Thread: Stuck in the mud

Hi all,

Sorry to semi-hijack this thread, but being a new RRC owner I've found it an interesting discussion. I've got one of the first 3.9 RRC's (Nov '89?) which I bought solely for towing my very heavy boat and some bush bashing. I've been away for work for most of the time since I bought it in July so haven't had much time to play with it. I have a lot of questions which I'll leave for another thread, but for now I'd like to know about the Hi/Lo/Diff lock features if someone is willing to shed some light on my car. I understand the difference between Hi and Lo and sort of understand about a Diff locker. Am I right in assuming my '89 RRC doesn't have the Diff locker feature, since the knob only has L/N/H?

I'm away (again) for work at the moment so can't read through the car's owners manual, etc. I also assume my Hi/Lo knob is skewiff and should be fwd/aft, not L/R?

Sorry fonfe if I've hijacked your thread. Just saw it as a learning opportunity for myself and hopefully a few other newbies.

-Scott

Assuming that is the correct knob, and that it can only move between 3 positions fore/aft, and NOT a sideways to the left....then you've got the Borg Warner transfer case.

This means you have no control over the 'automatic' locking of the centre diff, its done for you by a gizmo called a Viscous Coupling, or VC.

Your centre diff splits the drive between Front and Rear axles, and in normal on-road life this, "diffing" is what you want.

But like all differentials, if one side is free, then ALL the drive goes there, and the other wheel stops. In an AWD (All wheel drive) this is doubly tragic because it means if ONE wheel loses traction, then ALL the drive goes there and THREE wheels stop. - You go nowhere... You need to lock the centre diff so that equal amounts go the front and rear axles, which means if one wheel spins, the other side of that axle stops but the other axle keeps going to get you out of the mess.

Rather than have a lever or driver-operated device to lock the front/rear drives together, the VC senses when the centre diff is doing a LOT of 'diffing... and locks the front/rear together thus giving you a solid 4WD.

In short, the VC automatically engages (Locked) 4WD almost as soon as it's needed. Then reverts back to alowing a small amount of 'diffing'....

From reading here, it seems the VC setup suits sand and beach work, but is less favoured for 'dry' work such as rocky or very rugged country.

When a VC fails, it usually locks up solid. This is Very Bad and Expensive, as it chews out your tyres, puts huge loads on your transmission and front CV joints. - The tyres chirp on cornering and the turning circle is bigger. Especially in the wet... You know Something is Not Right...

Sometimes they fail 'permantly open' in which case no damage done except to pride when you get immobilised on the beach. Otherwise you'd never suspect anything is wrong.

Its pretty simple.......

A viscous coupling never actually locks (when healthy), instead it just limits the difference in shaft speed. Like traction control it requires one end to be slipping to transfer more torque to the other end.

To be truely locked, it needs to be a mechanical diff-lock like the LT230 or in axles an ARB.
The main question is, do you require a full lock for your sort of driving? For most the answer is no. Viscous or traction control effects are enough.

So if its a vicious coupling does it act like an LSD on normal 2wd car? If that's the case I get how it works now

Will get a new knob for mine but until then I have a reminding post it note!

Freudian slip there Fonfe... 'viscious coupling'.... (spelling) - They are very 'Viscious' to your wallet when they die.

Dougal has it right, they are'nt supposed to lock solid in operation as the Magic Fluid inside them relies upon the shearing effect to trigger the partial locking.

The care and feeding of a BW transfer case centres around keeping both axles at the same speed. - So always replace all 4 tyres at the same time... NEVER just one axle...

Will you be over Bendigo way through your Christmas holidays at all? We'd love to go to Mt Speculation then but have a bub due any day now - so that won't be happening; but a 4wding day around Benders would be great!

I'm not sure how much you know about 4wding, however if you do a recovery use rated gear, and never attatch anything to a tow ball - the towpack is fine though.

Lots of interesting discussions mate. Low range would help but possibly not from that bog hole you got into. Rubber? AT tires would have spun in low range but it would be unlikely to remove you from that one. Mud Terain and low range and you might have. Your orgional thought on a winch followed mine after getting stuck (with Low range and tractions controls in several mud pits or steep muddy tracks - yep a Disco 3 person)

Mates are helpfull but only if they or you have snatch straps and recovery points.

Lots of posts on cheap and not so cheap winches which I would not leave home with out over winter in mexico
I have one of the cheaper ones. Had one of the cheapest for years untill "I" broke it. Second hand might work if your good at repairs and maintainace. My 6month old Tigerz has not been used in anger mostly due to M.T. tires I run in the bush now. Have fun getting dirty.

I wonder if his BW rear output shaft is stripped and just spun under the pressure of mud then jammed again in normal driving, or the chain jumped sprockets

Possible but maybe improbable but could explain no wheels turning as this is impossible unless the TC is in neutral otherwise.

Regards Philip A