Which 4WD Mode and when.....?

[H2mike]

I have not had the chance/time to do much off-roading. Just wondering if everyone could post their experiences with terrain along with the mode you use. What conditions do you use 4-HI / 4-LO / Diff lock etc. Also, please post your expeiences with snow!!

Thanks!

[H2mike]

I have not had the chance/time to do much off-roading. Just wondering if everyone could post their experiences with terrain along with the mode you use. What conditions do you use 4-HI / 4-LO / Diff lock etc. Also, please post your expeiences with snow!!

Thanks!

[Centerfire]

Yep.. me too. I read the manual.. its a bit vague... If some of you H2 Vets coiuld pass on some words of wisdom it would be apreciated. ALso snow is my primary concern this winter.. AS my daughter asked to use my Sub this winter so she and the new granddaughter don't get stuck.
The more I read the manual the stupider I seemed to get.

Mike

[H2Doc]

I would also appreciate any advice on 4WD modes, tire pressures and basic offroading techniques by experienced Hummer owners.

Brian

[Buckeye Hummer]

Pavement=4HI
Smooth Dirt Road=4HI
Rugged Terrain (loose dirt, sand, deep ruts, inclines, declines, rocks, boulders)=4LO in gears 1-3
Severe Terrain (above with major obstacles)=4LO, rear diff. locked gears 1-2
Mud, Snow=depends whether the trail is smooth or has obstacles under this mess. Play with it a bit to look for best traction and control.
Tire Pressure=20 works ok for most rugged terrain.

Others can chime in with more mud experience. It's awful dry here in L.A.

Also, Hummers are made for torque. Watch your RPMs. They should not get too high for max torque over obstacles and rugged terrain. If you hear the engine winding up you're probably in the wrong gear or setting for the terrain you are in meaning 4LO in gear 2 for dirt road at a good clip just ain't right!

[DURAMAX TIM]

Mud is great, some kind of mud tire is a great help too.
I run 4 low lock w/ rear locker engaged (note above 25 mph the rear locker will disengage so after a blast thru the mud u have to lock it back in).
Muddy hill climb I had the TC in normal and the brakes kept pulling the motor down, so the others I told to use TC2 for more tire slip before TC starts braking.
Drive it like u stole it helps too, the big chunks of mud will wash off the top of the roof

Yell'r 04 Lux w/ air, sunroof,F&R brush bars
Traded 03 White Lux
03 GMC D/A CC SLT LB soon to be 04

[Centerfire]

OK Ok Ok.. I got the mud part. Thanks for info.. ?? What is the advantage if any running thru snow ( on pavement) to changing to 4Hi/ 4 Lo extra..
Don't really go off road.Howevve I think my red H2 has about the same amount of mud and a lot more grss on the side on it right now. Crossing grass interstate dividers can be a bear in the rain. Although it was much easier then using a Crown Vic,

Mike

[unaslob]

you have to drop to 4 high locked in mild to moderate snow.. if you are kind enough to pull people out of the snow.. I suggest dropping to 4 low. I would echo and even stress the importance of RPM control.. the key is bringing up those rpms very slowly in looser conditions.. it is really easy to get on the gas and spin them... let us remember that the coefficient of static friction is much greater then the coefficient of kinetic friction.

una!!!

"Arrh... the laws of physics be a harsh mistress" - Bender

(obscure quote)

[Centerfire]

Again thanks for the info. Why do you have to drop into 4 HI lock as opposed to the normal way it runs? What is the difference in operation between the two.

Mike

[unaslob]

well right now in the reg 4H.. you are "all wheel drive" which divides the power to about 70% rear and 30% front, it is supposed to vary..... the 4H lock splits it to 50/50 considering most of the weight of the truck is in the front this is much better...the traction control out performs and allwheel drive system anyway. if the conditions are slippery but you are in safe area and want to have fun, then leave it in reg 4H... and have some fun slipping and sliding around..

One of the best things you can do to get to know your truck is to find a nice parking lot late at night with some snow all over... and test out the different configurations.. it will be a learning experience... it takes some getting used to having the traction control activate itself, something worth feeling happen on your own terms... una!!

[Centerfire]

Thanks for basic tech info.. I have pleanty of snow experience in both 2wd and 4wd. However I always take a new 4wd out in the open during the 1st snow to test its limits. then the same chekcing it out in heavy drifts.Which is usualy my 900ft drive way. Every other winter we get 4 " drifts down the driveway. My 99 Sub has auto 4wd. It is an odd felling when it kicks in and out. will be interesting how the H2 will fell going form 30/70 to 50/50.

THanks again, I will reread the manual for explaination of when and how toshift into different ranges.

Mike

[SRFCASTR]

Any comments on SAND?

Deep Soft Sand

Hard Packed Sand

Either on Incline

Wet Soft Sand

Thanx

SRFCASTR