4 wheel drive - is it?

there was a company called fluid drive or summit, i had fitted these years ago, and could be operated by an electrical signal,it was a tourqe converter, or soft start system, however they were all to big to fit on a free lander prop system, shame as this would be the way to go, , ,i'm still looking

ianh1 said:

as there will always be some drive train wind up even if the front and rear diff ratios are identical!!

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I know I am slow on the uptake.... but how would you define drivetrain wind up.

It wouldnt be like a diff lock on defenders

Older range rovers use the VCU as well. I know it has been suggested before but placing the linkage on the front part of the prop and keeping the VCU is always an option.

There is a fair bit of play in the CV joint on the front Diff flange. If spline pattern from the inner part is retained and shortened in some way, then simple means of a locking pin (15mm diameter) moved by electromagnet or manually.

Real ones do it by using a 3rd diff in the rear drivetrain.
This can be locked in the same way that Ian is talking about to give drive to front and rear when the going gets tough but during normal driving slips to stop windup. I think the RR Classic had something similar to the Freeby but with identical ratios front and back. Brings me back to my original idea that they did it because FL is based on what was originally a 2wd design and it doesn't handle too good as 4wd at speed. If the ratios are the same the VC would only turn very very slowly. i don't know if this would affect its tendancy to seize though.

I'm pretty sure its exactly like running the Defender on good roads with the diff lock on the seized VCU is the same as the locked diff.

ianh1 said:

Re diff ratios -- have mused over it -- however I am sure I have seen somewhere in an earlier life (last year maybe on another site) that LR achieved the effect of minimising the difference between front and rear diff ratios, by altering the effective front diff ratio in the IRD !!!!

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According to ASHCROFT transmissions they have the new rear diff with stronger bearings, doesnt mention ratio of the diff:

Ashcroft Transmissions

If the slip is 0.8% am I correct in thinking that the slippage in 'degrees' on the VCU is 2.88 degrees slip in 360 degrees. Thst quite a lot

ming said:

there was a company called fluid drive or summit, i had fitted these years ago, and could be operated by an electrical signal,it was a tourqe converter, or soft start system, however they were all to big to fit on a free lander prop system, shame as this would be the way to go, , ,i'm still looking

Click to expand...

Keep up the search Ming us mortals are depending on it

Boxer said:

Brings me back to my original idea that they did it because FL is based on what was originally a 2wd design and it doesn't handle too good as 4wd at speed. .

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I have the prop off most months of the year, It handles fine in 2wd mode, a bit of understeer when wet but hey.....dont all front wheel drive cars do that.
Its just the roll of the cabin when cornering at speed, this could be sorted with an upgraded suspension, better dampers, polybush kit etc, lower profile tyres

still lookin - but here is summat to confuse yu guys......


System Description
ELECTRIC CONTROLLED COUPLING
Operation principle
1. 4WD control unit supplies command current to electric controlled
coupling (4WD solenoid).
2. Control clutch is engaged by electromagnet and torque is
detected in control clutch.
3. The cam operates in response to control clutch torque and
applies pressure to main clutch.
4. Main clutch transmits torque to wheels according to pressing
power.
_ Transmission torque to rear wheels is determined according
to command current.

4WD CONTROL UNIT
_ Controls distribution of drive power between front-wheel drive
(100:0) and 4WD (50:50) conditions according to signals from
sensors.
_ Self-diagnosis can be done with CONSULT-II.

ALL MODE 4X4 SYSTEM
4WD MODE SWITCH
AUTO mode
_ Electronic control allows optimal distribution of torque to front/rear wheels to match road conditions.
_ Makes possible stable driving, with no wheel spin, on snowy roads or other slippery surfaces.
_ On roads which do not require 4WD, it contributes to improved fuel economy by driving in conditions close
to front-wheel drive.
_ Sensor inputs determine the vehicle's turning condition, and in response tight cornering/braking are controlled
by distributing optimum torque to rear wheels.
LOCK mode
_ Front/rear wheel torque distribution is fixed, ensuring stable driving when climbing slopes.
_ Vehicle will switch automatically to AUTO mode if vehicle speed increases. If vehicle speed then
decreases, the vehicle automatically returns to direct 4-wheel driving conditions.
_ LOCK mode will change to AUTO mode automatically, when the vehicle speed exceeds approx. 30 km/h
(19 MPH). The LOCK indicator light keeps illuminating.
NOTE:
If there is a significant difference in pressure or wear between tires, full vehicle performance is not available.
Tire conditions are detected, and LOCK mode may be prohibited, or else speeds at which LOCK mode is
enabled may be restricted.
2WD mode
Vehicle is in front-wheel drive.
NOTE:
_ If front wheels are slipping in 2WD mode, do not switch to AUTO or LOCK. This can cause difficulties for
the system.
_ Even if the 4WD mode switch is in 2WD mode, the 4WD control unit occasionally automatically change to
AUTO mode depending on the driving condition (For example; Depressing the acceleration firmly). This is
not malfunction. However, 4WD indicator lamp dose not illuminate.

wots that orft then flops? the ford exploder had a very good system an electric switch poss 1=2wheel drive 2=wet roads 3= snow 4=mud un ****e , trouble was it was crap orft road. . .

yu can guess Minge, its my slitty X-T