Thread: Halfshaft clutches - please can someone explain

Originally Posted by isuzurover

It is quite simple to avoid. Only ever engage the rear locker when going downhill...

Reeds90 - can't see how the broken axle had much contrribution to flipping when driving UPhill - but I suppose on slippery mud with too much right foot anything is possible.

I have seen plenty of comp vehicles drive all sorts of terrain with a broken CV - still using the front locker. Unless you are driving down very muddy hills, I can't see this being a big issue.

Another thing to remember is - if you lose traction or start going sideways when driving downhill, ACCELERATE. Most people panic and hit the brakes, when they should be stabbing the accelerator to gain traction and straighten the car up.

mmm more was the fact it was a viscous Auto box that with the combination of the lockers and the broken shaft , caused power to be shifted to the rear wheels causeing this problem . So what happen he was going up a very steep hill . More than 45 degrees and just about at the top when the shaft broke and the auto box sent the power to the back axel and too much power .. It was the 6th time he had gone up the hill . The other 5 times no problem

its not something to worry about...

they screwed the pooch... from right here....

resulted in the decision to go down with both lockers engaged. Frankly we needed maximum engine braking, regardless of the effect this configuration would have on the steering

and then this little pearler

I reached for the grab-handle and offered my navigator's final words of wisdom: "Just keep it straight Patrick"

would be totally contradictory.

hows he ment to steer it if the front wheels are locked together drive wise so cant negotiate a turn?

if hed checked his drive line (easy in a series, drop out the diff lock put it in 2wd and hand turn the front propshaft then try to drive it forwards a little if it wont drive forwards youve done a rear shaft, if you can turn the prop youve done a front) he would have realised what his immediate problem was going to be...

IF he'd used his brain he would have set up differently...

IF you have the front wheels locked to the rear wheels (all 3 difflocks in) as soon as you get any skipping on the rear you're nearly screwed as is with a broken front half shaft if you skip towards the broken shaft youve had it and in most cases your going to be flat bedding the vehicle back and if your lucky you'll be in the ambulance but wont be zipped into one of the body bags they carry.

Heres why.

with all 4 wheels locked together if the rear starts to overtake the front there is nothing you can do to sort it out you cant make an effective turn (untill you lift of spin a front wheel) and you cant just lift off of the brakes as the front axle is only ever going to spin at the same speed as the rear axle.

with the cdl and the rear on the engine will always retard the back wheels equally so if the rear tries to over take the front you just take your foot off of the brakes and the drag of the rear end against the engine or handbrake (LR's and other propshaft braked vehicles only) is more effective against the rears so the vehicle will try to straighten up going down hill, this is even more apparent if you unlock the Center diff as well. Added to this is the fact that with the rear wheels locked together they naturally will add a breaking effort if one wheel needs to turn faster than the other (try pushing a cone shaped basket in a straight line you'll soon work out what I mean)

assuming you know how a bobcat or dozer steers happens when we couple one front wheel to both back wheels. its going to turn and heres where it gets worse... IF your'e trying to engine brake when that happens its also going to yank the steering in that direction. This is going to make the situation worse and its going to kick the tail end of the vehicle out....

and thats all she wrote. From this point on your pretty much just a passenger on a roller coaster ride in a lesson of physics no matter which side of the vehicle your on or what controls are in front of you.

Originally Posted by isuzurover

It is quite simple to avoid. Only ever engage the rear locker when going downhill...

Can you please explain this comment.

Only have a rear ARB locker in the 110 and engage it when think going to have difficulties in going uphill or am likely to get bogged in the mud.

Always looking to understand more.

Regards


Brendan

Originally Posted by leeds

Can you please explain this comment.

Only have a rear ARB locker in the 110 and engage it when think going to have difficulties in going uphill or am likely to get bogged in the mud.

Always looking to understand more.

Regards


Brendan

Just so my comment is clear - if you have F&R lockers fitted, when going downhill it is best to engage the rear only if you are worried about the scenario mentioned above.

If you are driving down a steep, rutted hill (or one with slippery and grippy patches for that matter):
In a vehicle with open diffs at both ends, you will often lurch forward at times when one wheel at each end comes off the ground (or has low enough ground pressure etc to lose traction)
In a vehicle with a rear locker engaged, you descend smoothly, as long as at least one rear has traction at all times. The rear locker engaged also helps keep the car straight.
With F+R lockers engaged, you have some extra control, except you have little or no steering, and it does not assist with keeping the car going in a straight line like the rear does.

I engage my rear locker whenever I am going down a hill that is steep (or rutted/rocky/loose/muddy) enough. It makes a HUGE difference.

Thanks ... that's sooooooooo reassuring ...

Originally Posted by Reads90

This is what happen to my brother when his front half shaft broke with both front and rear locker in and 4.2 V8

YouTube - 90 rolls

Back up a bit Dave (I'm easily confused! )

Originally Posted by Blknight.aus

hows he ment to steer it if the front wheels are locked together drive wise so cant negotiate a turn? What do you mean "can't negotiate a turn?"


IF you have the front wheels locked to the rear wheels (all 3 difflocks in) huh???

with all 4 wheels locked together double "huh"

Screw it ... think I'll go back to knitting!

What do they say, "Ignorance is bliss". I can feel a very blissful moment coming on!

Originally Posted by Panda

Back up a bit Dave (I'm easily confused! )

Never tried to turn a corner with your front locker engaged???

Originally Posted by isuzurover

Never tried to turn a corner with your front locker engaged???

Thats something that a lot of people comment on, but when I do it.... well, the Disco just turns. The turning radius is increased a little, but nothing worth talking much about.