AfterMarketNews Brake&Frontend BodyShopBusiness Counterman EngineBuilder Fleet Equipment ImportCar Motorcycle & Powersports News Servicio Automotriz Shop Owner Tire Review Tech Shop Tomorrow's Tech Underhood Service Speedville

Servicing Mercedes-Benz AIRMATIC Suspensions

The Mercedes-Benz AIRMATIC suspension system was introduced in 1999 on the S-Class and has subsequently been used on the E-Class and most of the automaker’s SUVs. The system employs electronically controlled air springs that provide an ideal balance...

Read more...

Mazda: Performing Regular Undercar Maintenance

In this article, we’ll take a look at brake and undercar service on the Mazda vehicle lineup, with the footnote that even though this type of work ­becomes routine when you have a preventive maintenance mindset, good work habits from beginning to end...

Read more...

ZF 8-Speed Transmission Replacement

The ZF 8HP transmission made its debut in 2009, and since its introduction, has been one of the top choices for international car manufacturers. BMW, one of ZF’s largest customers, uses the 8HP across its entire product portfolio. BMWs featuring...

Read more...

GM Power Steering Noise/Leaks

GM: Power Steering Noise/Leaks from Power Steering Pump, Gear or High Pressure Hose During Extreme Low Temperature Conditions MODELS: -2009-2015 Buick LaCrosse (Equipped with Hydraulic Power Steering) -2010-2013 Buick Regal -2012-2015 Buick...

Read more...

Ford Edge Brake Replacement

Ford Edge Brake Replacement Basics The Ford Edge is an SUV based on the CD3 platform. The brakes on these vehicles are straightforward and do not break any new ground. There were no major changes to the brake systems from 2007 to the current model. For...

Read more...

Live-Axle Wheel Bearing Replacement

Replacing wheel bearings on a vehicle with a live rear axle may not be one of the most frequent jobs, but it can be one of the most profitable. While the basics have not changed in more than 60 years, new seal materials and differential designs have...

Read more...

The Ins And Outs Of Sanders

Sanders are required tools in today’s collision repair shop. Body techs and painters rely upon them every day to achieve that perfect finish on your customers’ vehicles. Whether you’re prepping a panel for paint or removing imperfections before...

Read more...

Are You Regularly Maintaining Your Equipment?

Technicians who are idling because the welder won’t feed wire, the hydraulic ram won’t pull chains, the booth heater won’t heat or the air compressor won’t compress enough air is a costly mistake, as labor time is the most expensive thing in any...

Read more...

Celebrate 'Back To The Future' Day By Watching The Time Machine Get A 2015 Detail

    For many today is just another Wednesday, but for a lot of people it is more than just your average Wednesday, it is "Back to the Future" Day. It is a day that everyone who watched the cult classic trilogy Back to the Future recognizes...

Read more...

Home Climate Control 4WD/AWD Hub Service On Kia Sportage And Sorento Models

Print Print Email Email

In the past 15 years, Kia four-wheel-drive (4WD) and all-wheel drive (AWD) systems have evolved from vacuum hubs and manual shifting transfer cases to fully electronic systems that use magnetic clutches for push-button operation. While you may never have to replace the entire transfer case or transmission on the popular Sportage and Sorento SUVs, you will have to replace hubs, sensors and solenoids on your customers’ vehicles. In this article, we’ll start with the early systems on the 2000 Sportage. 

The most common complaint you’ll encounter is no 4WD operation, which can usually be traced to problems with the vacuum-actuated front hubs. Kia requires that the driver shift the transfer case into four-wheel-drive, choosing either high- or low-range gearing. The driver must then flip a switch that opens a vacuum-control valve, sending vacuum to the locking front hubs and engaging them to the drive axles. If there’s a weak link in the system, it’s the hubs.

The hubs can cause a couple of problems. The first, and most common, is no engagement. Many times, these troubles can be traced to the vacuum supply, rather than a mechanical problem with the hubs themselves. The first step is to be sure you have vacuum at the hubs with 4WD engaged and the engine running. If not, work backward looking for the vacuum leak; a convenient test point is the “T” fitting by the master cylinder where the lines branch off to the left and right sides. This “T” is downstream of the control solenoid and vacuum storage tank, so if you have vacuum here, you should have it at the hubs.

