved in swapping down to a D1 axle and just get rid of the ABS and all the 3 amigos problems?

 

[David Harris]

What might be involved in swapping down to a D1 axle and just get rid of the ABS and all the 3 amigos problems?

Well, you'd definitely end up with a better axle. Computer issues might cause some problems on a D2?

 

[Root Moose]

What might be involved in swapping down to a D1 axle and just get rid of the ABS and all the 3 amigos problems?

If you are going to take it that far you might want to consider other axles besides the LR stuff. I'm not a big fan of Dana stuff from a engineering/design point of view (****** were they thinking?) but cheap and easy is hard to resist some times. I like the Aisin stuff better (TLC) but it's typically not as cheap and easy as the Dana stuff.

I'd expect a high pinion Dana 44 with aftermarket carrier and maybe axles would be all a D2 needs for your usage. Something blingy like a custom 609 type axle (60 outers, 9" diff) would be cool. There's lots of other issues to going these routes of course (fitment, axle geometry, bolt pattern, etc.).

If you eliminate all the electronics don't you get rid of the hill descent control and such? Sure you want to do that? Just fix what's broke and move on?

 

[Toy-Roverlander]

LC80 axles and be done with it, wouldn't you agree mr Mongosd2:ylsmoke:

 

[mongosd2]

If I were to do it again, I'd dump the D2, buy a D1, do a toy conversion with arb's and 4.11's, run 285's or 305's and be done with it...

 

[Chazz Layne]

The extra length of a D2 lets me use it as a "tent" though.

The only thing I think I'd miss dropping to D1 axles is the traction control. Even at the point I have lockers, I could still picture myself appreciating the T/C on ice/snow with the lockers unlocked.

I only occasionally use HDC, and then only when I want to scare the wife. It works, but not any better than low-1st (or low-2nd in some cases).

 

[R_Lefebvre]

Well, you'd definitely end up with a better axle. Computer issues might cause some problems on a D2?

You forget, I'm the guy that just put an R380 in a D2.

But now that I'm thinking about it... I'd lose the speedometer. That would mildly suck.

If you are going to take it that far you might want to consider other axles besides the LR stuff. I'm not a big fan of Dana stuff from a engineering/design point of view (****** were they thinking?) but cheap and easy is hard to resist some times. I like the Aisin stuff better (TLC) but it's typically not as cheap and easy as the Dana stuff.

I'd expect a high pinion Dana 44 with aftermarket carrier and maybe axles would be all a D2 needs for your usage. Something blingy like a custom 609 type axle (60 outers, 9" diff) would be cool. There's lots of other issues to going these routes of course (fitment, axle geometry, bolt pattern, etc.).

If you eliminate all the electronics don't you get rid of the hill descent control and such? Sure you want to do that? Just fix what's broke and move on?

All good points.

Yes, HDC would be gone, but I don't care with the manual transmission. I don't see why I'd ever use it now. Traction control and ABS would be gone. I don't care about the traction control so much once I have lockers. The ABS I do somewhat care about... Though I could live with it. I don't have ABS on my trackday car and it doesn't bother me. But it stops just a little better than my truck so...

Yeah, there's lots of issues to solve. But it also solves lots of issues. So let's say I'm sitting here, wanting a locker, and wanting to regear, and wanting stronger axles, and wanting steel wheels which is hampered by the odd bolt pattern. And maybe even wanting to upgrade to 4 piston opposed calipers... Wouldn't changing to a more common axle make all these problems easier and cheaper? Couldn't it actually pay for itself, in fact? I wonder.

To just fix what's broke means spending $500 on a wheel bearing. Then $1000 on each locker, $500 on each gear? $1000 on axles? And then $1500 on the other 3 wheel bearings, and then maybe $1500 for the SLABS actuator some day....

The extra length of a D2 lets me use it as a "tent" though.

Exactly. I like the D2 for it's extra cargo capacity, comfort, sound deadening, etc. etc. etc. I'd just like to simplify a few things that they took too far.