GMC Yukon / Yukon Denali

obyone · February 2003

1 pint = 16 ounces = 1/2 quart

obyone · February 2003

Driveline - 4X4/AWD Driveline Characteristics

File In Section: 04 - Driveline Axle

Bulletin No.: 01-04-18-001A

Date: October, 2002

INFORMATION

Subject:
Driveline Characteristics For All-Wheel and Four-Wheel Drive Systems

Models:
2003 and Prior Light Duty Truck Models
with All-Wheel Drive (AWD) or Four-Wheel Drive (4WD)

This bulletin is being revised to update the model years, models and information. Please discard Corporate Bulletin Number 01-04-18-001 (Section 04 - Driveline/Axle).

The purpose of this bulletin is to help explain the operating characteristics of 4WD/AWD systems.

Definitions

AWD vs. 4WD

The very basic difference between AWD and 4WD is the intended usage of the systems.

AWD is usually intended for on-road use in inclement weather conditions, while operating smoothly on dry pavement by allowing for a difference in speed between the front and rear axles while turning. These systems do not have low range gearing for the transfer case.

4WD is intended to be used in low traction or off-road situations. Part time systems do not allow for a difference in speed between the front and rear axles while turning. This system effectively locks the front and rear propeller shafts together. When turning, the tires must slip to allow for the different turning circle of the front and rear axles, which is why this is intended for low traction or off-road use. These systems have low range gearing for the transfer case.

PART-TIME 4WD

Part time 4WD refers to vehicles equipped with a transfer case to split power between the front and rear axles of the vehicle. This traditionally is a 2-speed selectable transfer case that can be shifted into 2H1, 4H1, 4L0 and usually a Neutral position. There is no device to allow for a difference in speed between the front and rear axles. Examples of vehicles with this style of transfer case would be a Silverado with a manual shift transfer case (a shift lever on the floor) (RPO NP2) and a Sonoma with a push button transfer case with a 2H1, 4H1 and 4L0 position (RPO NP1). The RPO codes for this style of transfer case are NP1 (NVG 233, 243, 263) or NP2 (NVG 231, 241, 261, BW 4401, 4470).

FULL-TIME 4WD

A second version of a 4WD transfer case is a full-time 4WD transfer case. This style of transfer case has an open differential to allow for different speeds between the front and rear axles and operates similar to an AWD system. This transfer case can be locked to operate like a 4WD transfer case and or uses a traction control system to assist in low traction situations. An example of this type of 4WD is the H2. RPO code is NR4.

AWD

There are two different categories of AWD Systems. The first category is true AWD. This type of transfer case divides torque to the front and rear axles at all times. This ratio can vary depending on the system, but is usually 30/70% front to rear split but can vary depending on traction conditions, up to 100% front or rear. This type of transfer case can have a viscous coupling along with a planetary gear set to allow for difference in speeds between the front and rear axle or an open type of planetary gear set differential. An example of a vehicle with this type of transfer case is a 2002 Denali. RPO codes for this type of transfer case are NP3 (NVG 149, BW 4473) or NR3 (BW 4481).

The second category is an on-demand AWD. This type of AWD basically delivers torque only to a primary driving axle until a slip event occurs. At that point, the system electronically or mechanically will apply torque to the axle with traction. Depending on the type of system, this can provide up to 100% of the torque to the axle with traction. These transfer cases use an electronically actuated clutch pack, a hydraulically actuated clutch pack, or a viscous coupling to allow for a difference in speed between the front and rear axles. An example of an electronically controlled version of the On-Demand AWD is in the Smart Trak system in the 2002 Bravada. An example of a hydraulically operated On-Demand AWD is the Versa Trak system in the Aztek. The RPO code for the Bravada is NP4 (NVG126). For some vehicle lines, there is not an RPO code. The only way to tell is by the Line Chassis VIN code B or V for the Rendezvous/Aztek, V for the Venture/Montana or by SM for the Vibe.

