No 4WD

jgm · Post by **jgm** » Mon Jan 21, 2008 10:09 pm

Following on from my previous thread.....

My 4WD isn't working.

I've just been out observing what spins with all 4 wheels on ice. One rear wheel and that is it. There are front driveshafts and a propshaft from the front diff disappearing into the plastic covers - too dark and cold and wet for any further investigation.

Anyone had this problem before?

thanks

John

dandywarhol · Post by **dandywarhol** » Mon Jan 21, 2008 10:18 pm

.......therefore it hasn't got a limited slip diff (some haven't it seems) so it's doing all it can do - it's sending all it's torque to the "slippiest" wheel.

The Bongo 4WD system's pretty crude - if the surface is all ice/snow then you're stuck - you need some form of grip somewhere for it to transfer some torque to the front.

Sounds to me like it's doing as best as it can for a viscous coupled "4WD"

jgm · Post by **jgm** » Mon Jan 21, 2008 10:24 pm

dandywarhol wrote:.......therefore it hasn't got a limited slip diff (some haven't it seems) so it's doing all it can do - it's sending all it's torque to the "slippiest" wheel.

The Bongo 4WD system's pretty crude - if the surface is all ice/snow then you're stuck - you need some form of grip somewhere for it to transfer some torque to the front.

Sounds to me like it's doing as best as it can for a viscous coupled "4WD"

I understood that drive was transmitted to the front wheels when there was a difference in speed between the front and rear propshafts, therefore I would have expected a worst case to be one front and one rear wheel spinning - or am I misunderstanding something here?

thanks

John

Ralph · Post by **Ralph** » Mon Jan 21, 2008 10:29 pm

Surely if it's working ok it should spin one rear and one front
at least? unless the chain in the transfer box viscus cupelling
or front dif are ca-put it's got to drive one front one back.
Even on ice ours bonds away with a fare bit of enthusiasm

dandywarhol · Post by **dandywarhol** » Tue Jan 22, 2008 12:08 am

Yes, you're both right, the drive goes straight out the transfer box to the rear propshaft and along the chain to the front propshaft via the VC.

Sounds like it's not getting drive past the VC then - or as Ralph says, the chain isn't connected.

DemonAV · Post by **DemonAV** » Tue Jan 22, 2008 9:40 pm

Hi jgm
I think you need verify your 4WD system.
It's easy.
You need to raise one (any) front wheel and with the help of dynamometer key turn it on 90 degrees with a force of 59 Nm or 6.0 kgf-m. If the turn of 90 degrees must be 30 seconds or more than viscus sleeve work. Another case change viscus sleeve (number 27-580 in the picture above).

jgm · Post by **jgm** » Tue Jan 22, 2008 10:40 pm

DemonAV wrote:Hi jgm
I think you need verify your 4WD system.
It's easy.
You need to raise one (any) front wheel and with the help of dynamometer key turn it on 90 degrees with a force of 59 Nm or 6.0 kgf-m. If the turn of 90 degrees must be 30 seconds or more than viscus sleeve work. Another case change viscus sleeve (number 27-580 in the picture above).

Thanks for that. Supplying dealer has said "oh I've seen lots like that, the previous owner has disconnected the front drive". When the snow has melted I'll stick it on a ramp and have a look and if I see nothing obvious then I'll try the torque wench test.

cheers

John