Perentie drive line 6x6 & 6x4

[Jackofalltrades]

Hi,

been looking at the 6x6, to buy,

but their seems to be constant 6x6 hi/low and the other 6x6 / 4x6 hi/low

is this correct ??

Reading the adds talking to owners, but I can't see mention of this on he web...

if correct which is the more durable / or why the change?

thanks

[123rover50]

Dont quite know what you are getting at.
They are constant drive with the 2 forward axles as in 4x4 with a centre diff lock then selectable drive to the rear or third axle.
On mine the third axle is set up to drive when I lock the centre diff. They are all vacuum operated shifts.

keith

[isuzutoo-eh]

As Keith says. On-road you have the front two axles powered, with an open centre diff to prevent wind up. The rear axle just goes along for the ride when the centre diff is open.
When you lock the centre diff, the rear axle is also engaged.

[Jackofalltrades]

Hi,

Yes understand the centre diff set up with the gear box, constant 4wd 1st 2nd axle,

Question is around rear axle,

the rear axle is driven by the pto, Which needs to be engaged for 6wd ?

so what happens when they have PTO winch?

Or or is the rear axle being driven all the time? which would contradict free wheel hubs on the rear...

[Bearman]

Hi,

Yes understand the centre diff set up with the gear box, constant 4wd 1st 2nd axle,

Question is around rear axle,

the rear axle is driven by the pto, Which needs to be engaged for 6wd ?

so what happens when they have PTO winch?

Or or is the rear axle being driven all the time? which would contradict free wheel hubs on the rear...

The rear axle drive unit gear is driven off the low range gear on the intermediate shaft which is in contact with the centre diff gear. This drive unit is selectable by a vacuum cylinder the same as the centre diff lock and actuated when you lock the centre diff. The rear output unit bolts onto the rear cover plate where a PTO would normally sit. The Perenties have a bottom PTO for the winch that is part of the cover plate that bolts onto the sump of the transfer and is driven by a chain that comes off the transfer input gear on the rear of the gearbox mainshaft. So the rear axle is only DRIVEN when you lock the centre diff but unless you have free wheeling hubs it will still turn or "windmill" all the time regardless of whether the actuator is locked or not. Hope that explains it!! I have free wheeling hubs on the rear axle of mine and changed the vacuum locker lines around a bit and added an extra switch so I can lock the centre diff without locking the rear axle drive unit. Reason I did this is so that I can lock the centre diff on the move and not damage my rear axle drive unit as it will not be turning with the freewheelers disengaged.

[Jackofalltrades]

Thanks Brian,

needed the detail, wasnt aware of the vacuum setup,

is it possible that centre diff can not ingage but the rear axle can?

also should say have not seen one in person, understood how it should work but had contradictory info,

system was the same from start of production to the last of them?

[Jackofalltrades]

I have free wheeling hubs on the rear axle of mine and changed the vacuum locker lines around a bit and added an extra switch so I can lock the centre diff without locking the rear axle drive unit. Reason I did this is so that I can lock the centre diff on the move and not damage my rear axle drive unit as it will not be turning with the freewheelers disengaged.

Did the free wheel hubs make much of a change?

have driven much off road mud or sand, is wheel spin a problem with centre diff locked?

[Bearman]

Thanks Brian,

needed the detail, wasnt aware of the vacuum setup,

is it possible that centre diff can not ingage but the rear axle can?

also should say have not seen one in person, understood how it should work but had contradictory info,

system was the same from start of production to the last of them?

Anything is possible but if everything is operating correctly the centre diff and the rear axle drive should engage together. In normal configuration they are both plumbed into the same vacuum lines so if the vacuum cylinders are good they will both actuate at pretty much the same time. Yes they are the same from start to end of production in this area. The later Bushranger models had some small differences in some areas to earlier production but the 3rd axle drive setup is the same.

[Bearman]

Did the free wheel hubs make much of a change?

have driven much off road mud or sand, is wheel spin a problem with centre diff locked?

