Have a question....

[ChazMan]

For that kind of mudding, you really need to go for manual 4x4 setup.

Another drawback on AWD that I hear is that, because it is viscous coupling at the center transfer case which slips even during normal operation, the temp can get really hot and it can cause problem just like in automatic transmission. Heat kills transmission. But I've never had that kind of heat related issue on my AWD system yet, but it might happen when mudding or serious off-roading when engagment/disengagment constantly happens. The typical 4x4 is all mechanical engagment so there is no such slipping issue or heat problem at the transfercase. This is like auto trans vs manual clutch trans (no fluid).

 

[Arctic-Rodz]

I see... that makes sense

So I guess I should go back to looking into a Z71 Tahoe?

---------- Post added at 01:38 PM ---------- Previous post was at 01:23 PM ----------

Ive also heard that the AWD system has 20% front and 80% power transfer at all times? IF this is so, it wouldnt overheat from activating/deactivating the front wheel by the trans case right?

 

[chip]

Yukon FTW! Just put some 37" Super swampers on some 22"x10" wheels and you're good.

 

[Arctic-Rodz]

id like a yukon to keep my GMC deal goin on

but i cant seem to find many yukons with 4x4... or theyre mostly yukon XL's and well, i dont need a suburban.

 

[bahollis]

Frank, that's a killer pic driving thru the water. I though your truck was tan or grey until I saw the larger shot.

I would shit a brick if I had water up the middle of my doors, and it's 4WD. Mine's more of a city Hoe...

BH

 

[Arctic-Rodz]

Frank, that's a killer pic driving thru the water. I though your truck was tan or grey until I saw the larger shot.

I would shit a brick if I had water up the middle of my doors, and it's 4WD. Mine's more of a city Hoe...

BH

lol thanks, yea that was a lot of fun. Went trail hunting with my brother after we got side swipped by Hurrican Alex a few months back down here in
S. Texas.
Trick was to keep that gas pedal down, cause if you let go, the back pressure sucks the water in and your done. Engine shuts down, but this 98 Yukon can hold its own really well. I was surprised

 

[jhellwig]

There are 2 types of awd transfercases and 1 type of 4x4 in these years mostly.

The bw 4481 is a awd single range case. The power is split through a differential with a 40/60 split in power. The traction control is controlled through the brake system as is the stability system.

The bw 4482 is a awd(the gm service manual called it a full time 4x4 case) dual range case. In high range it is a 40/60 split again through the differential in the case and the traction control and stability control is done with the brakes. In lo range the the case give 2.4:1(Not exact number but close) reduction and the front and rear drive shafts are locked together making a 50/50 split. Traction control and stability control are turned off in lo range. Neutral is also attainable with this case.

There is no viscus clutch in these awd tcases as everyone commonly believes. There is only a planetary differential for the power split.

The clutch(not viscus, electrically actuated) is in the 4x4 transfer case with the auto 4x4. It is an np 246(I think). It is like a normal 4x4 case with 2wd 4x4 and 4 lo. Instead of gears that engage the front drive shaft there is a clutch that is pulled in with a actuator. In auto 4x4 mode the wheel slip in the rear is monitored and the front is engaged incrementally to eliminate slip.

I just read this information out of the 04 gm service manual for these vehicles yesterday and am reciting it from memory. My guess is that most of the years operate like this. I could be wrong. Don't shoot me for it.


The traction control and stability system on these awd vehicles is quite impressive. The traction is controlled through the reading that the abs wheel sensors send and the brakes are applied on individual wheels. The stability is controlled through the abs system also but also incorporates a yaw and lateral acceleration sensor, vehicle speed, brake pressure, steering position and accelerator position to control stability. There is also a prefill pump that takes up the slack in the brake system when an event is anticipated. There is also a prefill pump that primes the system in anticipation of you applying the brakes. That is the noise that is heard from the dash when the system operates or on occasions where it might need to operated. Very impressive system.


Those of you with awd and bigger tires need to reset the yaw rate map for the system to work properly.

 

[chip]

WoW! Impressive post. (and I don't even have AWD).

Thank You!

 

[jhellwig]

I guess I never even answered the original question. I think dinalis had awd. Possible single range.

Awd bites in anything other that mild snow and mud. Traction control and stability works great on the gravel roads.

 

[Arctic-Rodz]

I guess I never even answered the original question. I think dinalis had awd. Possible single range.

Awd bites in anything other that mild snow and mud. Traction control and stability works great on the gravel roads.

hell of a post there bud... so then, for what i wanna use my truck for (towing / off-road) AWD wouldnt do it, correct?