4x4 Low Range gearing?

[Elliot]

So far my Playa vehicles have been pedal-powered, except one golf cart based. But the urge to build a larger "real" MV refuses to go away.

Mechanically, the concept is to use a pickup-truck chassis, with automatic transmission for easy stop-and-go. But I'm considering getting four wheel drive also. For one thing, it would be less likely to get stuck. But more importantly, it would have Low Range gears.

My experience with the golf cart based MV is that it goes too fast. To me, a MV rarely needs to go faster than two or three MPH. And many road-going vehicles will go over 5 MPH by just letting off the brake pedal. So I'm thinking the ideal thing might be to use Low Range on the Playa.

With Low Range, it might even be realistic to use a stick shift.

Thoughts? Experience?

[insomnivore]

A low range would be well suited for heavier applications that demand the additional torque, or applications that make use of very large tires. It would also be very useful if you plan on using a smaller engine (6 cyl. or even 4 cyl if you intend to use an older import chassis). The idea is to maximize mechanical advantage, but will usually keep you at a higher RPM, thus using more fuel. However, if you don't plan on having a lot of weight or other situation where the mechanical advantage is needed, you would likely be ok with just leaving it as is and setting up a governor system (block of wood under the gas pedal) to keep the speeds at a minimum. This keeps your RPM down and your fuel tank fuller longer.

my advice is, go for it and have the flexibility to choose. I've yet to make it to the playa so I'm not sure how much stop/go there is, or if turning radius is a big deal (4x4 affects it, slightly), so others will have to chime in on the playa particulars. Just make sure the front drivetrain is in good order as I imagine fine dust would play hell on u-joints, and if you buy a manual find one with a softer clutch. Too heavy a clutch with stop/go driving and you'll soon find yourself walking in circles.

[ygmir]

low range is great......but I'd not go a standard trans......even in low range, it'll idle at 5 mph or higher, unless you have super low gearing.......( one of my Jeeps is 5.20:1) and in compound low , it idles about 2 mph.
an auto trans, is the way to go.
the Stagecoach we have in camp is a Chevy S10 chassis, auto, not 4x4 and has done just fine......heck if it did somehow get stuck, you have a car full of folks to push you off the dune, anyway.

[Elliot]

...in compound low , it idles about 2 mph.

That's what I have in mind.

(And yes, auto trans for sure now that I think about it.)

I'm seeing quite a few 1990s full size 4x4/auto trucks (and Suburbans) on Craigslist for less than $2.000,-.

[ygmir]

...in compound low , it idles about 2 mph.

That's what I have in mind.

(And yes, auto trans for sure now that I think about it.)

I'm seeing quite a few 1990s full size 4x4/auto trucks (and Suburbans) on Craigslist for less than $2.000,-.

the other nice thing about the auto trans is no clutch.......with all the stop and go related to darkwads and general clueless (sure I see a 4 ton vehicle coming at me, but yeah, I'll step in front, I know he'll stop) people, it's so much better.
and then gearing is not nearly the issue, since the torque converter takes up rpm slack.
smoother take offs.....all in all, mucho bettero (yes, I am multi lingual)

[Elliot]

Yeah, that's settled; auto tranny on the Playa.

The more I look on Craigslist the more cheap 4x4s I see. Cannot hurt to have it, can it.

[ygmir]

Yeah, that's settled; auto tranny on the Playa.

The more I look on Craigslist the more cheap 4x4s I see. Cannot hurt to have it, can it.

I'm not the one to ask.....
I have 6 running and 3 in the process of getting running, all wheel drive (some are more than 4x4) vehicles.

[Elliot]

Yeah, but those military three-axle trucks might be too much of a good thing for me!

An amazing number of trucks with no title on Craigslist. Are people really that scatterbrained? Or are these all stolen?

Oh, I need to ask: Do all domestic full size 4x4s have a low range? Many sellers seem to be clueless about what they are offering for sale.

[motskyroonmatick]

I've never seen a pickup truck that was 4WD and did not have low range. I recommend getting a pickup with lockable hubs that can be set to free. That way you can select 4WD Low Range with the hubs in free and have super slow rear wheel drive only... that way there is no crow hopping when making turns.
I used to buck hay on to my truck and trailer with my truck driving it's self like that in granny low. I could walk up to it and turn the wheel a little through the window when needed. It was a manual transmission that had granny 1st gear. Low range gives a nice selection of close ratio gears. Keep us posted.

[Bob]

Cowboy Carl with the DPW has been known to let his truck idle along in compound low while building fence.

[Elliot]

Oooo yeah... I've been wondering if it would be possible to drive in Low with front hubs unlocked. That would be the perfect arrangement. No diff between front and rear on these things, eh?

Which brands and years have manual locking hubs? The photos people post rarely show enough detail.

Oh... an other thing I could do.... The downside to using an automatic tranny is that I cannot select my gear, which might be desirable in Low Range. But.... Automatics can be modified to shift manually -- drag racers do it all the time.

[FIGJAM]

You put it in 4low then shift the selector to the lowest gear.

What the hell have you been driving besides the bus?

[Elliot]

Never had a 4x4. My daily driver is a 2wd Dodge Dakota. Yeah, perhaps I'm overthinking the auto tranny. Those can be locked in 1st or 2nd from the factory, can't they....

Anyroad, skimming CL ads, it looks like Fords tend to have manual front hubs and Chevys not. That sound right?

