Loose drive when wheel is in air

[tyspsi_v6 Lurker Find all posts View Profile Close tyspsi_v6]

Hi all,
I have bought the missus a 06 V6 120 serries Toyota Prado, I love it and enjoy driving it. Last weekend i went a had a play in it and noticed that as soon as you picked up a wheel... which isn't hard in an ifs truck all drive would be sent to that wheel in the air. Should this happen or should i still have drive out of the front wheels? I know it hasn't got lockers but you should get drive from at least one front wheel and one back wheel with open diffs and a locked transfer case... All help is appriciated
Cheers Ty

[FlyingBushPig Advanced Member Find all posts View Profile Close FlyingBushPig]

Re: Loose drive when wheel is in air

As long as you have traction on all four wheels you will have "four wheel drive". As soon as you lose traction on a wheel, all power from the drive train to that part of the vehicle (e.g. front drive train) will immediately go to the place of least resistance - which means in your case, the wheel which is in the air. The wheel still on the ground wont receive any power and acts simply like a trailer wheel (all it's doing is keeping the vehicle off the ground).

If both wheels at the back are still on the ground (and have traction), you will still have forward movement as the power is distributed between the two. If both a wheel at the front and wheel at the back are off the ground (or spinning for any other reason), your other wheels on the ground wont move forward at all.

Lockers fix this issue by locking the differential so power goes to both wheels equally regardless of whether one has lost traction.

So...you should get power to at least one wheel if the transfer case is locked.
If one wheel was off the ground and the other was spinning in mud/sand etc then you should lose momentum. Are you sure you locked the centre diff?

[samo Addicted PP Member Find all posts View Profile Close samo]

Re: Loose drive when wheel is in air

phil is right on the money there, with the centre diff unlocked it will allow slip between the front and rear axles, great for driving on tar and hard surfaces where wheel slip is non exsistant, with it locked it will allow no slip, even though it has a limited slip rear diff, (in toyotas case it should be a limited drive diff) they make a pretty poor lsd ie it doesnt have enough preload on the lsd to give a decent amount of drive to the wheel that as all the grip. An lsd will only work if both wheels on that axle r in contact with the ground, with a wheel in the air it is vertually a std diff, a little trick is to apply a little handbrake when the wheels r spinning to trick the lsd into thinking it has traction on both wheels, it will work to a point but its no locker, you r doing the right thing, get out there and have a play, learn to know what your ride can do and work out how the driveline works when centre diff is locked and unlocked, lockers r great but they come at a cost, and remember when if you purchase a locker you do away with your lsd center in the rear and it becomes a std diff when unlocked, but when you flick that little blue switch yo have 100% lock up on that axle. hope this helps. cheers samo

[tyspsi_v6 Lurker Find all posts View Profile Close tyspsi_v6]

Re: Loose drive when wheel is in air

Thanks for your replys... I think i am locking the transfer case by selecting LL on the short stick... or do you have to have a centre diff lock button to lock the transfer because my Prado doesn't. I agree with what you have said about lockers giving you 100% traction, I have two on my Hilux. For example if I don't lock the lockers on the Hilux and lock the transfer case i will always get drive from at least one front and one back wheel. But in the case of the Prado on the weekend I only got drive from the back wheel. I have a pic of the exact situation... however i don't know how to insert pics on this forum... but if you go to this link http://www.4wdmonthly.com.au/forum/show ... 243&page=7 you can see the image of the Prado its picture number 2

[ozwapet2 Advanced Member Find all posts View Profile Close ozwapet2]

Re: Loose drive when wheel is in air

An auto Prado should have a button to engage CDL, on a manual my understanding is it engages when you go into low ( check the user manual ), Whatever, the light on the dash will come on when CDL is locked.
Sounds to me like you had the typical situation i.e centre diff locked, front wheel off the ground, therefore no drive from front due to open front diff, rear wheel slipping in the gravel, LSD can't cope.
There are two ways to overcome this - lockers or traction control.
Lockers are the ultimate option, but I would guarantee traction control would have gotten you out of the situation you describe. This would have braked that spinning wheel in the air and given you traction on the other wheel.
- unfortunately it is only a factory fitted option.

[tyspsi_v6 Lurker Find all posts View Profile Close tyspsi_v6]

Re: Loose drive when wheel is in air

No there is no CDL button but the light is on the dash when i selected LL. Also the front wheel wasn't off the ground only the back have a look at the pic at the link http://www.4wdmonthly.com.au/forum/show ... 243&page=7 its the second picture.