Automatic Transfer Cases

The last category is a combination of 4WD and On Demand AWD. These transfer cases have a 2H1, AWD, 4H1, 4L0 and Neutral position and would fall in the general 4WD category. This transfer case has the operating characteristics of both an On Demand AWD and a 4WD system depending on the mode selected. This transfer case uses a clutch pack to allow for a difference in speed between the front and rear axles in the AWD mode. In the 4H1 or 4L0 modes, there is no allowance for the difference in speed between the front and rear axles. An example of a vehicle with this would be a Sierra with a push-button transfer case with a 2H1, AWD, 4H1, 4L0, and Neutral positions. The RPO code for these transfer cases is NP8 (NVG 236, 246).

Characteristics

4WD

A part time or automatic 4WD transfer case will make - more noise while operated in 4H1 and in 4L0 (a full time 4WD will operate similarly in 4H1 lock or 4L0 lock). This noise can vary depending on the transfer case type, GVW ratings (generally the higher the GVW the more noise it will make), vehicle build variations, gear ratios in the axles, axle type, tires, and importantly driving conditions. This type of system's intended use is on loose traction surfaces such as a dirt road, mud or snow. If this system is used on hard packed surfaces such as dry pavement, driveline binding will occur because there is no device to allow for the different speeds between the front and rear axles. This will cause noise in the axles, transfer case and the rest of the driveline, and will usually increase the more the vehicle is turned. As the vehicle turns, the front and rear axles follow a different arc. When this happens, the only way to compensate is for the tires to slip, which will feel like the vehicle is crow hopping or grabbing. Even if the vehicle is driven in a straight line, there are slight differences in tire circumference that will cause some driveline binding. If a vehicle had the exact same size tires and was driven in a perfectly straight line, the fact that more parts are moving would mean that there will be more noise.

When driving in 4L0, the extra gear reduction will make additional noise compared to driving in 4H1.

While the transfer case is in Neutral, with the engine running, some noise can be expected. When the transfer case is shifted from neutral with the engine running, some gear clash can be expected.

AWD

AWD systems are designed to be used in high and low traction situations. These systems will generally be quieter on high traction surfaces than a similar 4WD used in 4H1 or 4L0. However, these systems will make m

dxl1 · February 2003

Could be a TSB on it, but they really seem to be having an issue with the front diff. I had mine replaced (about 12,000 miles) and the whining went away. It was making me nuts ... of course my ex-girlfriends would argue with the "making" part of that.

dxl1 · February 2003

I get a pulsation kind of like sitting by a sub-woofer @ 30-45 MPH. Dealer said they called tech support and that was a normal occurance. Anyone else have experience with this issue?

jboater · February 2003

I bought a pre-owned 02 YD two weeks ago, 14k miles on it. I've run 2 tanks of reg fuel and am averaging 12.5 mpg on roughly a 50/50 mix of city and x-way driving. This is in line with the expectations I had but seems to be noticeably lower than some other posts here. Are these other posts exceptions to the norm or is there something I can do to enhance my mpg?

dxl1 · February 2003

Sounds like you are running a little low on the MPG. Mine does around 13.5 with city/hwy driving.

obyone · February 2003

I'm getting 12.9 combined 70/30 highway/city since day one.

orwoody · February 2003

Well, after 34k miles and almost two years I'm experiencing my first nuisance issue with my 2001 Denali. The front passenger speaker on the door has developed a metallic resonance/buzz at certain AM frequencies.(I listen to the news and road report on my commute.) It's not constant but I want to remove the speaker cover and check it out. Does anyone know if the cover just pops off or ?
I don't want to screw it up trying to remove it.

ahesq · February 2003

Guess this is why I was an English major. The amount of gear oil I added to the front diff was a little over a quart, (not pint as mentioned earlier). It's a good thing we didn't get into liters!!

