Hi Austin,

I need your advise on something. I had recently purchased a GMC Yukon SLT 2004 Model. The car has been imported from USA and it has 88k miles on it. I dont know the maintenence history of this car and I had no experience on GMC trucks before, hence can you please guide me what
things (which oils, (engine/transmission/differential/transfer case), filters etc.) shall I check and change in this vehicle to start a fresh
history for the car. Also, can I use Mobil 1 synthetic oil in this engine.

Your important advice will help me and acting upon your advise will give me peace of mind. Also I will appreciate your early response as I want to do all the checks and changes as you will advise before I start driving this car.

Best Regards

Rashid

Hey there Rashid,

Have you seen my 80,000 mile auto maintenance schedules yet? Here is one closest to your mileage.

Since you do not know the maintenance history of this vehicle, I would service the transmission fluid and filter, flush and fill the cooling system, change the differential and transfer case oils, and install a new fuel filter and spark plugs….and if this engine has the old fashioned spark plug wires, I would replace them as well with the new spark plugs.

I would also remove the wheels and inspect the brakes, and rotate and balance the tires while I had them off the vehicle. SUV tires wear differently than smaller car tires, so you will want to keep them rotated and balanced more often….like every 10,000 miles.

Yes you can use Mobile 1, that is good oil and will be perfect for this vehicle.

This is a great vehicle….fun to drive, easy to work on and dependable….just not very good on fuel mileage.

Blessings,

Austin Davis

We have a 2000 GMC Savana full size conversion van. We had a small transmission fluid leak at the main seal for quite some time, but always checked the fluid levels and added ATF when needed. About 3 months ago, we took it to a local mechanic and had this main seal replaced. When I picked the van up, it would not move in reverse.

The mechanic finally got it to back up, and said that it may take some time for the pressure to build back up, and to drive it for a few days to make sure (it went forward with little problems). By the time I got home, it would back up fine, and we have noticed that the leak is fixed.

We only drive this van occasionally, but have noticed that, each time we drive it, it will not back up until we have driven it for some time, and, even in drive, it feels as though the transmission is slipping. We still check the levels, and they appear to be good. Is there something that we are missing that would cause it to not go in reverse until after driven for some time, and to be slipping in drive (it continues to slip no matter how long we drive it)?

I have read about a product called Lucas Transmission Fix, which is said to stop transmission slip. Do you have any experience with this product?

Lucas Automatic Transmission Fluid Additive

Thanks in advance Marchelle,

Hi there Marchelle,

You are experiencing the first stages of automatic transmission failure I am afraid to say. Reverse gear is usually the first sign of transmission wear/failure. Once the transmission fluid gets hot it gets thinner and is easier to push through the transmission….and move the vehicle. You can try the additive, I have not used it before but it certainly wont hurt anything at this point.

They do say this about that Lucas product though “This product can not fix mechanical failures and torn seals.” Those types of products are great for preventing issues from happening, but don’t really “fix” anything. I have yet to find a magic liquid to fix a serious car problem.

I would also not recommend servicing the internal transmission filter or flushing the transmission either, since that can just make things worse! And if your mechanic drained out most of the old fluid when he did the seal replacement….that is probably why the reverse gear failed when you picked up the vehicle.

That old dirty gritty transmission fluid was acting like a sand paper abrasive against the bands/gear inside the transmission. Removing that friction/fluid and replacing with fresh clean slick transmission fluid….causes the gears to slip.

The only real cure at this point is probably a transmission overhaul or a total rebuilt replacement transmission…….or a used transmission from a local junk yard, but that one might be as worn out as yours.

Driving the van on a regular basis MIGHT extend the life of the transmission though. Cars are like people, they hate to sit up for long periods of time then get up and run around all of a sudden.

Blessings,

Austin Davis

I am contacting you regarding my 2002 GMC ENVOY. I tootk it to a shop here in Atlanta for overheating problems where my car was overheating a cutting off last a week ago Saturday. The owner happened to be there and told me she would look at it over the weekend and call me Monday to give me a diagnostic and a quote. I agreed.

Monday she told me that the car needed a coolant flush, thermostat, micro-v belt and water pump, and that this would correct the problem. She quoted me $700 to complete these repairs.

I picked up my car on Friday and the mechanics said everything was great and the car was running fine. I was followed home in my vehicle by one of the mechanics there, and drove him back to the shop nearly 10-15 minutes from my home.

About an hour oor two later I left my house to pick up my son from school. I got about 2 miles down the road before my car began overheating again. I was able to get it back to the shop when they told me that due to a water test (which they showed me the blue and green sample) I had a blown head gasket and needed to take my car to a dealership.