An auto Prado should have a button to engage CDL, on a manual my understanding is it engages when you go into low ( check the user manual ), Whatever, the light on the dash will come on when CDL is locked.
Sounds to me like you had the typical situation i.e centre diff locked, front wheel off the ground, therefore no drive from front due to open front diff, rear wheel slipping in the gravel, LSD can't cope.
There are two ways to overcome this - lockers or traction control.
Lockers are the ultimate option, but I would guarantee traction control would have gotten you out of the situation you describe. This would have braked that spinning wheel in the air and given you traction on the other wheel.
- unfortunately it is only a factory fitted option.

[ozwapet2 Advanced Member Find all posts View Profile Close ozwapet2]

Re: Loose drive when wheel is in air

Oops sorry - oh well, same diff ( excuse the pun )

[Guest Close Guest]

Re: Loose drive when wheel is in air

Does traction control still work when VSC is off, ie when in low range and I engage the CDL in my Grande?

[MickL Addicted PP Member Find all posts View Profile Close MickL]

Re: Loose drive when wheel is in air

Does traction control still work when VSC is off, ie when in low range and I engage the CDL in my Grande?

Yes

Ty,

Looking at your pic this is pretty normal for a Toyota... the LSD's are more slip than grip. A little handbrake to load the LSD would have seen you keep moving forward.

Mick

[tyspsi_v6 Lurker Find all posts View Profile Close tyspsi_v6]

Re: Loose drive when wheel is in air

In that pic the front wheels were not turning at all... thats what I'm getting at

Does traction control still work when VSC is off, ie when in low range and I engage the CDL in my Grande?

Yes

Ty,

Looking at your pic this is pretty normal for a Toyota... the LSD's are more slip than grip. A little handbrake to load the LSD would have seen you keep moving forward.

Mick

[MickL Addicted PP Member Find all posts View Profile Close MickL]

Re: Loose drive when wheel is in air

In that pic the front wheels were not turning at all... thats what I'm getting at

Ah OK, I miss understood. If spinning one wheel stops you then your centre diff lock is not engaged.

If it's engaged you need to lift two (opposite corners) to bring you to a halt.

Did you just engage it as you drove up that mound? Sometimes you have to drive a fair few meters before it locks properly (despite the light coming on) and vise versa when unlocking it... sometimes it takes a few meters of motion to get it to drop out.

Or it could be it just needs a few lock/unlocks to get it going again (maybe the previous owner never engaged it ??)

Hopefully the previous owner didn't break it for you!


Mick

[tyspsi_v6 Lurker Find all posts View Profile Close tyspsi_v6]

Re: Loose drive when wheel is in air

Could it be a fuse or something because it was engaged for a while before taking on that mount.

In that pic the front wheels were not turning at all... thats what I'm getting at

Ah OK, I miss understood. If spinning one wheel stops you then your centre diff lock is not engaged.

If it's engaged you need to lift two (opposite corners) to bring you to a halt.

Did you just engage it as you drove up that mound? Sometimes you have to drive a fair few meters before it locks properly (despite the light coming on) and vise versa when unlocking it... sometimes it takes a few meters of motion to get it to drop out.

Or it could be it just needs a few lock/unlocks to get it going again (maybe the previous owner never engaged it ??)

Hopefully the previous owner didn't break it for you!


Mick

[GeeBee Lurker Find all posts View Profile Close GeeBee]

Re: Loose drive when wheel is in air

You can lock the center diff by pushing the little stick forward just a little, still in H but center locked, light on dash will come on, then if you push it forward more you will get neutral and then more and you will find low and center lock, light will be on dashboard.

[StormyKnight Advanced Member Find all posts View Profile Close StormyKnight]

Re: Loose drive when wheel is in air

Yes the CDL (Center Diff Lock) light has to be on....it comes on when the actual center diff is engaged, not just when the lever is in position. Sometimes you have to drive a bit as both shafts need to line up before it will engage..but no light no locked center diff.


With the CDL locked 50% of your drive will go forward & 50% rearward, the same as you Hi-Lux in 4WD.

[hassro Junior Member Find all posts View Profile Close hassro]

Re: Loose drive when wheel is in air

I have a 2003 Grande how do I tell if it has traction control? I did a driving day a couple of weeks ago and a 150 climbed hills with ease but my car seemed to stuggle although I think my tyrepressures were way to high about 38psi.