The heart of an offroad vehicle is its drivetrain, but the H3 pamphlet info is pure sales pitch and very light on real technical info.

I'd like to know a lot more about the 4WD system and components. What kind of differential is used for the transfer case? Is it a simple open diff? Whats the difference between the base pkg "electronic locking rear diff", and the offroad pkg "fully locking electronic rear diff". Is there a website with this kind of detail?

The heart of an offroad vehicle is its drivetrain, but the H3 pamphlet info is pure sales pitch and very light on real technical info.

I'd like to know a lot more about the 4WD system and components. What kind of differential is used for the transfer case? Is it a simple open diff? Whats the difference between the base pkg "electronic locking rear diff", and the offroad pkg "fully locking electronic rear diff". Is there a website with this kind of detail?

I think the H3 brochure is pretty good. Did you get the 49 page brochure?

Basically the Jeep Wrangler 4x4 system is less complex than the H3s.

Anyway I hope this helps..I prefer having control of the vehicle rather than a bunch of sensors doing it for me (think Land Rover)...ABS excluded in emergencies etc.

The H3 uses full time 4x4 where the Wrangler is in two wheel drive until the driver engages 4x4 with a lever.

The fulltime 4x4 transfer case allows for use on the highway ("4 High Open")by allowing the front wheels to rotate separately (diff numer of rotations) from the rear wheels where a part-time transfer case the front and rear wheels are mechanically connected and will create bind on the paved highway and on turns.

I beleive you can lock the T-case ("4 High Lock") on the H3 in 4x4 for off road use (this is different than the rear axle locker)

The H3 transfer case is controlled by a switch on the dash (driver controlled) that activates a solinoid to engage low range rather than a lever (all mechanical) in the Jeep Wrangler.

The rear locker on the H3 with the Adventure package is controlled (driver controlled) by a switch on the dash and for use in low range at slow speeds ("4 Low Lock"). The H3 has a rear locker where as a Rubicon Wrangler has a locker in the front and rear axles.

The H3 uses traction control system (part of the (ABS brakes) to control wheel spin and may simulate a front locker..I haven't driven an H3 in this conditions yet....so I can't say for sure. I wish the H3 did offer a Front Locker Option.. Maybe the after market will??

The Rubicon uses a dash mounted switch and the lockers are powered by a low pressure air pump.

I cant wait to get my H3 and give it a work out!

Let me know when you get your H3 !!

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Desert Dan:
I think the H3 brochure is pretty good. Did you get the 49 page brochure? </div></BLOCKQUOTE>

I've got the 49 page orange brochure; its OK for average consumers but the lack of real mechanical specs wouldn't pass muster if they were selling commercially. Doesn't even list gear ratios.

I'm familiar with 4WD systems including Jeep's systems. Since 4WD/AWD systems range from primitive (Jeep TJ) to highly adaptive (Audi/Torsen), I'd like to understand what kind of system I'm buying. I'm not keen on a chip deciding whether I need my rear axle locked or not. Most 4WD mfrs provide a lot more info on how their systems work for mechanical geeks like me.

I'd also like to be sure the Vortec 3500 uses cast iron cylinder liners in the aluminum block. I checked several Vortec engine websites, and none mention it. It should be agiven, but with GM ya just never know!

Here is some good info. including a little about the drivetrain

Combining a five-speed-manual first gear and an optional transfer-case low-range ratio of 4.03:1 (industry leading), the H3 has a crawl ratio of almost 69:1, where most other serious 4x4s are doing well with a 35:1 ratio. The 4.03:1 low-range transfer case is also offered with the four-speed automatic (the 4L60-E), also offering an impressive 56:1 crawl ratio. Further, Hummer engineers had to make suspension changes to allow the H3 wheels to droop and flex over ruts, holes, and rocks with poise and confidence. And although there's no anti-roll bar disconnect, trail flex was impressive for the smallish brute. The H3 will offer 32-inch Bridgestones that performed amazingly well, conforming like marshmallows over the jagged surfaces, once we took out almost 20 pounds of tire pressure.