I want to know how I should proceed? I read your advice to another customer about cheaper options fo dealing with engine overheating problems — what should I do? I had my car towed back to my home until I could talk to some people especially after just outing $700 and getting nothing for it.

I also wanted to ask what you know and what you thought of thermogasket? Will this work for my car possibly?

I have a paid off truck and really just need to get another year or so out of it?

Any advice?

Roxanne

Hi there Roxanne,

My first piece of advice is not to listen to these yahoo mechanics! You don’t have a head gasket problem until someone can PROVE it. These guys are guessing…just like they did with their first diagnosis.

The best advice I can give you without being there to look at this vehicle myself, is have it TOWED to the dealership for a proper diagnosis. Just tell the dealer your symptoms and what is happening as you drive, but I don’t think I would go into details about the work you just had done. They will be able to see the new parts themselves, but for now …..you don’t want them to think you suspect a costly head gasket repair.

They should perform a pressure test of the cooling system and go from there. I do have to say that if the engine overheating AND you continued to drive the vehicle until the engine shut off……..that is NOT good at all for the head gasket and the engine itself.

It just takes a few seconds of overheating to due severe damage to these engines. Don’t add anything to your coolant/radiator until you get a firm diagnosis of a head gasket problem.

Blessings,

Austin Davis

Hey there! For the last couple of weeks I have been battling an issue with my 1992 GMC Sierra pick-up. The truck has a 5.7L 350 cu. in. motor and some mild performance mods. For some reason though, the truck has been dying on me from lack of battery power.

At first I noticed the voltage gauge on the truck beginning to decrease slowly. Well, eventually the battery completely drained to a point where not even jumping it would help. Immediately we figured it was the alternator, and even though we had already replaced it with one from Auto Zone, we swapped it out again. Several days later, the truck exhibited the same problem.

Tried jumping it again and nothing. So, we bought a brand new battery from AZ and put it in the truck. Same thing; days later it happened again. NO POWER! This round we replaced the battery cables with a brand new set from the dealer. With the battery fully charged (used a battery charger) we ran the truck again.

Everything was fine, but then a few days later, the battery drained again! Aside from replacing the aforementioned parts, we have checked just about all the charging systems wires and nothing has come up. Iam not leaving anything on overnight or during the day, so what could be wrong? I am at my wits end with trying to firgure this out.

Please help!
Sg

Hey there Steve,

Well, you seemed to have replaced just about all the parts of your charging system. I would want to run a full electrical system test on your truck to see what is going on…or NOT going on. I have a feeling either you are having a problem with the alternator not producing enough power to keep the battery fully charged. By chance did you replace the alternator pulley or did you swap your old pulley from your original alternator and reuse it on the new alternator?

I say that because I have seen different size diameter pulleys…..it’s rare, but a smaller diameter pulley will not turn the alternator fast enough. Just like on a 10 speed bike, the smaller the sprocket used produces more power but less revolutions.

Also, and what is really the problem here is you might have had a higher output alternator than what you were given as a replacement alternator. There is probably an option for a high output alternator, at least you should ask Autozone about it and see if by chance you were given the smaller out put alternator.

Lastly, I would want to run a “drain test” to see if you have anything that is draining power from your battery. A full electrical test should include:

1. Load test the battery
2. Check the alternator output
3. Check for an electrical drain
4. Check the battery cables and connections and grounds
5. Check alternator plug connector for corrosion and make sure all power from alternator is actually making it to the battery

Honestly Autozone is NOT the place to get this test done. They are fine with load testing the battery and checking the alternator OFF the vehicle, but they are not really trained to diagnose this type of problem with the parts installed on the vehicle….which is how the test should be performed.

Blessings,
Austin Davis

Reader Follow Up

Good morning Austin! Well, I have good news! I figured out the problem and the voltage is doing better. We are getting between 13-14 volts sustained. Apparently, the problem was with the alternator not being grounded due to the powdercoating on the bracket on the front of the motor.

I purchased a ground cable from Pep Boys and attached one end to the back of the alternator and the other to the frame. Immediately, we could tell the difference just in the way the motor was idling. Voltage jumped a good 2-4 volts at idle. We have been driving the truck around and have not noticed any more problems. I appreciate all your help, as without it I would not have began to think critically.

Have a great day!
Sg

Summary
2007 GMC Yukon XL Denali is a luxury sport-utility with passenger capacity of eight. It has four doors.

Price
MSRP: US$50,305
Invoice: US$46,029

What is New in 2007 GMC Yukon XL Denali?
Changes to 2007 GMC Yukon XL Denali include increased wheelbase, smother design, spacious interiors, powerful engines, and higher torque.

2007 GMC Yukon XL Denali picture (front view)

2007 GMC Yukon XL Denali picture (side view)

Introduction
2007 GMC Yukon XL Denali is a big vehicle and occupies prime position on road. Longer wheelbase with optional chrome aluminum wheels offers a bolder and different look.