In any event, I have appt. with dealer to flush and refill front diff. We'll see how that works.

Don't see a TSB on this (yet)

cornellpinoy · February 2003

Hi, everyone. Just thought I'd share my experiences with my 2002 Denali (now with 12K miles):

Transmission was slipping @ 4000 miles and was replaced.

High frequency buzz from speakers that got louder as the rpms increased due to a bad wiring harness.

Rear vibration/buzz @ 40mph due to a bad exhaust heat shield.

Leak from front differential due to loose connector.

Condensation in 3rd brake light.

Wrong emissions decal on engine with 5.3L info instead of 6.0L info.

It was disappointing to find these problems and other damage caused by the dealer while it was with them during repairs. Also disappointing that the dealership doesn't provide the level of service expected when one buys a $50K vehicle.

However, I still believe this a lot of truck for the money and that its a better buy than the other luxury SUVs on the market.

I appreciate reading all your problems/solutions and will continue to share any problems/solutions I experience.

Oh, has anyone had any problems with their power steering? I'm beginning to hear noises when I turn the wheel while parking.

Thanks!

swellmels · February 2003

I am new to the posting, but want to let you know when we were looking at buying a new suv these postings where a huge help in making Denali our choice. Only the best! Any way the reason for my post is we are heading up to the snow which in California takes about 4 hours and need to have cables with us due to state law. Can anyone please let me know what the best choice is. The manual says none, and other posts never really answer the questions. Help

erinsquared · February 2003

I really enjoyed the information about the driveline you provided in message 1768. Is there any possibility you could provide the link to that information?

jboater · February 2003

dxl1 and obyone, thanks for the feedback.

trklvr · February 2003

Any feelings on the quadrasteer being an asset or a liability at resale time? I'm thinking it would be nice to have, although I don't really NEED it, but I haven't heard much about whether it's holding up well. I really love my '00 SLT, but w/ 27K it needed a warranty engine (and more little fixes than I think it should have had) and now the 3 yr/36K is done....I'm done with the headaches and want a 2003 SLT; I just can't decide on the quadrasteer. I would like feedback, thanks,

dailydouble · February 2003

anyone have a vibrating side mirror? My drivers side vibrates VERY slightly at around 50MPH... the passenger side one is ROCK solid... it is annoying...the dealer has replaced it twice. the first time it was much better but still vibrated, the second time no difference . My service manger tried to tell me it was "normal and the best they could do"...I asked why the passenger one was so solid...no answer.....
I also have a vibration from the rear left compartment where the jack is located..they "found it" took it apart, and "insulated" the rear air unit....ok for 2 days and vibrates again when going over bumpy roads slowly..it is more annoying than anything and my confidence in the dealer is gong downhill fast..

jkpsaras · February 2003

Is the noise in the steering column/wheel, or the front end. I had a noise in the steering column, a rubbing cable. Dealer fixed this on their first try!

orwoody · February 2003

My driver's mirror sometimes vibrates ever so little on certain types/roughness of pavement. Not nearly as bad as the older style GM mirrors I've had on previous Sierra PUs. It hasn't been irritating enough or continuous that I sought a fix.

Hey anybody out there in the NE care to comment on how the Denali/DXL does in the deep snow you've been getting? I'm headed to Boston on business(no not driving) and got curious.

Last tank of petrol I got 15.4 calcualted (15.2 on DTC) running about 70%/30% freeway/city.

obyone · February 2003

Sorry I can't provide a link as the site's password protected. There is a similar one available for a fee. If you do decide to sign up for it, select the 2001 model year as its more comprehensive.

http://www.alldatadiy.com

cornellpinoy · February 2003

Daily double: the driver side mirror on my 02 Denali also vibrates at speed. I thought it was due to the smaller wide-angle stick-on mirror I attached to it. I've driven numerous Trailblazers/Envoys and Tahoes/Yukons. Some have the same vibration, some don't.

jkpsaras: Thanks for the feedback regarding your steering noise. I'll definitely have mine looked at the next time I'm at the dealer.

dailydouble · February 2003

When I got mine in June 2002...it was getting a whopping 11 MPG....steadily, it has moved up and now I average 14.2 according to the computer....on a 900 mile mainly interstate trip I got 15.

csi35 · February 2003

Yesterday was the first opportunity to see how my 02 Denali would operate in 24 + inches of snow.

