NX: Clunk then sudden gain of traction in sand

[zoiks]

Evening,
Recently went to Fraser and apart from the weed, wind and torrential rain it was a good time.

Something I have noticed however and have noticed it before at teewah is that when driving in 4H and getting to a bit of sand that bogs you down I am hearing a Clunk (I think from the rear?). Its kinda like the Clunk you get when moving the car in to D or R sometimes .No lights come on from what I see but all of a sudden I get an increase in traction. It's like suddenly it's engaged a set of wheels.

Not sure what it is but I'm worried that something is slipping and suddenly coming into place.

Auto 2014 NX GLS. Happens in 4H and maybe in 4HLC.

Any ideas?


Also, probably unrelated I have noticed in 2H if I'm coasting and lightly accelerate I hear a small knock from the rear.

[mckenzl]

My NS does the same thing, it really does feel like another set of wheels engaging. I think it is changing from 2nd gear down to first. Happy to be corrected.

Liam

[spot01]

Auto or manual?

Are you using 4H or 4HLC?

[zoiks]

My NS does the same thing, it really does feel like another set of wheels engaging. I think it is changing from 2nd gear down to first. Happy to be corrected.

Liam

I never thought of that.
Perhaps it could just be an 'under load' change. But should changes really make that much noise?

Auto or manual?

Are you using 4H or 4HLC?

Auto. I know it happens in 4H but I swear its happened in 4HLC before.

[mckenzl]

Auto or manual?

Are you using 4H or 4HLC?

Both. Not sure in 4LL as I try not to use it unless it is really needed. Seems to happen when you start loosing a bit of traction and speed when going up a sandy hill for me.

Liam

[spot01]

I never thought of that.
Perhaps it could just be an 'under load' change. But should changes really make that much noise?



Auto. I know it happens in 4H but I swear its happened in 4HLC before.

In 4H it may be the centre diff locking up after you loose traction - I believe it is a fancy viscous unit similar to that used in the Lancer EVO rally cars that can vary the amount of drive it sends to the front & rear axles as needed - unsure about the noise though? Perhaps try using 4HLC (or 4LLC) in sand to see if the issue continues - this will also put less strain on the drivetrain & usually gives better results.

[conquistador]

Evening,
Recently went to Fraser and apart from the weed, wind and torrential rain it was a good time.

Something I have noticed however and have noticed it before at teewah is that when driving in 4H and getting to a bit of sand that bogs you down I am hearing a Clunk (I think from the rear?). Its kinda like the Clunk you get when moving the car in to D or R sometimes .No lights come on from what I see but all of a sudden I get an increase in traction. It's like suddenly it's engaged a set of wheels.

Not sure what it is but I'm worried that something is slipping and suddenly coming into place.

Auto 2014 NX GLS. Happens in 4H and maybe in 4HLC.

Any ideas?


Also, probably unrelated I have noticed in 2H if I'm coasting and lightly accelerate I hear a small knock from the rear.

The rear diff locating bushes could have perished which is more likely to account for a faint knock or thud you described in 2h. Generally putting it into 4h would stop or dull this.

Given the above might be that on a high drag surface like sand any abrupt gearbox or viscous centre diff responses might amplify it.

My gearbox will take a deep breath sometimes in a high slip second gear hill climb and drop strongly/positively/abruptly into 1st. Can feel like a slingshot.

[zoiks]

The rear diff locating bushes could have perished which is more likely to account for a faint knock or thud you described in 2h. Generally putting it into 4h would stop or dull this.

Given the above might be that on a high drag surface like sand any abrupt gearbox or viscous centre diff responses might amplify it.

My gearbox will take a deep breath sometimes in a high slip second gear hill climb and drop strongly/positively/abruptly into 1st. Can feel like a slingshot.

Would the locating bushes be something covered by drive train warranty? If not any idea how much something like this would cost to replace?

Ill have to go for a drive on the beach sometime and listen out for the knock and corresponding rise in revs as it drops a gear. If its normal to make that noise, it's ok. Just do not want to be damaging anything.