ENGINE
Type: inline-5, aluminum block and head
Bore x stroke: 3.66 x 4.00 in, 93.0 x 101.6mm
Displacement: 211 cu in, 3451cc
Compression ratio: 10.0:1
Fuel-delivery system: port injection
Valve gear: chain-driven double overhead cams,
4 valves per cylinder, hydraulic lifters,
variable exhaust-valve timing
Power (SAE net): 220 bhp @ 5600 rpm
Torque (SAE net): 225 lb-ft @ 2800 rpm
Redline: 6400 rpm

DRIVETRAIN
Transmission: 4-speed automatic
Final-drive ratio: 4.56:1
4-wheel-drive system: full-time 2-speed with a manual
locking center differential, an open front
differential, and an electronically locking
rear differential; brake-based traction control
Transfer-gear ratios (low/high): 4.03:1/1.00:1
Gear, Ratio, Mph/1000 rpm (L/H), Max test speed (L/H)
I, 3.06, 1.7/6.8, 11/43 mph (6400/6400 rpm)
II, 1.63, 3.2/12.7, 20/81 mph (6400/6400 rpm)
III, 1.00, 5.1/20.8, 33/97 mph (6400/4650 rpm)
IV, 0.70, 7.4/29.6, 47/97 mph (6400/3250 rpm)

DIMENSIONS
Wheelbase: 111.9 in
Track, front/rear: 65.0/65.5 in
Length/width/height: 186.7/74.7/74.5 in
Ground clearance: 9.1 in
Drag area, Cd (0.51) x frontal area (32.9 sq ft): 16.8 sq ft
Curb weight: 4980 lb
Weight distribution, F/R: 50.2/49.8%
Curb weight per horsepower: 22.6 lb
Fuel capacity: 23.0 gal

CHASSIS/BODY
Type: full-length frame
Body material: welded steel stampings

INTERIOR
SAE volume, front seat: 54 cu ft
rear seat: 43 cu ft
cargo, seats up/down: 29/56 cu ft
Front-seat adjustments: fore-and-aft, seatback angle, front height, rear height, lumbar support
Restraint systems, front: manual 3-point belts, driver and passenger front and side airbags
rear: manual 3-point belts

SUSPENSION
Front: ind, unequal-length control arms, torsion bar, anti-roll bar
Rear: rigid axle, leaf springs, anti-roll bar

STEERING
Type: rack-and-pinion with hydraulic power assist
Steering ratio: 17.0:1
Turns lock-to-lock: 3.3
Turning circle curb-to-curb: 37.1 ft

BRAKES
Type: hydraulic with hydraulic power assist and anti-lock control
Front: 12.4 x 1.1-in vented disc
Rear: 12.3 x 0.5-in disc

WHEELS AND TIRES
Wheel size/type: 7.5 x 16 in/cast aluminum
Tires: Bridgestone Dueler A/T RH-S,
LT285/75R-16 116/113Q M+S
Test inflation pressures, F/R: 35/35 psi
Spare: full size on aluminum wheel

C/D TEST RESULTS
ACCELERATION: Seconds
Zero to 30 mph: 3.3
40 mph: 5.0
50 mph: 7.4
60 mph: 10.2
70 mph: 13.5
80 mph: 18.2
90 mph: 26.1
Street start, 5-60 mph: 10.5
Top-gear acceleration, 30-50 mph: 5.2
50-70 mph: 7.2
Standing 1/4-mile: 17.8 sec @ 79 mph
Top speed (governor limited): 97 mph

BRAKING
70-0 mph @ impending lockup: 199 ft

HANDLING
Roadholding, 300-ft-dia skidpad: 0.66 g
Understeer: minimal moderate excessive

FUEL ECONOMY
EPA city driving: 16 mpg
EPA highway driving: 19 mpg
C/D-observed: 15 mpg

INTERIOR SOUND LEVEL
Idle: 45 dBA
Full-throttle acceleration: 77 dBA
70-mph cruising: 69 dBA

The following information may duplicate information already stated by other people. I'm just trying to add more information without having the time to read all the previous messages in total.

In standard four wheel open (normal driving mode) there is 40 percent torque to the front/60 percent torque to the rear.
You can lock the transfer case in HI or LO, and this gives you 50/50 front/rear.
The transfer cases are Borg Warner (BW) models 4493 (standard), or 4494 (off-road).
The front axle has a central disconnect feature. The axle uses a conventional ring and pinion gear set in order to transmit the driving force of the engine to the wheels. The open differential allows the wheels to turn at different rates of speed while the axle continues to transmit the driving force. This prevents tire scuffing when going around corners and premature wear on internal axle parts. The ring and pinion set and the differential are contained within the carrier.
The drive axles are completely flexible assemblies consisting of inner and outer constant velocity CV joints protected by thermoplastic boots and connected by a wheel drive shaft.


The electronic locking rear axle is controlled by the Traction control system. The actual mechanical locking rear axle (fully locking electronic rear differential), available with the off-road suspension package, mechanically locks the rear axles together via a solenoid. However, above 20 mph, the controller will unlock the axles for safety reasons.
Both axles are open differential designs.

Good stuff, guys. Thanks.