After 2 minutes of warmup I put vehicle in gear and gave it very little gas (no more than 1000 rpm) and plowed thru the 24" on my driveway and thru the 35" mound that the snow plow kindly left at the end of my driveway. Like a hot knife thru butter.

Got on the main highway and saw nothing but SUVs. I wonder what those people who post here saying they hate SUVs and are trapped at home with their Yugos and such think now. Hope they didn't have an emergency and couldn't get out of their driveway.

Some cities/towns wouldn't let you drive unless you either had chains on or had a 4 wheel drive.

This vehicle is worth every penny I paid.

thedeans · February 2003

The 2001 Denali that I am considering purchasing has the bucket leather seats in the second row. Does anyone have any experience with using an infant car seat in these seats?

stacy · February 2003

I have 02 Denali. One Graco infant seat in one chair. One Britax (read that enormous) Roundabout in the other. One large 6 year old in the back seat (read that easy access to the third row via the opening in the middle of the car and a feeling by my child that he is not all alone back there, he did not like the bench nor did I) I would not want to put infant seat in the middle of a bench because it is too dangerous to maneuver the baby across that much space balancing on the step. The infant seats, toddler seat and booster seat all work well in the captains chairs. Plus they recline when your kids get older and are out of their seats and want to rest or sleep. For me, capt chairs were a no brainer. Hope this helps. (P.S. No latch on mine - still very tight and secure. My DXL is the safest car on the road IMO.)

avolvofan · February 2003

If the noise is a faint rumbling sensation (mostly felt rather than heard) while driving over bumps, it could be in the steering column bearings. My 2001 Denali recently developed the rumbling and was fixed by the dealer under warranty. The repair involves re-packing the steering column bearings.

jammon1 · February 2003

I have an 01 Denali XL with the 2nd row bucket seats. I put child seats in both 2nd row buckets most of the time. They work great. I use the new LATCH child seats but hook them to the steel seat frame that is accessable between the bottom and the back of the seats. They tighten down rock solid.

dailydouble · February 2003

How do you retain the child seat at the top?
I have an 02 Denali and only see the latch mechanism on the bottom...

jammon1 · February 2003

The back strap goes over the back of the seat (under the headrest). There is a place to clip the back strap to the base of the seat. Check the owners manual for the Denali, it will show a diagram of the latch points. Using the latch strap on each side and the back strap the child seat becomes rock solid. When you pull the side strap down, put a knee in the child seat to push it down tight.

dailydouble · February 2003

Thank you, I will look.
At the moment I have no need to use the child seat, but hopefully in the next year or so I will!

peterfromswede · February 2003

Hello my name is Peter, from stockholm sweden.
Here it´s very hard to find a 00-03 Yukon XL or Suburban. And the few that have been imported are redicoulusly expensive. So i might as well do all the work by myself (instead of letting a dealer make a fortune on me.)
My question is: I need help to find a searchengine where i can search for cars on the eastcoast in the US. I´ve been looking a bit at www.autotrader.com but i would appriaciate if any of you guys could recommend another one.
I have a contact in New Jersey that will take care of the shipping and so on, therefor i would like to find one in that aera.
The car i´m looking for is a Yukon XL Denali, say 2002-2004. Or should i go for just a Yukon XL or Suburban? What is really the differens exept for the exteriör?

Thanks

Peter, stockholm

stever · February 2003

You can try our Vehicle Locator Link link (keep playing with the zipcodes for different areas).

