rear wheel drive?

poprock1 · Post by **poprock1** » Mon Dec 13, 2010 9:51 pm

Firstly; apologies to Alex of Kellyville Ridge; the head teller said no to my intended purchase. My query is: If the main gearbox is in neutral, will high & low range still provide drive to the rear diff only? You may remember that I fitted an electric motor direct drive to the diff but it was too high to take off from standstill. I have since fitted the electric in place of the motor and it worked better but still limited by s/h batteries and no funds. 60ks top speed but the volts died too quickly. So I re-fitted the motor and this time plan to have the electric motor connected to the diff as before and to the gearbox as well. So the electric will work as a hybrid in 4wd : getting the throttle setting even will be an issue but will give a power boost (think Camry ad). So will it give rear wheel drive only in neutral with 4wd engaged? I have seen the posts from the Brumby owner wanting to drift with rear wheel drive only. Mission Impossible?

YouTube · Post by **El_Freddo** » Mon Dec 13, 2010 10:15 pm

No - but what you've said doesn't work.

To make a brumby rear wheel drive you need to remove the front drive shafts and run the gearbox in 4wd. This will still spin the front diff when you move off the line. You will loose the 4wd option with this.

The trick is to keep the outer shaft section that holds the front hubs together. This is how they do it.

So having your gearbox in neutral and 4wd will give no power to any of the wheels, it has to be in a gear to have drive to the wheels...

hope this makes some sense.

Cheers

Bennie

subarubrumby · Post by **subarubrumby** » Tue Dec 14, 2010 9:49 am

yeah, this weeekend i will get videos of me drifting the industrial estate roads so youse can see how good it goes, but keep in mind it is stock standard i plan to drift it after high tourqe cams, brass button or heavy duty clutch, stiffer springs in the front, 32/36 carby with head shaved ported etc and also hyrdaulic hand brake to the rear so it will have a lot more gruntt and tourqe

tex · Post by **tex** » Tue Dec 14, 2010 9:57 am

Have you considered using a 2wd box for the engine and running the elec. motor off where the tail shaft goes, you may want to get a centrifugal clutch for it or a splitter/overdrive with one of the gears removed so you can engage or disengage the elec motor as you choose!

tex · Post by **tex** » Tue Dec 14, 2010 10:08 am

Sorry I just re read your post, I'd try a diff splitter between the motor and your diff and maybe borrow a 4.11 setup to see how it works. I've driven a twin engined scraper before and always been warned not to have more throttle on the rear engine than the front when cornering as the front is trying to slow you down and the back speed you up. I don't know how this pans out in cars but scrapers it doesn't work so it may be worth being mindful of this until you get used to it!

poprock1 · Post by **poprock1** » Tue Dec 14, 2010 5:52 pm

If the transfer case is in hirange 4wd and the elec motor is connected in series to both gbox and diff, (3.7:1) ; then we have a true hybrid with the elec as a power boost. What is the safest road speed and for how long without damage to the tranny?:(

YouTube · Post by **El_Freddo** » Tue Dec 14, 2010 6:10 pm

Ok - my mind just went hazy as I'm no longer following what you hope to achieve...

Got a drawing you can use paint to display on here to help us (me) better understand what you're trying to do?

Cheers

Bennie

poprock1 · Post by **poprock1** » Tue Dec 14, 2010 8:52 pm

If the pics come thru you will see the elec motor bolted to diff. If a shortened tailshaft is fitted to the front of the elec and to the rear of the gearbox this is the same as the original drive.So how fast and how long in 4wd high? This gives 4wd with elec boost like the Camry hybrid; or it can be fwd petrol or rwd electric.The elec motor is DC series so it doesn't matter if it freewheels when in fwd

Point · Post by **Point** » Tue Dec 14, 2010 11:51 pm

the problem is that there is no centre diff. It should work the same as it did with just a straight tailshaft, ie. don't engage 4wd on hard surfaces. I guess that with the box in fwd you could still add some extra drive from the electric motor to the rear wheels. Also, if you had the box in neutral and 4wd engaged, it will drive all 4 wheels, but then you're back to the problem of no centre diff. Hi/Lo in this case has no bearing on anything as the drive you are applying from the electric motor is past the low range gearing.

poprock1 · Post by **poprock1** » Wed Dec 15, 2010 7:08 am

Point wrote:the problem is that there is no centre diff. It should work the same as it did with just a straight tailshaft, ie. don't engage 4wd on hard surfaces. I guess that with the box in fwd you could still add some extra drive from the electric motor to the rear wheels. Also, if you had the box in neutral and 4wd engaged, it will drive all 4 wheels, but then you're back to the problem of no centre diff. Hi/Lo in this case has no bearing on anything as the drive you are applying from the electric motor is past the low range gearing.

I think that what I was wanting to hear is" Also, if you had the box in neutral and 4wd engaged,IT will drive all 4 wheels". The "IT" is the electric motor? I assume that the centre diff is sort of LSD to distribute drive to all wheels equally?

Point · Post by **Point** » Wed Dec 15, 2010 9:21 am

yeah, 'IT' would be the electric motor.

I just had a second look at the photos. Looks like an 'L' series?

the centre diff is to allow the front and rear wheels to turn at different speeds while cornering. The problem is, you don't have one. So if you engage 4wd while on bitumen and try to turn, the whole drivetrain will bind up. Your tyres will scuff and chirp, it will be hard to turn, and eventually you will probably break something.

tex · Post by **tex** » Wed Dec 15, 2010 11:05 am

Point wrote:yeah, 'IT' would be the electric motor.

I just had a second look at the photos. Looks like an 'L' series?

the centre diff is to allow the front and rear wheels to turn at different speeds while cornering. The problem is, you don't have one. So if you engage 4wd while on bitumen and try to turn, the whole drivetrain will bind up. Your tyres will scuff and chirp, it will be hard to turn, and eventually you will probably break something.

unless you remove one of the half shafts from the back!
Do you want to use the wagon in 4x4 otherwise i can't see why you wouldn't use it as its set up now! Also you can use the gearbox in 4x4 as long as you want even on the bitumen while you don't have the tail shaft connected you just need to stop the oil coming out the rear seal where the tailshaft would normally sit!

poprock1 · Post by **poprock1** » Wed Dec 15, 2010 11:47 am

Ok, I c da lite.constant 4wd on hard surface not recommended, something will break. Is currently without rear driveshaft except for stub shaft in rear of gbox. No seeable advantage to linking elec to gbox. other than using 4wd. Clutch disconnect required for normal road use if they are linked. I had it running in fwd only with elec to the rear with 2 acc pedals. Not enough power to cause problems as in the Scraper mentioned. Will return to this setup and ponder future . First I will obtain a s/h tailshaft to connect g/box elec in series. Watch this space!

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