Many times, the problem is as simple as broken or disconnected vacuum hoses leading to the hub. But, there have been reports of problems with the steel lines running to the wheels. Over the years, these lines can rust, restricting flow and, in the worst cases, causing leaks. There are updated parts available, and Kia has issued a TSB on the subject (see sidebar below), but line replacement can be a tedious task. Many techs report good success with alternate methods of repair, but you’ll have to make the choice as to what’s the best course of action for your situation.

Another problem you can run into with the hubs involves engagement when it’s not called for. Usually described as a noise, in this case the hubs are sticking, and the wheels are engaging and disengaging the drive, the axles and front differential while the transfer case is in the two-wheel-drive position. Many times, simply backing up the truck will take care of this problem, but often it’s an indication that the hubs should come apart to be cleaned and lubed.

Depending on the condition of the original units, replacement hubs may be in order. In the case of the Sportage, road grime that’s finding its way into the hub through the previously discussed vacuum system can cause this problem. If the 4WD isn’t used very often, the broken or disconnected vacuum lines could have been overlooked for quite a while.

REPLACEMENT HUBS

Should you find yourself in the position where ­replacement hubs are required, or if the customer values reliability over convenience, consider changing over to the almost-bulletproof aftermarket manually ­operated hubs.

These units provide a low-cost alternative to the automatic units and, while they require the driver to lock the hubs when 4WD is anticipated or required, many customers find it an attractive alternative.

If you do go with the manual hubs, be sure to seal any of the vacuum fittings to prevent ­debris from getting into the hubs, and disconnect the supply solenoid to prevent a manifold leak when 4WD is­ ­selected. It’s also a good time to service the wheel bearings or, at the very least, make any bearing adjustment that’s ­required.

The rest of the 4WD system on these vehicles presents more service opportunities than ­diagnostic challenges. Be sure to ­figure on changing the fluid in both differentials as well as the transfer case when doing a major service on a Sportage. Of course, any work on the hubs will have you also checking the brakes.

4WD & AWD ON LATE-MODEL KIAS

Looking at the later-model 4WD Kias, we see them moving away from locking hubs that engage the 4WD, and moving toward systems that de-couple the 4WD differential from the primary drive. 

After a short hiatus, the reinvented Sportage was back on the market in 2005. Kia made big changes, one of which was going with a lighter duty, crossover-type FWD platform ­vehicle that engages the rear wheels to provide AWD as needed with a driver-controlled, lock-up option. 

By looking at various sensors, the control unit decides when torque will be delivered to the rear wheels and at what percentage. By looking at ­individual wheel speeds and throttle position, brake input and steering angle, the control module will send a command to the rear differential-mounted coupler, applying the appropriate pressure to the internal clutch pack for the given conditions.

While the coupler handles the varying load, the continuously engaged, transaxle-mounted transfer case does the job of keeping the driveshaft spinning.

If the conditions require 4WD operation, the driver can choose to lock into FWD, providing the maximum 50/50 split to both axles. Designed for low-speed operation, the control unit will begin to disable the lock at 18 mph, and, at 25 mph, the lock system is fully disabled. As speeds come down, the lock feature will re-engage. Being speed dependent, if there is a problem with the wheel speed sensors, the lock option is disabled.

REPAIR ISSUES

When it comes to potential problems, most will be mechanical issues, noises or vibrations. Instead of two CV axles there are four, and you have to consider the driveshaft as the shakes and noises are diagnosed. The wheel bearings and hubs are no different than what we see on any 4WD or AWD vehicle. The only serviceable items in the coupler are the bearings.

If you’re faced with a blinking 4WD lamp on the dash, or a suspect a problem with the system, it will be difficult to go much further without a scan tool that has enhanced software that will give you ­access to codes and data. Even with the very good information on the free Kia service information site (www.kiatechinfo.com), you would be hard-pressed to have a successful outcome without the tooling.

With the transfer case mounted to the transaxle, when it comes to maintenance on the system, it’s easy for an inexperienced tech to think they share lubrication. That is not the case with the Kia and it’s important that the fluid level in the transfer case be checked and replaced on the same interval as you recommend for the transaxle.

THE SORENTO SYSTEM

The Kia Sorento models up to 2009 offered both a part-time on-demand system, as well as an optional full-time AWD system. We’ll take a look at the part-time system that Kia refers to as “Electronic Shift Transfer (EST),” that uses an electrically controlled transfer case as well as an air pump system to engage the front axle. This allows for shifting “on the fly,” from 2WD to 4WD, applying a fixed amount of torque. When in 2WD, the front “free running differential” is decoupled from the driveshaft, eliminating any noise or vibration while also eliminating the need for locking hubs.