Steve, Host

lobsenza · February 2003

hhas all wheel drive, larger engine, heavier duty trans, trans temp guage, additional cooling, 17" wheels and tires, upgraded interior, and exterior trim changes. It also has a Bose sound system which is optional on the YXL and Suburban for 03. 03 has cosmetic differences as well and an optional DVD entertainment system. Stability control is also available for 03. 03s have a middle row shoulder belt and the earlier models do not. There are also some cosmetic items deleted from the 03s that the earlier models had....

dailydouble · February 2003

I qualified for the supplier price and calculated I was getting around 9% discount on the Yukon and 13% on the Denali.....after I took this off the list prices, the Denali was only a 'few' grand more....when I looked at the standard yukon next to the Denali version...there was no second opinion required....DENALI all the way!....
The interior on the Denali is FAR better than standard Yukon.
But, it is my intention to keep this for a good 5-7 years and the extra money has been "well spent".
It is going to cost a lot of money to ship it to Sweden ??
Web sites...new???
www.gmbuypower.com

denali856 · February 2003

I had good luck working with autobytel.com.

shorty12 · February 2003

I saw earlier post in which it is noted that the driver had no problem with 24" of snow. However, my question regards how well AWD works in relation to 4X4 (we are planning on purchasing soon). We have a Nissan Pathfinder with All-Mode 4WD which according to Nissan works as follows:

Set the dash-mounted switch to AUTO and the system takes over, automatically and instantaneously adjusting the front-to-rear torque according to the changing traction. So you get optimal 2WD fuel economy when the going's easy, and optimal 4WD traction when it's not. The AUTO-mode torque control is also linked to the all-terrain ABS, enhancing braking effectiveness and vehicle stability when ABS is applied.

Having said all this we were less than impressed with AUTO-mode and ended up manually switching the system to fulltime 4X4 for our drive through the ice and snow of West Virginia.

We just don't want to end up with a truck that isn't able to handle snow and ice conditions as well as a 4X4.

Any feedback will be greatly appreciated!

shorty12 · February 2003

Peter,

You also may want to try:

www.cars.com
www.gmc.com

Cars.com has options to search for both new and used cars (the majority of the used vehicles listed are actually at dealerships).

GMC.com will allow you to build the vehicle you want. Then you can press a button to have the web page for a dealership that has a vehicle similar to the one you built.

If you need zip codes associated with East coast cities in order to perform your search you can locate them at www.usps.com

Good luck!

lobsenza · February 2003

Auto $WD has a lag for the slipping tp be detected and to switch into 4WD. AWD is always in 4WD, so you don't have that slipping. The GM AWD vehicles do not have a 4 lo, so they are not as good for heavy duty off road driving. AWD does very well on slick streets. I personally would prefer AWD if your use is primarily street use...

scottinssmd · February 2003

I've taken 'Danny the Denali' on many trips to Wisp and Snowshoe this year. I've noticed the hood bouncing as if it were unlatched. Almost a distraction. When I physically try to lift, its tight. No give. Yes, I do have a air deflector on the front. My guess is, the air would keep it pinned down at best. Is this just the way it has to be? I'm not looking to mess with the latch, but if someone else has noticed and remedied, please respond.

Thanks.

jboater · February 2003

At the direction of my DIC, I recently changed oil (now using Mobil 1 syn 10/30). I also added fuel injection cleaner to the fuel. Last tank of fuel showed an increase in MPG from 12.6 to 13.5. I've also found that the DIC computes MPG 0.2 higher than my manual computation. I'll be interested to so if the improvement remains on the current and future tanks of fuel.

jkpsaras · February 2003

I switched to Mobile 1 on my 2001. I noticed the same improvement in mileage. I switched at around 10K miles.

jgmilberg · February 2003

Check the hood bumpers on each corner. If those are not contacting the underside of the hood it will wobble around and look loose.

yukonxldnyc · March 2003

Just picked it up on Monday. Never owned a GMC Yukon XL (or Chev Suburban) before. Traded in my '99 MB ML430, which was an excellent SUV, but I needed more room for kids.

