Doing the Research
Q: I have a '96 Chevy 1500 2WD pickup with the 5.7-liter V-8. I'm interested in finding all the recalls and service bulletins that involve this truck in case I need them in the future. Where can I locate this information?
A: It's a great idea to stay up to date on safety or emission recalls that may pertain to your vehicle. The best place to go is the National Highway Traffic Safety Administration (NHTSA). You can reach them at 888/327-4236, or better yet, check out the Web site at www.nhtsa.dot.gov. On the home page, scroll down to recalls and perform a search by entering the make, model, and year of your truck. You'll find several recalls that do apply, but remember this is basic information and not the complete service procedure. The best way to confirm that all applicable recalls have been completed on your vehicle is to go to the dealer with your Vehicle Identification Number, and let them do their own search on repairs or modifications performed. The NHTSA site is also a good source of information on crash-test results and automotive-safety related news. When dealing with Technical Service Bulletins, we suggest a search on your particular vehicle. This again will offer a brief description and not a complete service procedure. The complete TSB is published by the manufacturer and intended for use by the dealership technician.
Temperamental Speedo
Q: My '98 Jeep TJ has developed an intermittent problem. The speedometer and the tach keep cutting out randomly. I can go days without it happening before it starts doing it again. Do you have any ideas on this one?
A:The '98 Jeep Wrangler (TJ) and Cherokee (XJ) both were affected by poor connection at the instrument cluster. This condition may cause erratic operation of the speedometer, tachometer, and the airbag-warning light, along with setting a fault code in the Airbag Electronic Control Module. The connection problem is actually caused by oxidation at two of the male electrical terminals on the back of the instrument cluster assembly. DaimlerChrysler has come out with Technical Service Bulletin 08-20-98A. This bulletin gives detailed instructions on removing the oxidation with the use of a scraping tool and an electrical contact cleaner. The connection is then protected by applying a specified dielectric grease. We recommend having the job done at a Jeep service department. A poor-quality repair may result in damage to the instrument cluster and/or a repeat of the original problem.
Moving Up a Size or Two
Q: I recently purchased a Silverado 2500HD Crew Cab with the Duramax diesel. I wanted the dealership to install 285/75R16 tires in place of the stock 245/75R16s (too small for my tastes). The service tech told me I'd have problems with the ABS, and the "service engine soon" light would come on, as well as voiding my warranty. Hope you can help.
A: GM gas-engine pickups utilize a different system than those equipped with the Duramax diesel 6.6-liter V-8 bolted to the Allison 1000 series transmission. The Vortec engine Powertrain Control Module gives you the option of reprogramming the system to accommodate changes in tire size and/or rear-axle ratio. However, the parameters are limited to tires and gears that were originally available from the factory. Aftermarket performance reprogram kits, such as the Power Programmer III ($435) from Hypertech available for the 4.8/5.3/6.0L engines will substantially expand the tire size and gear-ratio limits, but this kit isn't available for the Duramax/Allison combination. Your 2500HD Silverado doesn't allow the limited tire-size program adjustments that can be performed at the dealer like the gas-burning Vortec-equipped trucks. But there's one aftermarket company that does offer a total performance-calibration program for GM trucks with the Duramax engine, which includes the option for significant tire-size adjustment. Pacific Performance Engineering (714/985-4825) has a sub-program available under the Duramaximizer package for about $895. Give them a call for further details. Swapping tires without the necessary adjustments may cause problems with speedometer calibration, fuel economy, ABS, and transmission operation. The installation of any aftermarket part can only affect your warranty if it's proven the modification was a direct cause of a failure.