When the 4WD switch is selected, an electric air pump is commanded on to pressurize the coupler, engaging the front differential pinion to the driveshaft, while the transfer case-mounted motor moves the shift forks. Then, finally, the magnetic clutch closes, providing torque to the front driveshaft. This is all controlled and monitored by the transfer case control module (TCCM). With either system, the ­vehicle has to be stopped to engage 4WD low range.

Like the Sportage, if the TCCM sees a problem, the 4WD lamp will flash. No tool is required to retrieve codes with the EST system. When no codes are present, turning the key on should result in the 4WD lamp lighting for 0.6 seconds as a bulb check, and then it will turn off.  If codes are present, the bulb check will be followed by a flash code in three seconds. There are seven codes available using ones and zeros. A short 0.5-second flash represents a zero, while a one-second flash indicates a one. The code will repeat itself three times; for example two shorts and one long flash is 001 (see flash diagram above).

There have been some problems with both the transfer case motor and air pump used for the differential coupler. That’s not too surprising, considering that the system spends most of the time in two-wheel operation. Sometimes, a simple tap on the transfer case shift motor or air pump will shorten the diagnostic process. Of course, a motor that comes back to life with a tap is certainly suspect and should be replaced, but that’s between you and the customer.

If you do find yourself diagnosing the front differential coupler, keep in mind that it operates on 5-8 psi, so don’t just put the shop air to it. When it comes to maintenance, the transfer case fluid is critical to long bearing and clutch life, so much so that transfer case oil pumps are used to keep it moving; be sure it’s checked and changed with the recommended fluid.

On all 4WD or AWD systems, tire size conformity is critical. The first diagnostic step for any problem should be to measure tire circumference. While the method doesn’t matter (we measure circumference with a narrow tape), just be sure they are the same size. Ideally, they will all be within 1/16”. Much more than that should bring up the discussion of tire replacement, especially if the problem involves binding or engagement issues in an on-demand system that appears to operate as expected. 

On automatic or AWD systems, tire size is even more critical as the system sees the speed differential of the tire size as slippage and adjusts accordingly. It’s easy to see how this would shorten the life of the clutches. This is why it’s so important that tires be replaced only in sets of four.

——————————————————————  

Bob Dowie has been in the automotive service business for 43 years, and his shop, Village Auto Works in Chester, NY, specializes in Honda, Toyota, Mazda and Nissan repair. Dowie owns and runs a Honda Civic and Nissan Sentra SER in SCCA GT Lite Class racing, and gets his technicians ­involved in various aspects of the sport.
  • Rich

    Is there anything in common between Sorento auto 4WD and the truck-based Borrego auto 4WD system? I’m having trouble finding 4WD information on a 2009 Kia Borrego!

Latest articles from our other sites:

America's Car Museum Celebrates 100 Years Of 'The Ultimate Driving Machine'

To celebrate 100 years of BMW, America’s Car Museum (ACM) is opening a new exhibit on May 7 – “BMW: Propelling a Century of Innovation” – to highlight some of the brand’s most gripping vehicles....More

Monroe ProSolution And Total Solution Brake Pads Now Available For Millions Of Additional Passenger Vehicles

Tenneco has expanded its Monroe Brakes product line to include dozens of new Total Solution and Monroe ProSolution pad sets offering combined coverage of more than 53.2 million additional late-model European,...More

Permatex Fast Orange Grease X Mechanic's Laundry Detergent Brings Cleaning Breakthrough For Service Pros

Permatex, a leading innovator in chemical technology for automotive maintenance and repair, has added a revolutionary automotive first to its #1 selling Fast Orange Hand Cleaner line with the addition...More

Federated Announces 4-Wheelin Car Care Sweepstakes

Federated Car Care Centers work hard to keep America’s vehicles on the road. As a thank you, Federated will award one lucky Car Care member with something they can use both on and off the road, a completely...More

ETI Announces New Officers and Board Members

The Equipment & Tool Institute (ETI) has announced its new officers and board members for the 2016-’17 term. Officers (one-year term) President – Bob Holland (Chief Automotive Technologies) Vice...More

Snap-on 18V Lithium Cordless Angle Grinder Features Safety Switch

The new Snap-on CTGR8855 18V Lithium Cordless Angle Grinder is the next step in grinders, similar to the CTGR8850, but features a unique safety switch that cuts off power if the tool is dropped. “We...More