I don't know whether the freewheelers have made much difference to fuel consumption but the main reason I wanted them was to stop the rear axle internals and drive shaft from turning when I don't want to use it. Now the rear diff and driveshaft should last virtually forever as I rarely engage it. Haven't done any mud work so far but have done some bush work and sand driving. I have Detroit no-spin lockers in both rear diffs plus a Trutrac in the front so don't get any wheelspin at all.

[101 Ron]

I might add the rear axles drive set up was not designed for the Perentie.
The set up was developed for the Forward control military 101 landrover.
The 101 Landrover was designed from the start for a power driven trailer and why the same transfer case is set up the way it is.
The 101 Landrover has a completely different winch, but the drive for it is taken via gears from the bottom of the transfer case.

[Jackofalltrades]

Anything is possible but if everything is operating correctly the centre diff and the rear axle drive should engage together. In normal configuration they are both plumbed into the same vacuum lines so if the vacuum cylinders are good they will both actuate at pretty much the same time. Yes they are the same from start to end of production in this area. The later Bushranger models had some small differences in some areas to earlier production but the 3rd axle drive setup is the same.

Whats best way to check vacuum cylinders are working properly?

Also thankyou you for answers, no real info on the web or other threads

[Jackofalltrades]

I might add the rear axles drive set up was not designed for the Perentie.
The set up was developed for the Forward control military 101 landrover.
The 101 Landrover was designed from the start for a power driven trailer and why the same transfer case is set up the way it is.
The 101 Landrover has a completely different winch, but the drive for it is taken via gears from the bottom of the transfer case.

Knew the history of where the rear axle drive setup originated, though powered trailers are bit of fun off road.

[Bearman]

Whats best way to check vacuum cylinders are working properly?

Also thankyou you for answers, no real info on the web or other threads

No worries, apart from the dash lights coming on when they lock, the only other way to check is jack up a wheel and see if it is locked or not.

[GMDMD53]

The rear axle drive unit gear is driven off the low range gear on the intermediate shaft which is in contact with the centre diff gear. This drive unit is selectable by a vacuum cylinder the same as the centre diff lock and actuated when you lock the centre diff. The rear output unit bolts onto the rear cover plate where a PTO would normally sit. The Perenties have a bottom PTO for the winch that is part of the cover plate that bolts onto the sump of the transfer and is driven by a chain that comes off the transfer input gear on the rear of the gearbox mainshaft. So the rear axle is only DRIVEN when you lock the centre diff but unless you have free wheeling hubs it will still turn or "windmill" all the time regardless of whether the actuator is locked or not. Hope that explains it!! I have free wheeling hubs on the rear axle of mine and changed the vacuum locker lines around a bit and added an extra switch so I can lock the centre diff without locking the rear axle drive unit. Reason I did this is so that I can lock the centre diff on the move and not damage my rear axle drive unit as it will not be turning with the freewheelers disengaged.

Hello Brian

I read this with interest as I have Free Wheeling Hubs (AVM) also. You say you wanted to be able to engage the Centre Diff without damaging the rear axle drive. I have been engaging and dis-engaging mine (only at low speed). Is this not o.k to do? Also since installing my Free Wheeling Hubs I have wondered if it was o.k. to do the same with the Hubs in 4x2 (dis-engaged)? I did this in Low Range once and the High/Low Selector jumped out several times. I figured maybe no load on the Rear Axle caused this?

On a different note, I have removed my Hubs temporarily as the axles were leaking a lot of oil. I have found replacement inner seals (RTC5992) at LR Spares in the U.K. which are very expensive so I hope they do the job. I have been told, to replace these seals the Diff Crown Wheel etc has to be removed to gain access to the seal. Is this right?

A few people have said that I should be concerned that if the Free Wheeling Hubs allowed the oil to leak that water will get in. Is this a serious problem or just a matter of regular maintenance?

