wouldn't that be almost like driving with your emergency brake on?

Gary,

You have to look at it from the input (drive line) instead of the output (wheels).

What happens is the front end gets turned slightly faster by the drive line where the rear end turns slightly slower.

The front and rear drivelines try and turn at the same speed so the front end will turn 4.11 times with 1 full rotation of the drive line where the rear turns only 4.10 times with 1 full rotation of the driveline.

Thus the front is pulling the rear end because it has rotated 0.01 times farther.

Logansportage <img src="/forums/images/graemlins/patriot.gif" alt="" />

The 1995-2002 do not have center differentials that is why we do not use the 4x4 on dry pavement. <img src="/forums/images/graemlins/zombie.gif" alt="" />

gary, sorry, thought we were talking dana 44 to dana 44 in different makes and models or from different gear manufacturers, not totally apples and oranges.

ryan, here's the thing... why do you want to be in front wheel drive so badly. there is a reason fullsize trucks come with a beefier rear axle than front, even Jeeps do, with their 30/35 combo. there is a reason for this. the reason is, if you're gonna break something, let the front go first, that way, you can still drive home on the rear. this is why the rear is usually stronger. now, if the rear is stronger, wouldn't you rather it take the brunt of the strain to the drivetrain? then why front wheel drive?

lastly, if for some unforseen reason, you have no wheel slip wherever you're running this difference in gear ratios, that .01 can still add up to enough to blow a t-case chain. see, the path to the front diff goes through the chain, while the path to the rear diff does not, making that a point of weakness for the front drive train.

4.11 to 4.10 will not be enough difference, probably, for you to even notice that there is a difference at all, however, arguing that it's somehow superior to have the front pulling the rear when you're at a 45 degree angle on rock steps 2 foot tall each and 3 more to go, is like using grade 2 bolts to hold your winch on in a 6000 lb pull. the steering axle should never have more pull than the non-steering axle, after all, what's the use in a big chevy truck running a 14 bolt rear along with that 10 bolt front? may as well have a 10 bolt out back too, because the front is still gonna break first.

Dave,

Answer me this. Would you rather be driving a rear wheel drive car or a front wheel drive car when traction is limited such as snow/ice or mud/dirt?

A front wheel drive car. This is why having the front end turn slightly faster in a 4wd setup is better.

Having a bigger rear end makes perfect sense because 80-90% of every day use is done with the rear end only. How often do you have your t-case engaged? 10%-20% of the time? And this is probably only when traction is limited enough that youÆre getting slipping on the rear end.


In your analogy I would rather blow up the rear end instead of the front end. If I blow up the rear end I still have the ability to drive and steer. If I blow up the front end there is a MUCH greater chance there could be steering failure too rendering me completely stranded.

Having the front end pulling by a small fraction such as 4.11/4.10 is not like using grade 2 bolts to hold your winch on in a 6000 lb pull. It isn't any different than driving your vehicle backwards in 4wd.

Most t-cases split power 40-60 front to rear. Try this. Put your vehicle in 4wd low range and romp the gas on a loose dirt road. You'll notice it'll start to get a little sideways if you hold the steering wheel straight. Now do the same thing, but in reverse. You'll notice it stays nice and straight. This is because the rear is getting more power (turning faster) than the front because of the 40-60 split. Thus pushing the car when going in forward and pulling the car when going in reverse.

ThatÆs why a slightly faster spinning front end would be better because it will put the split back closer to 50-50.

Logansportage <img src="/forums/images/graemlins/patriot.gif" alt="" />

Your logic about the front pulling is correct, but the ratio logic isn't. Re-read what I said earlier. The error in your logic is here:



The differentials are not stepping up the speed, they are stepping it down. The easiest way to look at it is from what you put in, to what you get out.

Put one turn on each driveshaft and "measure" how far you go. If you accept the logic of my 1:1/100:1 example then extrapolate down to 4:1/5:1, then to 4.1:1/4.11:1, the 4.11 takes more "turns" of the input shaft (driveshaft) to go the same distance as a 4.1, and so the 4.11 is the "slower" ratio.

