Engaging 4x4 Without locking hubs

[Bruin Beer]

They only sad property about the Patrol 4L is that it does not seem to be useable to reverse a heavy trailer into tight spots.
As soon as 4L is selected and you reverse at the smallest of radiuses the hole drive train winds up and start to bind ( or am I the only guy experiencing it).
Would have liked to have the low range power and control in such situations or is there some trick to be pulled?
Great educational thread going.
Thank you.
Bruin Beer.

[Kagiso II]

- Beer - that is not right in my experiences ?? I will ask Mike Swann to comment
Do you perhaps have a difflock installed [Auto locker I mean? one you don't know about?]

[Stefaansie]

Bruinbeer,

Die slim ouens sal beter kan comment.

As jy AUTO hub locks voor op het sal die drivetrain op wind in 4L op goeie traksie oppervlak en skerp draaie. Sover ek weet het al die Oompie karre manual hub locks op en dan sal hy nie so opwen nie. As hulle nie gesluit is nie natuurlik.

Die voorste diff en side shafts sal draai met 4L, maar nie die wielle(op die hubs) nie. Dus behoort die drivetrain nie op te wen nie.???

[Bruin Beer]

Oom Mac,
Ek het auto lockers voor op en niks in die diff (waarvan ek weet nie).
Dit gebeur in die Auto posisie.
Dit sal nogal 'n lekker verrasing wees.
Bruin Beer

[AndriesS]

Die 4.8 het oorspronklik auto hubs en as die intensy van 4L eintlik is om net stadig te reverse (so eintlik soek jy n 2L) gaan dit nie werk nie omdat die hubs sal lock en op goeie oppervlak sal hy die drivetrain op wind. As jy dit wil doen sal jy i.p.v auto hubs maar manula hubs moet kry . dan kan jy selfs lekker soos PC in die verkeer kruip

[marakasmalan]

Hello Folks,

One very important factor that is not being pointed out: There is a grave danger in using hubs unlocked and swiching to 4L.

The engine produces a maximum amount of torque on the crankshaft and this torque is transfered to the wheels via the drivetrain. The gearbox can increase this amount of torque (on the propshafts and halfshafts, at the crank it will remain independant of gear ratios). Accordingly, the driveshafts/propshafts and halfshafts are designed according to transfer this amount of torque. Engaging 4L will result in the maximum torque possible to be transferred by the drivetrain. If four wheels have traction and 4x4 is engaged with hubs locked, this amount of torque will be split between four halfshafts. If three have traction, the torque will be split between two halfshafts, unless there is a difflock engaged on the axle where one wheel does not have traction, in which case it will be split between 3 halfshafts. Hence, you greatly increase the stress on the rear halfshafts when using 4L without front hubs locked, and it is very likely that all the torque will be transferred via one halfshaft and at the very least by two halfshafts. Hence be carefull, should you decide to do it, at least never do so with the rear diff-lock engaged, as you will rapidly accelerate the wear and tear on your rear drivetrain, most likely reducing the lifespan of your halfshafts.

Analysing the situation, it becomes clear that with 4x4L and diff-lock engaged (assuming only rear diff-lock) it is very likely to encounter scenarios where all the torque is transferred to terra firma by 1 halfshaft only, but highly unlikely that it will be happening for extended periods of time and the probability of it happening is much lower with front hubs locked. Hence certainly less wear and tear.

It is not without reason that 4x4L is intended for 4x4 only.

Breaking halfshafts this way on a Patrol is easier said than done, greater risk is to the tyres if in adverse terrain.

Regards

Marnus

[Bruin Beer]

Marnus,
I fully agree.
As with any thing in live the further you deviate from the norm the more common sense need to be applied to compensate.
You and Andries is 100% correct that the only thing I (and assume many other 4x4 users) need is 2L. This is not intended to see how quick you can get your 2Ton trailer to the top of the Empire State building but to have grater controlled torque when maneuvering the trailer into a tricky spot.
It might be worth to put manual hubs on the wish list.
Thanks guys for all the inputs.
I was just concerned that I might have a "fault" that I did not realize.
Thanks.
Bruin Beer

[Peter Connan]

Hello Folks,

One very important factor that is not being pointed out: There is a grave danger in using hubs unlocked and swiching to 4L.

The engine produces a maximum amount of torque on the crankshaft and this torque is transfered to the wheels via the drivetrain. The gearbox can increase this amount of torque (on the propshafts and halfshafts, at the crank it will remain independant of gear ratios). Accordingly, the driveshafts/propshafts and halfshafts are designed according to transfer this amount of torque. Engaging 4L will result in the maximum torque possible to be transferred by the drivetrain. If four wheels have traction and 4x4 is engaged with hubs locked, this amount of torque will be split between four halfshafts. If three have traction, the torque will be split between two halfshafts, unless there is a difflock engaged on the axle where one wheel does not have traction, in which case it will be split between 3 halfshafts. Hence, you greatly increase the stress on the rear halfshafts when using 4L without front hubs locked, and it is very likely that all the torque will be transferred via one halfshaft and at the very least by two halfshafts. Hence be carefull, should you decide to do it, at least never do so with the rear diff-lock engaged, as you will rapidly accelerate the wear and tear on your rear drivetrain, most likely reducing the lifespan of your halfshafts.

Analysing the situation, it becomes clear that with 4x4L and diff-lock engaged (assuming only rear diff-lock) it is very likely to encounter scenarios where all the torque is transferred to terra firma by 1 halfshaft only, but highly unlikely that it will be happening for extended periods of time and the probability of it happening is much lower with front hubs locked. Hence certainly less wear and tear.

It is not without reason that 4x4L is intended for 4x4 only.

Breaking halfshafts this way on a Patrol is easier said than done, greater risk is to the tyres if in adverse terrain.

Regards

Marnus

Sorry, within the uses invisaged in this post I do not agree. Yes, more torque can be introduced into the half-shafts in 4l than in 2h or 4H. 2.02 times more in fact. But that torque will only be produced if there is sufficient resistance, and in the usages invisaged that will not happen. The torque actually produced will be commensurate with the resistance to motion, which should be relatively low.

Yes, it will be possible to break things if you carry on like a hooligan, but this is not what we are talking about here?

[davidvdm]

Have to agree with Peter here. We are talking about 4L to enable a very slow speed to negotiate something like a trailer with your foot off the clutch instead of speed you would usually have in 2H. The "power" does help, but it is the crawl that is of more use instead of burning the clutch.

I have used mine in 4L many times here in our little town when the "foreigners" from the other side of the Vaal River have ended up in irrigation ditches and need to be towed out. But it is all on tar surface and only once have I needed more traction than two wheel drive could give me and locked the hubs. All four wheels lost traction for a moment or two on the tar, but we were pulling a Pick 'n Pay 18wheeler back onto a flat surface after he lost drive on the two wheels that were in the air (the truck was empty by the way).

Peter, you mention 2.02 times the torque, is that the reduction ratio you get from the low range in the transfer box? What is our actual/standard reduction ratio?

[Peter Connan]

David, that is the reduction ratio in the Patrol's (Y60 and Y61) transfer box. Not sure what yours is, but you should be able to find it either in your manual or on Google.

The actual will however be slightly different as the friction losses will be different.