ok a 4 wheel drive question

[extreme-4x4]

so its my understanding the 4wd runs with spring loaded front hubs that are designed to snap when overloaded .... is this right?

so imagine a rocky hill climb and you have to give it some welly to get to the top can the springs snap ?

anyone snapped the springs ?
how hard do you have to push it to snap them ?

id rather know now rather than 3/4 up a hill or stuck in a river trying to climb out

 

[Terranosaurus]

In a word no.

The idea of snap rings comes from people who don't know the difference between break and brake.

The Nissan manual describes them as Brake rings, a poor translation of what should have been clutch rings I suspect.

Contrary to some of the rubbish people say, once locked in they stay locked in, and will not come out until after you disengage 4x4 and then reverse your direction of travell.

The rings do break, when people are clumsy with their use f 4x4. Ie get stuck, stop put into 4x4, then try to set of like a bat out of hell instead of giving the hubs a moment to engage. Once engaged propely you can try as hard as you like but as they engage the Brake rings can get damaged.

 

[jims-terrano]

HB, great description calling them a clutch and more appropriate I guess really.

Lot's of threads regarding Auto Locking Hubs, for some reason my nearside hub seemed to partially engage for no reason, possibly an under lying cause that I never got to the bottom of. I've heard it said that the standard transfer box oil used to thicken slightly at lower temps and cause drag thus kidding the hubs into engaging and replacing with sythetic oil resolved this. It sounds possible but I'm no expert on oils. Anyway I got fed up with replacing my break rings and replaced my auto lockers with manuals. both have pro's and cons but all I can say is I've not had any trouble since changing but neither have I done a great deal of off roading either.

The moral of this is that you should check your 4wd is working correctly if unkown and resolve one way or another. If you only have to replace break rings once it is far cheaper to do so but if it's more than once make your own opinion.

I'm pretty sure that if Auto Lockers are working correctly they are a far better idea than manuals and used correctly shouldn't give much of a problem.

Jim T

 

[Thomas-the-Terrano2]

i'd say you'd only break them if you ran in 4wd on high grip surface ie roads where transmission windup would find a way out thru them.

 

[extreme-4x4]

so if i engage 4x4 carefully prior to getting stuck i should have no problems then ?

although the sticker on my visor says you can select 4wd at any point below 25mph


although i guess 25mph would be quite a shock to the brake /clutch springs

 

[Terranosaurus]

Engaging 4x4 on the move isn't so much of an issue as everything is turning. Its when 4x4 is engaged when stationary then people gun the engine and drop the clutch hard to try and get out that the damage is often done.

Mine were damaged when I bought it, I bought a second hand pair of hubs for £25 and out of the 2 sets made up one good pair of hubs and have had no trouble ever since.

Even driving in 4x4 on hard dry surfaces is unlikely to damage the hubs, the CV joints or half/drive shafts are likely to be the first things to go. Anyone who has had their hubs fully apart will have seen the big gears that lock together to engage the hubs, once locked in the brake rings do no more work until you dissenage, all the power is transmitted through the locked gears.

 

[(RIP) PLANK]

adding to the above, if you look at a Nissan exploded diagram they refer to the sprung circlips as snap rings, I suppose as they snap into place, and the bits that break are brake rings. I think this is where the confusion comes from. I also believe there is no evidence to suggest they are designed to break under excessive stress, i think they just do.

I have messed with a few auto hubs and i think poor lubrication is their worst enemy, I have done this with some success, take the hub off, put a good dollop of engine oil in it (about a good table spoon or a bit more) and the slap it back on, this seems to loosen up all the old grease etc.

Long term it is probably good to follow the cleaning and greasing download from Shark1e, though personally i would used a little lithium grease rather than copper grease. As over greasing seems to cause as much trouble as none at all!