[The_Warlin]

I am a bit confused on the Trailhawk 4x4 system. I thought that the Sport/Latitude/Limited 4x4 systems were basically where you choose to turn on 4x4/in auto mode were basically 4x2 on the interstate. I also thought the Trailhawk was "full time 4x4" as in AWD, but is it really just the same as the other models? Why the less MPG?

 

[CalTom]

I am a bit confused on the Trailhawk 4x4 system. I thought that the Sport/Latitude/Limited 4x4 systems were basically where you choose to turn on 4x4/in auto mode were basically 4x2 on the interstate. I also thought the Trailhawk was "full time 4x4" as in AWD, but is it really just the same as the other models? Why the less MPG?

Yes, except for Rock mode and 300-400 pounds extra weight, skid plates, etc. Also the .8 inch lift and different profile front bumper increases drag reducing mpg.

 

[bwbike]

The Trailhawk 4x4 system does indeed work the same as the other trim level automatic cars. But the final drive gear is 4.334 (as compared to 3.734) so the engine RPM will be slightly higher than the others. This will use slightly more fuel than the other automatic models. Most probably won't notice a difference.

The 1.4T manual 4x4 also has the 4.334 final drive gear but has a different transmission.

The rock mode on the Trailhawk is really a software mode. What it does is to hold the transmission in first gear. That and the 4.334 provide the 20:1 crawl ratio. That is likely all most will need with this car.

Of course, it can't compare to a real 4x4 low system with a two-speed transfer case. These systems provide crawl ratios around 40:1 in low gear.

 

[Indiana Jones]

The rear axle locks too..... Or something like that. The 4WD system in the Trailhawk is different than the standard 4X4. The TH doesn't gain 300Lbs over just a great ratio change.

 

[Slawek]

Trailhawk gains 179lbs

Base Curb Weight
1.4L 4x2 3,025
1.4L 4x4 3,190
2.4L 4x2 3,126
2.4L 4x4 3,311
2.4L 4x4 Trailhawk® 3,490

source https://www.jeep.com/assets/pdf/renegade_spec.pdf

 

[bwbike]

The rear axle locks too..... Or something like that. . . .

I've read that somewhere that the rear axle locks. I assume that means it works like a limited slip differential. However, I have not been able to verify that anywhere except on the Cherokee (or Grand Cherokee).

But the rear axle lock might mean that the drive shaft to the rear axle locks to the transmission so there is no slippage.

In either case, the computer likely uses the brakes to "hold" any wheel that loses traction or comes up off the ground.

 

[artyup]

Skid plates and tow hooks, heavier tires and along with the locker add the # although the locker shouldn't add much.

 

[raz-0]

The only difference in the 4x4 for the TH is final drive ratio, and the addition via software and a button change to have a "rock" mode that not only locks AWD mode on, but restricts it to first gear to get the 20:1 crawl ratio.

They all disconnect the drive shaft and become essentially FWD cars under normal driving unless there is some sort of wheel slip. From all descriptions, it seems it is an open diff up front and in the rear and the ABS system is used to limit slip. The center diff is a multi-plate wet clutch system.

 

[NBCGLX]

The only difference in the 4x4 for the TH is final drive ratio, and the addition via software and a button change to have a "rock" mode that not only locks AWD mode on, but restricts it to first gear to get the 20:1 crawl ratio.

They all disconnect the drive shaft and become essentially FWD cars under normal driving unless there is some sort of wheel slip. From all descriptions, it seems it is an open diff up front and in the rear and the ABS system is used to limit slip. The center diff is a multi-plate wet clutch system.

Spot on. The only mechanical difference between the TH and other 4x4 models is the transmission final drive. Everything else is software driven.

 

[bwbike]

4x4 Updtate

It turns out that you aren't restricted to 1st gear while in rock mode. It will shift to at least third gear and/or you hit 25 mph then rock mode turns off.

The throttle input is way different too. You need to press the gas much further than you normally would. I'm sure this is so you can modulate the throttle more easily.

 

[raz-0]

It turns out that you aren't restricted to 1st gear while in rock mode. It will shift to at least third gear and/or you hit 25 mph then rock mode turns off.

The throttle input is way different too. You need to press the gas much further than you normally would. I'm sure this is so you can modulate the throttle more easily.

Interesting info.

 

[Nick1236]

Bringing back an old thread,

I have searched this site several times now, does the TH have lockers or is it all software? I cant seem to find a real answer to this.

 

[Copperhead]

Bringing back an old thread,

I have searched this site several times now, does the TH have lockers or is it all software? I cant seem to find a real answer to this.

It does not have lockers. It has "Brake Lock Traction Control" which uses brakes to create a locker like effect when crawling.

 

[MRM331]

Do all 4x4 Renegades have this brake lock system or just the TH? I had my Latitude in some pretty serious mud bogs and it seemed as though the rear wheels were shuffling torque back and forth.

-Jason

 

[dontpanic13]

Do all 4x4 Renegades have this brake lock system or just the TH? I had my Latitude in some pretty serious mud bogs and it seemed as though the rear wheels were shuffling torque back and forth.

-Jason

According to the Jeep website this should be available on all models. They even have a little video going over how the different modes operate.

http://www.jeep.com/en/4x4/index.html#ActiveDrive1*

 

[MRM331]

According to the Jeep website this should be available on all models. They even have a little video going over how the different modes operate.

http://www.jeep.com/en/4x4/index.html#ActiveDrive1*

So basically then if you just don't shift your 6-speed Renegade out of 1st gear and let it crawl along at 5 or so mph (which it can do) while in 4WD mode you have essentially recreated "Rock Mode"?

-Jason

 

[JimV]

So basically then if you just don't shift your 6-speed Renegade out of 1st gear and let it crawl along at 5 or so mph (which it can do) while in 4WD mode you have essentially recreated "Rock Mode"?

-Jason

Not really. In first you have what I used to call a "Bull Gear". Really low and good for almost all terrain. But Rock Mode adds a 20:1 reduction onto that. so your first gear is more like fourth (maybe, that's a total guess). You cannot get that low a gear without "Rock Mode".

 

[JimV]

Not really. So your first gear is more like fourth (maybe, that's a total guess). You cannot get that low a gear without "Rock Mode".

That came out wrong... A six speed first gear may appear as fourth gear IF you were in Rock Mode, because of the gear reduction....

 

[raz-0]

So basically then if you just don't shift your 6-speed Renegade out of 1st gear and let it crawl along at 5 or so mph (which it can do) while in 4WD mode you have essentially recreated "Rock Mode"?

-Jason

If the final drive ratio were the same, then yes you would have recreated 90% of it. Jeep claims it also affects torque distribution left/right for the rear wheels.

But final drive ratio is different, so doing that in other models gets you something like 17:1 and TH gets you 20:1.

 

[MRM331]

In first gear a 1.4t has an 18:1 final drive ratio. The engine also has greater lower end torque than the non-turbo which means it can handle crawling around at at lower rpms than the other. I was surprised to discover exactly how slow I can crawl in first gear without feathering the clutch. With the clutch totally engaged (foot off the pedal) I can maintain a steady 5 to 7 mph without any hint of bucking or lugging.

When in rock mode how slow can a TH go before it stalls? Its got to be like 3 mph or something, right?

-Jason