Thanks again for your time.

Regards

Guy

[JDNSW]

If you have the free wheel hubs disengaged, and engage the centre diff lock (and hence the rear - rear axle drive) while moving, the dog in the transfer case is trying to engage a moving part with a stationary part. Depending on the speed you are going, this may result in anything from minor wear and a bit of noise to catastrophic transfer case failure, but is never a good idea.

[Bearman]

Hello Brian

I read this with interest as I have Free Wheeling Hubs (AVM) also. You say you wanted to be able to engage the Centre Diff without damaging the rear axle drive. I have been engaging and dis-engaging mine (only at low speed). Is this not o.k to do? Also since installing my Free Wheeling Hubs I have wondered if it was o.k. to do the same with the Hubs in 4x2 (dis-engaged)? I did this in Low Range once and the High/Low Selector jumped out several times. I figured maybe no load on the Rear Axle caused this?

On a different note, I have removed my Hubs temporarily as the axles were leaking a lot of oil. I have found replacement inner seals (RTC5992) at LR Spares in the U.K. which are very expensive so I hope they do the job. I have been told, to replace these seals the Diff Crown Wheel etc has to be removed to gain access to the seal. Is this right?

A few people have said that I should be concerned that if the Free Wheeling Hubs allowed the oil to leak that water will get in. Is this a serious problem or just a matter of regular maintenance?

Thanks again for your time.

Regards

Guy

G'day Guy, John pretty much explained it. But just to make sure you know what is happening. WITHOUT freewheeling hubs the rear axle driveshaft is turning at the same speed as the other driveshafts as the rear axle wheels are turning the diff which turns the driveshaft so when you engage the centre diff lock the rear axle drive unit vacuum cylinder engages the sliding dog clutch and the transfer case then DRIVES the rear axle instead of it windmilling. WITH freewheeling hubs fitted and in the 4X2 position, the rear driveshaft and diff is stationary. If you engage the centre diff lock while moving the sliding dog clutch will try to engage to a stationary driveshaft while it itself is spinning - you can imagine what damage could result from this. No problem if you stop and then engage it. That is the reason why I added a second vacuum switch. Now I can lock the centre diff on the move without trying to lock the rear axle drive unit. When I have the freewheelers engaged I can have 6X4 or 6X6 by locking/unlocking the second vacuum switch. To replace those seals you are talking about you DO have to remove the diff centre or crownwheel carrier. The reason the rear diff has these seals and not the intermediate shaft is because of the tilt angle of the rear diff - it has to be tilted for the drive shaft to go over the intermediate axle and consequently the oil level has to be higher to ensure an oil supply to the front pinion bearing. Without the seals there would be not enough oil reaching that bearing and it could possibly seize. Last time I had my rear axle engaged I also noticed some oil coming from the breather on the rear diff but after checking it out I have decided that reason this is happening is because the rear diff cover I have fitted (aftermarket HD one) has the breather in a different spot to the original cover and the crownwheel is actually feeding an oil supply straight into the breather when it is turning. Just have to move it a bit to one side and that should fix it. I am also contemplating drilling an extra couple of holes into the axle housings between the diff centre and the hubs and adding an extra couple of breathers there as well as I have found that when I have the hubs engaged my freewheelers leak on the seal where you turn it to engage, presumably from pressure buildup. With regards to the jumping out of gear, it is very unlikely that this is caused by the freewheelere, most likely by wear on the intermediate shaft gear engaging dogs. Hope this helps...........Brian

[GMDMD53]

[QUOTE=Bearman;2728498]G'day Guy, John pretty much explained it....

Thanks again Brian....

I understand your explanation and will certainly avoid engaging 6x6 on the fly with the hubs disengaged.

Regarding The Hi/Low lever jumping out of Low in 6x6 with the Hubs disengaged, it was the first time and so far the only time it has happened. I hope you are wrong about it not being the Hubs being disengaged but suppose only time will tell.