Body Styles, Trim Levels, and Options
2007 GMC Yukon XL Denali is available in single trim of All-Wheel Drive. Options include touch screen navigation system, DVD rear seat entertainment system, rearview camera, satellite radio, or CD player.

Powertrains and Performance
2007 GMC Yukon XL Denali offers standard 380hp 6.2-liter V8 engine with six-speed automatic transmission and overdrive.

Interior Design and Special Features
Interiors of 2007 GMC Yukon XL Denali are spacious with three rows of seats. Foldable seats offer increased cargo space. Controls are simple and logical.

Safety Features
Safety features of 2007 GMC Yukon XL Denali include disc brakes, side-curtain airbags for all three rows, tire pressure monitor, stability control, and front airbags.

Driving Impressions
Powerful engines make 2007 GMC Yukon XL Denali zoom across. Gear movements are quiet and effortless. Transmission can be changed to manual.

Pros
Noiseless ride and powerful engines

Cons
Third row seats heavy to fold

Summary
2007 GMC Yukon XL 4WD is a sports utility that can seat nine passengers. It has four doors.

Price
MSRP: US$40,605-US$46,485
Invoice: US$37,154-US$42,199

What is New in 2007 GMC Yukon XL 4WD?
Major changes to 2007 GMC Yukon XL 4WD include stronger frame, increased power, better structural materials for quieter ride, and better fuel efficiency.

2007 GMC Yukon XL 4WD picture (front view)

2007 GMC Yukon XL 4WD picture (backside view)

Introduction
2007 GMC Yukon XL 4WD has a longer wheelbase and offers more safety and convenience features. Increased cabin space and differential exterior styling give a complete new look.

Body Styles, Trim Levels, and Options
2007 GMC Yukon XL 4WD is available in eight trims ranging from SLE-1 1/2 Ton to SLT-2 3/4 Ton.

Powertrains and Performance
2007 GMC Yukon XL 4WD offers standard 352hp 6.0-liter V8 engine or 310hp 5.3-liter V8 flexible fuel engine with four-speed automatic transmission and overdrive. It offers 14 to 15-mpg in city and 18 to 20-mpg on highway.

Interior Design and Special Features
Quality of materials of interiors is excellent. Interiors are very spacious with power-folding second row seats. You can manually fold third row seats for more cargo space.

Safety Features
Safety features include standard four-wheel antilock disc brakes, stability control with rollover sensor, OnStar telematics system, and tire-pressure monitor.

Driving Impressions
Composed handling, new suspension, and accurate steering offer smooth and quiet ride on 2007 GMC Yukon XL 4WD.

Pros
Excellent maneuverability and powerful engines

Cons
Third row seats do not fold

Summary
2007 GMC Yukon XL 2WD is a sports utility that can seat nine passengers. It has four doors.

Price
MSRP: US$37,805-US$43,685
Invoice: US$34,592-US$39,637

What is New in 2007 GMC Yukon XL 2WD?
Changes to 2007 GMC Yukon XL 2WD include engines that are more powerful, better interiors, better mileage, and more stable exterior.

2007 GMC Yukon XL 2WD picture (front view)

2007 GMC Yukon XL 2WD picture (side view)

Introduction
Differential styling with better design and additional options make 2007 GMC Yukon XL 2WD a better vehicle than its predecessor models.

Body Styles, Trim Levels, and Options
2007 GMC Yukon XL 2WD is available in eight trims ranging from SLE-1 1/2 Ton to SLT-2 3/4 Ton. Options include dual-zone climate control, power-adjustable pedals, rear parking assist, and audio system with eight speakers.

Powertrains and Performance
2007 GMC Yukon XL 2WD offers standard 352hp 6.0-liter V8 engine or 320hp 5.3-liter V8 engine with four-speed automatic transmission and overdrive. It delivers 14 to 15-mpg in city and 19 to 21-mpg on highway.

Interior Design and Special Features
Interiors are of better quality materials and offer excellent finish. Controls offer easy operation. Cargo space is substantial.

Safety Features
Safety features on 2007 GMC Yukon XL 2WD include standard tire-pressure monitor, four-wheel antilock disc brakes, OnStar telematics system, and stability control with rollover sensor, and optional head curtain airbags.

Driving Impressions
Powerful engines offer smooth and quieter ride due to excellent suspension systems. Accurate steering supports easy driving.

Pros
Smooth ride and better interiors

Cons
Third row seats prove heavy for manual removal

Summary
2007 GMC Yukon Denali is a luxury sport-utility and can seat eight passengers. It has four doors.

Price
MSRP: US$47,780
Invoice: US$43,719

What is New in 2007 GMC Yukon Denali?
Changes to 2007 GMC Yukon Denali include better exterior styling and spacious interiors.

