Is a 4x4 transfer case essentially a gearbox?

[sanpt7777]

So, I am sure a transfer case is a gearbox in a dumbed down way of explaining it. The reason I ask is I have been sure before, only to learn I was wrong.

So, to the engineers and knowledgeable GCF members, is a transfer case essentially another gearbox?

I once also explained to my good friend and his cousin that his (my friend's) old 4x4 Vitara had essentially 10 speeds because you have Low and High gearing, so 5 low speeds plus 5 high speeds means you have 10 gear ratios to chose from, right? This came up when I told them the Vitara would have been just fine pulling my Volvo when it broke down (we ended using a Chevy pickup) because it had short gearing even in High setting, even if the engine is not too powerful.

They laughed at me, obviously. I was laughed at too when I told them different gear ratios were used in cars to multiply engine torque at the expense of speed. Hence, if driven slow, the Vitara could easily pull the Volvo on a flat road because it's small engine's torque is multiplied. They still couldn't believe me, and they are engineering students (Mechanical and my friend is a brilliant student in mechatronics)

Prove me wrong please, if I am, or just tell me I was right so I can use this example again with someone who is asking. I don't want to share missinformation.

Cheers!


PS I don't meant to say it's OK to tow a car with the transfer case set to Low, I'd pull it in 2wd High. I don't think it's safe to use 4x4 low to tow a car, but maybe it's OK for 100 meters or so if the road is uphill and extra torque is required?

 

[Giannis]

A transfer case is exactly that, a transfer case.

It's got a set of gears and/ or chains used to transfer torque from the gearbox to the front and rear axle. There can also be an extra torque multiplication mechanism that can be engaged at will - the low gears. You will find a distinct transfer case in cars with a mechanically activated AWD system, cars like the Suzuki Jimney, where you use a lever to choose between 2WD or 4WD and engage the low gears.

I once also explained to my good friend and his cousin that his (my friend's) old 4x4 Vitara had essentially 10 speeds because you have Low and High gearing, so 5 low speeds plus 5 high speeds means you have 10 gear ratios to chose from, right?

Your friend's Vitara has 5 speeds. It's gearbox has five speeds. It also has a low gearing mechanism, that uses the very same 5 speeds.

You will find something similar in commercial trucks' gearboxes. There you select in sequential function 1st low, then 1st high, then 2nd low, then 2nd high, etc, but it's a semi-automatic type of gearbox, where you manually operate the clutch and with a lever you select the gear. It goes forwards and backwards to go up and down a gear, and you also have a button that engages the low gears. This system also has 5 gears, but the way the low gearing mechanism is integrated to the system, make the 5 gears 10.

In your friend's Vitara you can't go from 1H to 2L. You can either use the HIGH or LOW pattern. You can't shift from a high gear into a low one.

This came up when I told them the Vitara would have been just fine pulling my Volvo when it broke down (we ended using a Chevy pickup) because it had short gearing even in High setting, even if the engine is not too powerful.

It would have done just fine, even without engaging the low gears. I've pulled mine from mud with a 1993 VW Polo 1.0l (~50hp). I have also used a 1986 Suzuki Samurai 1.0 (~55hp) to pull a 2.5tons double axle generator up to speeds of 80 km/h. In retrospect I wouldn't do any of those two things again, but they certainly are doable.

 

[sanpt7777]

A transfer case is exactly that, a transfer case.

Yep I know, I'm just talking 4x4 and over simplifying things by saying it works like a 2 speed gearbox, I know it's not correct but I thought at the moment it was an easier way of explaining things.

In your friend's Vitara you can't go from 1H to 2L. You can either use the HIGH or LOW pattern. You can't shift from a high gear into a low one.

I am aware I can't go from 1st low to 1st high and then 2nd low to 2nd high and so on, I just meant that you effectively have 10 gear ratios to choose from, right?

1st low
2nd low
3rd low
4th low
5th low
1st high
2nd high
3rd high
4th high
5th high

It would have done just fine, even without engaging the low gears. I've pulled mine from mud with a 1993 VW Polo 1.0l (~50hp). I have also used a 1986 Suzuki Samurai 1.0 (~55hp) to pull a 2.5tons double axle generator up to speeds of 80 km/h. In retrospect I wouldn't do any of those two things again, but they certainly are doable.

Lol. That's exactly what I told him and his dad, but his dad told me to take his pickup because it had more torque, and I proceeded to destroy his rear bumper with the steel wire rope I wrapped around it since it didn't had any kind of tow hook unlike the Vitara and the Volvo. The tow hook was the reason I wanted to take the Vitara.

Thanks man.