Options: 2nd row captains' chairs (AL4), sunroof (CF5), multimedia sound system w/navigation system (UM8).

The factory nav system (included in the multimedia sound system UM8) is a MUST have, in my opinion. It is excellent. I had the factory nav system in the ML430 too. This is an option that I couldn't live without, and I waited until I could get it before placing my GMC order in January (it wasn't available until that time). I never had Onstar before, but I consider it to be a completely different safety and emergency system -- an adjunct to the on-board nav system.

The truck was built and delivered in about 7 weeks. Nobody at the dealership had ever seen the nav system before!

Price, including options and destination charge, was $48,675 (before $2,500 rebate). After rebate, price was $46,175. This seems to be about $124 less than the invoice less dealer holdback (3% of MSRP before dest. chg.). I shopped a number of dealers before finding this price.

So far, the truck seems fine, although there are some annoying noises in the instrument panel. Also, the accelerator pedal seems a bit flaccid (should have more resistance like the ML430). The 6 liter engine seems fine.

If anyone has had any recent problems with their 2003 Yukon XL's, I'd appreciate knowing.

black_debt · March 2003

All,
I want to replace the red "GMC" grill emblem with a chrome one. I know they're out there because I've seen them on other trucks. Anyone know where to get it and also how to take the old one off? Thanks in advance.

B.D.

jammon1 · March 2003

It is pretty easy to change out. stylinconcepts.com sells one made by Trenz and another company. Both come in either brushed or polished aluminum. They are individual letters; "G" "M" "C". So you have to line them up when you install them. They simply stick on the stock grill once you remove the original red "GMC". To remove the red "GMC" you will need to remove the fan cover under the hood. There are 8 or so plastic clips that you pull the center up and then the who clip comes out. Once you have that plastic fan cover removed you can reach behind the grill and simply unclip the red "GMC". Then put the fan cover back on, clean the grill where the new GMC letters will go and stick them on. Start with the "M" and then put the "G" and "C" on. That will keep things centered and evenly spaced. Good Luck!

obyone · March 2003

I know adhesives have come a long way...but is it enough to secure the GMC logo? Sounds kinda cheesy to me. I was thinking of changing out the entire grill to get rid of the logos completely. Just haven't found a replacement grill which is similar to the stock one.

jammon1 · March 2003

I agree about adhesives. The letters look very nice. Polished aluminum with edge detail. They come with the adhesive already on the letters. You clean the grill with some alcohol wipes that they supply and stick them on. I have had them on for about 10 months now. Through many washes, rough roads, freezing cold weather and so far they are holding great. My next step would be to replace the whole grill with a non-logo aluminum type.

stacy · March 2003

Polished aluminum logo purchased through manufacturer empiremotorsports.com. You can get it polished (what I got)or brushed. The letters are exactly like the red logo. They are all together. Not stick on but screwed in. You have to remove the grill - somehow. I opened the hood and decided to get someone else to do it. My dealer did it for free but I was quoted 30$ from a chop shop. The grill looks great. The dealer is going to order some to keep in stock there at their parts counter. Personally, I would not want individual letters as they might adhere crooked and then the point of having the grill look better will be gone. Good luck.

jammon1 · March 2003

I would go for the single "GMC" unit with the screws as well. I did not find that when I searched 10 months ago.

black_debt · March 2003

Thanks for all the input. I'll check out EmpireMotorSports.com. Sounds like exactly what I was looking for.

snowdon · March 2003

MSRP for $52,545 selling it for $47,000 plus fees before $3000 rebates?

What is your thoughts?

snowdon1 · March 2003

I can not decide if the 6K is worth it for the Denali XL, we live in Southern California so the AWD is worthless, any advice?

GMC Yukon / Yukon Denali

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