Nissan Patrol 4x4 (Africa)

Hello!

I just have been to Marakele NP and also went to the 2000+ meter high viewpoint.
As that road is quite steepfor the way downward I had the idea to use 4x4L as I wouldn't have to go down in first gear as I would have needed in 4x2 / 4x4H.

So I stop, engage 4x4L and start going down using the engine to brake the car.
Suddenly I get a very loud and hard BANG, the 4x4 selector moved quite a bit then but stayed in 4x4L.
I immediately think, the drivechain for 4x4 did jump over. It happended a few times again (3-5 or so). Then I stopped, tried 4x4H with the same result.
The road was a tar road. So I changed to 4x2 and did the 1st gear thing...

The BANG only occured when not applying any throttle, as soon as I would use that, no more bang.

Later on sand I switched through 4x4 L, H, DIFF lock on and off - all seemed fine.

So initally I thought the drivechain might be worn out but then somehow got the idea that the auto hubs (always in the auto position) might be the bad guys.
I only use 4x4 very rarely and actually never had the opportunity to use it downhill for a longer period without thrust.

So what is your impression: would you rather suggest the hubs or something more serious?

Florian

It is not good to use the 4x4H or 4x4L on any tar road that is dry!

Agree with Kobus, but I would suspect the hubs first.

some things I can think of: - Rear propshaft universal joints; Loose suspension / coilsprings / pitman arm / CV' in front / loose EXHAUST [one of the rubber hangers likely / gearbox or engine mountings [or VERY SCARED Swambo in passenger seat ??? ]
On a Land Cruiser we had that on Van Zyl's Pass .. and it turned out to be CRACKED body work [A-pillar AND door pillar] [was very old cruiser]

Thanks for the replys.
That actually was something I wanted to add: I was not sure if you only must use 4x4 if the wheels can spin independently like on sand.

So it seems due to the chain drive you basically have a link between the front and aft axle and therefore must only use 4x4 when on loose ground. Is that correct?

That would explain the issue independently of the hubs.

Just grease up the slip joints on your props too they make a bang when they move ...put your hubs in manual lock with wheel spanner and have a look again

Florian320 wrote: therefore must only use 4x4 when on loose ground. Is that correct?.

Yes, correct.,... Only use 4wd on non- sealed surfaces ,... or you will end up with "diff wind-up",.. and possibly damage splines, ring and pinion, or more.

Thanks!
I should have looked that up before - I hope I didn't damage anything....

So I think it is solved - stupid user

Florian .. kein problehm .. Not to worry --
You CAN go in 4x4 on atarred surface if you do it the way you dit .. VERY SLOW in first gear.
On the open road at speed you may have problems with wind up and such

I would still look for that bang/klang/doefff sound source somewhere else though.

A loud bang from the transmission is commonly reported (if you look around the Web) when using four-wheel drive on hard surfaces – it is the transmission chain slipping on the sprockets. I would not do it as it really does not do the system any good at all. This is one of the disadvantages of having a part-time four-wheel-drive setup. In this type of context, permanent four-wheel-drive is far better.