2007 GMC Yukon Denali picture (front view)

2007 GMC Yukon Denali picture (side view)

Introduction
2007 GMC Yukon Denali is a huge vehicle and very exorbitantly priced. It does not deliver all that it promises. It has excellent towing capacity and can haul full loads superbly.

Body Styles, Trim Levels, and Options
2007 GMC Yukon Denali is available in single trim level of All-Wheel Drive. Options include XM satellite radio, GPS navigation, and input jack for iPod and MP3 players.

Powertrains and Performance
2007 GMC Yukon Denali offers standard 380hp 6.2-liter V8 engine with six-speed automatic transmission and overdrive. It delivers 13-mpg in city and 19-mpg on highway.

Interior Design and Special Features
Interiors are comfortable with heated leather seats, lot of headroom, and lumbar support. Dashboard and doors have lot of plastic features with little faux wood paneling.

Safety Features
Safety features include Stabilitrak electronic stability-control system, front and side airbags, passenger sensors, ABS braking, traction control, and tire-pressure monitoring.

Driving Impressions
Brisk acceleration with hauling capacity proves helpful in uphill rides. It offers driver shift control with ability to change transmissions manually.

Pros
Many safety features and excellent handling systems

Cons
Low mileage and cramped seating

Summary
2007 GMC Yukon 4WD is a sport utility with passenger capacity of nine. It has four doors.

Price
MSRP: US$38,475-US$43,555
Invoice: US$35,205-US$39,488

What is New in 2007 GMC Yukon 4WD?
New additions to 2007 GMC Yukon 4WD include a more powerful engine, better materials for interiors, and foldable seats until second row.

2007 GMC Yukon 4WD picture (front view)

2007 GMC Yukon 4WD picture (backside view)

Introduction
New look of 2007 GMC Yukon 4WD offers a more compact yet spacious SUV with excellent safety and interior features.

Body Styles, Trim Levels, and Options
2007 GMC Yukon 4WD is available in four trims ranging from SLE-1 to SLT-2. Options include keyless entry, dual-zone climate control, six-disc CD changer, power-adjustable pedals, rear parking assist, and audio system with eight speakers and a CD player.

Powertrains and Performance
2007 GMC Yukon 4WD offers standard 320hp 5.3-liter V8 flexible fuel engine with four-speed automatic transmission and overdrive. It delivers 16-mpg in city and 21-mpg on highway.

Interior Design and Special Features
Spacious interiors are of high-quality materials and have a perfect finish. It offers logical control layouts. Power folding of seats is possible until second row while third row seats require manual removal.

Safety Features
Safety features include tire-pressure monitoring system, stability control with rollover sensor, antilock brakes, and OnStar telematics system.

Driving Impressions
Precise steering, coil over shock suspension, and effective brakes offer admirable driving experience.

Pros
Smooth ride and powerful engines

Cons
Handling dynamics not too efficient

Summary
2007 GMC Yukon 2WD is a sports utility that can seat nine passengers. It has four doors.

Price
MSRP: US$34,675-US$40,755
Invoice: US$31,728-US$36,926

What is New in 2007 GMC Yukon 2WD?
Changes to 2007 GMC Yukon 2WD include spacious interiors, head curtain airbags, power-folding second-row seats and more powerful engines.

2007 GMC Yukon 2WD picture (front view)

2007 GMC Yukon 2WD picture (side view)

Introduction
Improved aerodynamics in exterior styling and increased interior space has made 2007 GMC Yukon 2WD a more preferred sports utility among other similar vehicles.

Body Styles, Trim Levels, and Options
2007 GMC Yukon 2WD is available in four trims ranging from SLE-1 to SLT-2. Options include rearview camera, navigation system, rear-seat DVD entertainment system, power liftgate, and power-folding second-row seats.

Powertrains and Performance
2007 GMC Yukon 2WD offers standard 295hp 4.8-liter V8 engine or 320hp 5.3-liter V8 engine with four-speed automatic transmission and overdrive. It delivers 15-mpg in city and 20-mpg on highway.

Interior Design and Special Features
Interiors are excellent with superb quality materials and perfect finish. Control layouts are at perfect positions and power-folding feature is available until second row-seats.

Safety Features
Standard safety features on 2007 GMC Yukon 2WD include tire pressure monitor, stability control with rollover sensor, antilock brakes, and OnStar telematics system. Head curtain airbags for all three rows is optional.

Driving Impressions
Quick acceleration, robust suspension, and tight turning circle offers easy maneuverability for 2007 GMC Yukon 2WD. Exhaust noise is little loud.

Pros
Excellent interiors and powerful engines

Cons
Third row seats not foldable