Characteristics of automatic MY AWD system

GunFactory · Post by **GunFactory** » Fri Dec 07, 2012 11:38 am

Hi all,

Does anyone have any links, or general info on the pro's/con's general workings of the MY automatic AWD system?

I'm generally just curious seeing that it lacks a centre diff etc - I'm not after super detailed schematics ect, rather a general outline and people experiences...

I have yet to take the car off-road since replacing the CV boots and adjusting the suspension so I literally have no idea what to expect. Something that got me thinking was the fact that I have two open diffs, does this mean if one wheel looses traction the car will simple spin that one wheel with the least resistance? how does not having a centre diff play into this etc.

I'm aware most people go for manual and dual range etc - just thought I would ask.

Yes I'm rambling but keen for any responses!

steptoe · Post by **steptoe** » Fri Dec 07, 2012 6:36 pm

was not AWD but 4WD and yep, spin wheel with least resistance. Had that in my L sedan and still got to impress some Toyota owners. Keep an eye out for a whole L series going cheap for 5 speed 4WD bits

Gannon · Post by **Gannon** » Fri Dec 07, 2012 7:11 pm

The 3 speed 4WD auto has constant drive to the front wheels, but when 4WD is selected, a hydraulic clutch pack transmits torque to the rear wheels.
Its either on or off, unlike the later 4 speed electronic auto of the Liberty (and very rare 4sp Vortex) that was able to vary the torque sent to the back wheels depending on throttle position and calculated wheel slip.

Post by **TOONGA** » Fri Dec 07, 2012 9:06 pm

this is the automatic transaxle section from the FSM for the ea81

https://www.rapidshare.com/files/666252 ... ission.pdf

the whole FSM is here

https://www.rapidshare.com/files/1310036760/ea81.rar

TOONGA

steptoe · Post by **steptoe** » Sat Dec 08, 2012 8:12 am

Gannon wrote:The 3 speed 4WD auto has constant drive to the front wheels, but when 4WD is selected, a hydraulic clutch pack transmits torque to the rear wheels.
Its either on or off, unlike the later 4 speed electronic auto of the Liberty (and very rare 4sp Vortex) that was able to vary the torque sent to the back wheels depending on throttle position and calculated wheel slip.

very rare Vortex AWD E4AT - I reckon the Oz delivered L Series GLTA with E4AT was rarer than the auto Vort - only seen one Lturbos, but seen lots of auto Vorts advertised

GunFactory · Post by **GunFactory** » Sun Dec 16, 2012 8:20 am

Sorry forgot to thank the contributors - Much appreciated!

Well I cant wait to go out and give it a bit of a go on the dirt!

Considering acquiring a pair of retread mud tyres (13 inch) they have been discussed on the forum before - sold by 'mudtyre_madness' on ebay.

I have picked up a pair of 13" sunnies figured they could serve as spares or with retreads maybe off road tyres/rims.

Is this advisable running two different sets of tread? and if so front or rear? - I was thinking rear.

Cheers

GunFactory · Post by **GunFactory** » Sun Dec 16, 2012 8:37 am

Im also curious as to the maximum tyre width that the factory sunnies can take? The rims look slightly wider..

Thanks

littlewhiteute · Post by **littlewhiteute** » Sun Dec 16, 2012 8:40 am

If one wheel is off the ground while in 4WD, the lack of centre diff still allows drive to the other 3 wheels.

Have a think about it.

Don't run different tyres (make or size) front and rear. Gearbox will windup in 4WD.

GunFactory · Post by **GunFactory** » Sun Dec 16, 2012 8:54 am

Right right - good to know! So if the two more 'off road tyres' were the same specifications but had more rubber on them - being newer and more chunky they would be unsuitable?

steptoe · Post by **steptoe** » Sun Dec 16, 2012 11:28 am

been blown away to compare the difference of two brands of pax car tyre of same spec, looked like 19mm difference in actual height !!

littlewhiteute · Post by **littlewhiteute** » Sun Dec 16, 2012 11:49 am

GunFactory wrote:Right right - good to know! So if the two more 'off road tyres' were the same specifications but had more rubber on them - being newer and more chunky they would be unsuitable?

My rule is for any 4WD or AWD is to run the same brand of tyre front and rear, all 4 tyres of the same tread depth.
Buy 4 from new and rotate often.

Brumby Kid · Post by **Brumby Kid** » Sun Dec 16, 2012 1:50 pm

littlewhiteute wrote:If one wheel is off the ground while in 4WD, the lack of centre diff still allows drive to the other 3 wheels.

Really? I would have thought that the wheel in the air would spin, and it's partner wouldn't.
Whilst the other two would spin making it 2wheel drive.
This is what happens in landcruisers.