All part time transfer cases split the torque 50:50. The only ones that dont are the ones with clutch packs and other "active" parts in them such as differentials. The Sportage has none of this, and is strictly "old school" part time using gears for low range reduction and a chain to link the front and rear driveshafts.

hey, man, i hate to keep bustin your balls, but you got this all the fk wrong. the Sportage t-case is 50/50, not 40/60. in fact, the only t-cases that allow any slipage between front and rear are full-time 4wd, all wheel drive and some Mitzu Montero cases where they thought that was a good idea. also, some Nissan Pathfinder cases have a viscous coupler, but i don't know if that is prior to the case or at the front out put. either way, the vast, vast majority of t-cases in 4WD rigs (not counting AWD) are 50/50 old skool tech. as it should be.

as far as what i'd rather have driving me in ice, snow and mud? here is my list:

mud- all 4 same time, same speed, period.

snow- on road, wouldn't know, off-road- same as mud

ice- well, if i can help it, i just wouldn't leave the house that day, but if not, i'd just drive very carefully in 2wd and coast a lot, slowing down way before intersections and curves, generally being careful. i guess the same would go for snow on the road, being that it turns to slush and ice. driving on ice is taking you life in your hands no matter what tires, no matter what drivetrain and no matter what experience you may have.

high water crossings- on road, rear wheel drive, off-road- all 4, same time, same speed.

generally, off-road, i want the rear pushing for the above mentioned arguments and i just think it has a better chance of getting me up that dust covered rock ledge without breaking. now, since it's 50/50, they are both moving, but when the front end is pointed at the sky, all the weight is on the rear, the front just spins while the rear climbs.

my t-case is never, ever engaged on pavement. however, as soon as i leave the pavement, it gets shifted into 4-lo. period, no compromises. i'd say that's about 40% of it's driven time, these days, miles will prolly put it at around 10%, but who's counting miles when it takes you 3 hours to go 1.5 of them?

in a front axle, especially and straight axle, you still have plenty of ability to steer if you break a front axle shaft. you can do 3 things to make it so- UNLOCK THE HUB, no steering problems because the broken axle is not moving, or remove the front shaft in unit bearing or full-time 4wd vehicles.

and ps- it's very different from driving your vehicle backwards, if you take into account the ring and pinion gears being directionally cut, weight differences and suspension travel differences between front and rear and the fact you only get one reverse gear in most consumer vehicle transmissions.

to reiterate: front axles are inherently weaker axles due to the steering joints, lopsided axle shaft lengths, locking parts and most being driven on the coast side of an R&P set. they should never take the grunt abuse usually reserved for a rear axle.

[quote][quote]Dave,

Answer me this. Would you rather be driving a rear wheel drive car or a front wheel drive car when traction is limited such as snow/ice or mud/dirt?

This is because the front cuts a path so the rear more easily rolls through,

**BS. It's because the rear is being pulled in the same direction the front just went.**

but mainly because a fwd vehicle has all the weight over the driven wheels,

**So does every thing else but your VWs.**

if your theory were correct i could take a rwd s-10 and drive in reverse and be fine, but try this in the winter and it won't help,

**I've done this and it does help.**

but if you had the same weight over the rear that you normally do in the front it would drive just fine,

**No it doesn't. It drives like a snow machine. If you have the front wheels turning then they grip and pull you in the direction you are steering.**

that and drop the air pressure down slightly ;-) I personally would rather have a rwd with weight because you have more control and can use the engines power via torque steer to aid in my control of the vehicle.

Logansportage <img src="/forums/images/graemlins/patriot.gif" alt="" />

Dave,

No balls busted here. It's an open discussion forum.

Can't see why you need to take into account the ring and pinion gears being directionally cut. If the gears are the same ratio then they should have the same directional cut and should operate the same.

Weight differences and suspension travel differences between front and rear may have something to do with it. But the same thing happens to IFS and solid axel, so I think Steve might be right here that torque steer might be the culprit. But then again wouldn't you get torque steer in the opposite direction when performing the test in reverse? This doesn't happen. The vehicle goes straight.

The fact you only get one reverse gear is irrelevant.

Not sure why this happens, but going to do some more research in the Sportage in 4 lo and 4 high especially this winter in the snow.

Logansportage <img src="/forums/images/graemlins/patriot.gif" alt="" />