[Tiahaar]

happy 4x4 hunting Elliot! I can add that older Dodges and Plymouths among others often had fulltime 4wd (yes there are Plymouth trucks, mine's a '76 Trailduster 4x4 model, mostly the same as the Dodge Ramcharger) with a 3rd diff in the transfer case. you can spot these as the t-case shifter will have hi-lock, hi, N, lo, lo-lock positions on it and there won't be front locking hubs (unless there's an aftermarket conversion). avoid the lock positions like the plague except for low traction situations and the hard smooth playa is really a pretty high traction surface... I wanna see what you come up with!

oh yeah I know those old rancher tricks on removing the (maybe broken) front or rear driveshaft and driving around in hi-lock or lo-lock...got me out of a bind here and there...

[FIGJAM]

That's true!

I know people who pull the front drive shaft to improve gas milage, then it would'nt matter if it had locking hubs or not.

[Elliot]

Makes sense. With full time four wheel drive you would need a center diff. And if it can be locked, you have the best of both worlds. But I'm also thinking in terms of availability and cost of parts and repair skills, and that narrows it to Ford and Chevy -- primarily Ford, the top pickup seller for decades, I believe. For example, I would want the automatic freshened by a pro before using it.

Now that you mention it, I've seen 4x4s driving around without the front drive shaft. But I would want locking hubs in case I get stuck in a Playa dune.

This isn't going to happen for a little while. It may even wind up being for 2013. But I want to educate myself in advance.

[FIGJAM]

On mine the autotrans shifter is on the collumn, and the shifter for thr transfer case is on the floor.

The trans indicater is the same as any vehicle.

The transfer case shifter is 2wd-nuetral-4high-4low.

Some vehicles are shift on the fly, which means you can put them in 4 high while moving up to 45mph.

Most require you to put the transmision in nuetral to shift the transfer case into 4x.

With the transfer case in 4 low and the transmision in 1st gear, engine idle will get you about 2mph.

Hope this helps Elliot.

Oh, that front drive shaft is short, and with the right wrench can be pull out in about 10 min.

Carry it in the vehicle and if you get stuck and need the 4x to get out, put it back in when needed.

[Elliot]

With the transfer case in 4 low and the transmision in 1st gear, engine idle will get you about 2mph.

Yep, that's exactly what I want.

[Mojojita]

And...you will have enough torque to pull a ginormous party barge through a lake full of peanut butter!

[Elliot]

And...you will have enough torque to pull a ginormous party barge through a lake full of peanut butter!

As a matter of fact, I hope to find one with a little six-cylinder engine. Definitely no need for more.

[inthecolumbiagorge]

We found this 87 Bronco II on our local Craigslist for $300, it runs like a champ, no major fluid leaks, lights and stereo works, 4 wheel drive works great and it goes right at 3-4 mph in 4 low. The previous owner even converted the air conditioner motor into an air compressor with a hose that will blow out the radiator perfectly and the tires are in good shape too. I think the playa gods could not have been kinder to us or found us a better base for an MV or handicap vehicle:-) Hope you are as lucky as we were!

[ygmir]

We found this 87 Bronco II on our local Craigslist for $300, it runs like a champ, no major fluid leaks, lights and stereo works, 4 wheel drive works great and it goes right at 3-4 mph in 4 low. The previous owner even converted the air conditioner motor into an air compressor with a hose that will blow out the radiator perfectly and the tires are in good shape too. I think the playa gods could not have been kinder to us or found us a better base for an MV or handicap vehicle:-) Hope you are as lucky as we were!

if there's already an oiler there excuse my assumption:

but,
if you're using an A/C pump for air, make sure you have an oiler, or way to oil it.
they are internally lubed from oil in the A/C system, and if pumping air, can and will run dry and break.

[inthecolumbiagorge]

We have not used the pump really for anything and have an air compressor anyway but I will let my husband know of your concerns regarding an oiler and thanks for the info!

[moltensteelman]

You can always add an under drive gear box, Klune extreme v drives have a 4 to 1 reduction for smaller vehicles and a 2.72: 1 for larger vehicles, these planetary gearboxes work well on both 4wd and 2wd vehicles. They may be a little pricey but bolt to the back of an automatic and offer plenty of torque and can be shifted from a 1:1 ratio to a gear reduction. I have two of these bolted back to back behind a 454 big block Chevy on The Walking Beast to give me a final drive ratio of 125:1. I have no problems keeping it under 5mph!

[Elliot]

Yes, I've seen your Beast walk! By the way, with your skills you "need" to get involved in the Kinetic Sculpture Race in Corvallis. We routinely run various forms of transmissions in series.

[moltensteelman]

@ Elliot
Da vinci days has been mentioned to me before, It might happen some day when I have fewer projects on my plate. Currently all my projects are electric or engine powered.
I beleive the kinectic sculpture race is for human powered vehicles.

[Elliot]

Correct. Strictly human power. But you can have as many people as you want. This is my most recent entry, with four people.

[Major Krash]

my first MV was a Jeep J-10 Gladiator pick-up (straight 6 4wd w/ granny gear). Worked great (until I blew a crank bearing pulling too much crap on the way down)

Granny gear was too slow, but it would idle in 1st gear at about 4mph and 2nd just under 10 (the speed limit back then was 10)....I would just steer, only braking to stop.

I think you are on the right track!

[moltensteelman]

@ Elliot
Nice machine, it looks like it would make a good MV as well if it doesn't take too much effort to keep it going. Are flywheels allowed?
I may have to check out the event this year.

[Elliot]

My aluminum pedal vehicle goes just fine on the Playa!



Flywheels have been a hot topic of discussion in KSR for several years. A few years ago a team used electric power transmission with giant capacitors, and that led to discussion of flywheels. There was some talk of an experimental class for such things. I think there was some concern about homemade flywheels disintegrating with harmful results. But you would have to check with the organizers. You should find them on the DaVinci Days web site.

Definitely check it out this year if you can; July 21-22, I think.