The gear ratio for the front and rear are usually off by .01. Therefore it IS gonna bind some. It is designed that way to "pull" through mud and snow

 

"Usually" or "designed that way"??? In all my experiences with building and using 4x4 trucks I've never heard such a thing.

Not sure what ratio(s) you're running, but mine has 3.73 gears in the front and 3.73 in the rear...not 3.72 and not 3.74.

 

It is certainly done on tractors and possibly other four wheel drives. From a Detroit Locker owners manual:

"Overrun Ratio - On unequal wheeled four wheel drive tractors the transmission is so geared that any difference in road speed of the two axles results in a faster speed for the front wheels (lead or overrun), this prevents the front wheels from being pushed."

 

Unequal wheeled tractors are not exactly comparable to a 4x4 truck designed for road use. Apples to oranges as they say.

Having the front tires spin faster at 60mph on a snow covered highway would not work out too well.

 

Don't be too sure. Slightly numerically lower ratios in front than in the rear isn't limited to farm equipment, or to equipment with unequal tire sizes. I think you will find a lot of military equipment is or was this way, and so were some older 4x4s.

 

I could see it on any vehicle that isn't designed for long-term road use. I've still never seen or heard of a civilian truck manufacturer doing it (intentionally...lol).

I do know that it definitely isn't done like that on Toyota and Dana axles. Otherwise the front and rear ring and pinions would be different part numbers...and they're not.

 

Actually, some pickups have the same ratio and some don't, my 1975 ford as well as my dads 76 ford both have 4:11 in rear and 4:10 in front, the front spins ever so slightly faster than the rear. If somebody is driving one of them in 4 and if i watch the front tires (pretty closely) you can actually watch the front tires dig up the snow or whatever (not very much but enough to notice), or sometimes I can see the rear tires being drug along. I am talking like very slight amounts but still noticeable if you pay attention. Some rigs don't do this and some do, I honestly don't know which ones do this and which ones don't though.

 

Well I guess my 95 DODGE RAM must not be meant for on highway use then. I CAN prove it IS done, can you prove it ISN"T ??

 

Um, it says in your sig "4.56 gears".

 

If I recall, the Dodge W200 was the same way.

 

road tractors are the same way if the truck has a 3.55 gear ratio the front drive is 3.55 and the rear drive axle is a 3.54 and they are designed to drive like that for thousands of miles. it is something to do with the the gear lash and it is actually supposed to make it run freely. a guy (shop foreman) at work was explaining it to me a couple months ago.

 

What brand and model axles did it come with? Let's look up some part numbers and see...

 

jrussel,

Laugh all you want, but I've seen a number of trucks with different ratios too. It seems like it used to be more common than now. Our Dodges are the same front and rear.

In any truck, 4WD or not, the front wheels travel farther on average than the rears. They are always taking a larger arc in turns. Even when going "straight" on the highway you are actually driving an "S" pattern and the fronts are traveling farther than the rears. So a small difference in gearing would actually cause less slip when driving approximately straight in 4WD with a part time system. That is if the fronts were turning slightly faster.

It's a part time system used only where slip is OK and pulling in the front could help the handling by actually compensating for the extra distance travelled by the fronts.

John

 

I've actually heard that too from a couple differant shops, the fronts spin a little faster to pull itself and keep the pickup in a straight line.

 

On road tractors the front drive axle has a "power divider" that directs power to the hub that has the least traction in slick conditions. When the power divider is locked in it puts power to both drive axles (which are open) so that power would go to the drive hub on each axle with the least traction. Under normal road conditions with the power divider unlocked, the power "floats" between the drive hubs just like on an open diff. on a two wheel drive. If you have a difference in ratios or mismatched in size tires on the drive axles it will cause unnessary wear on the power divider. If is is an extreem difference in ratios between axles, it won't last long.