Complete Axle Assemblies

RockAuto now has complete rear axle assemblies! Customers can now efficiently replace high mileage, worn, noisy, or damaged rear axles with a fresh, whole axle. These remanufactured axles are new to the RockAuto catalog and are available for select Chevrolet, Dodge Ram, Ford, GMC, Jeep, and Lincoln cars & trucks.

Find the Famous Brand complete rear axle assemblies in the "Drivetrain" category of the RockAuto catalog.

RockAuto on TV

Our friends on TRUCKS! have some nice things to say about RockAuto!

Video courtesy of PowerBlockTV.com

Forum of the Month

The Two-Sixties is a forum for owners (and potential owners) of the limited edition MG ZT. With the collective knowledge of its members this is the one stop shop for anyone owning a MG ZT 260.

The Car:
The ZT 260 is a fully engineered evolution of the front-wheel drive ZT. Clever installation techniques have permitted the larger capacity engine and rear-wheel drive power-train to be incorporated within the robust body-shell, without major visual changes. Below the skin, the platform is largely new with significant changes to many functional vehicle systems to accommodate the revised drive-line layout, producing a car of great driving character.

If you are the administrator or member of a forum and you would like to see your website featured in an upcoming newsletter and receive a discount code to share with your members, contact cynthia@rockauto.com.

Repair Mistakes & Blunders

The driver's side low-beam headlight went out on my wife's 2006 Toyota Prius. I went online and found that the proper procedure for replacement begins with, "Remove the front bumper..." Further research indicated that the bulb could be removed from the top. In order to do so, however, you need to remove the relay cover and basically work blind, unable to see the fixture. Need I mention that this is a halogen bulb that you need to be careful to NOT get your fingerprints on, lest the oils from your skin lead to premature failure of the capsule?

Now, I'm not a small man, and my hands are much like two small canned hams. After much twisting, contorting, sweating, crying, and bleeding I managed to get the original bulb out. I could see where the filament had burned out. It was pretty dark by this time, but I figured that since I couldn't see the socket anyway, I would go ahead and put the bulb in.

After another round of bleeding, scratching, and sweating, I got the bulb in and the assembly put back together. I turn on the light and, TADA!!!---it still doesn't work. Let the troubleshooting begin! Fuses are OK, wiring looks fine, multimeter says that I have power at the plug. Hmmm...I look at the packaging and see that the bulb is correct. Then I notice...I re-installed the bad bulb!

Thanks,
Jim in Virginia

Tell us about your most infamous auto repair blunder or unconventional fix. Use your woe to help others avoid similar mistakes or share off-the-wall solutions that worked (at least for a while!). Please email your story to flamur@rockauto.com. Include your mailing address and if you would like a RockAuto T-Shirt (please let us know your shirt size) or Hat if we publish your story. See the T-Shirts and Hats under Tools & Universal Parts in the catalog. The story will be credited using only your first name and your vague geographic location (state, province, country, continent, etc.) so you can remain semi-anonymous!

Automotive Trivia

To help lower gas prices, the governor of California recently allowed "winter gasoline" to be sold earlier than usual. What is the primary difference between "summer" and "winter" gasoline?

A. Summer gas has more ethanol. Ethanol increases octane and lowers certain emissions. The additional ethanol raises the cost of summer gas.

B. Summer gas contains less butane. Less butane means less gasoline evaporates and pollutes the air on warm summer days. Winter gas contains more butane. Butane is relatively inexpensive so winter gas costs less.

C. Summer gas must be 59 deg. F (15 deg. C) or less when it leaves the oil refinery. Additional summer-only restrictions work to keep the gas cool by controlling how long it can be in transit and stored at gas stations. Cooler gas in most cars' fuel tanks means less gas evaporates into the air and a denser fuel charge reaches intake manifolds leading to less pollution exiting tailpipes. The temperature and inventory restrictions push up the cost of summer gas.

Answer below

Have a Question?

“The Family Handyman” magazine’s Rick Muscoplat answers a customer’s question below about diagnosing intermittent A/C problems. The A/C Evaporator Core for late ‘90s Dodge trucks and Jeeps is one of RockAuto’s most popular parts, but Rick’s answer is interesting to all of us that are curious how a typical modern A/C system works!

Tom Taylor
RockAuto.com

Q. (Bernie in Kansas) I have a RWD 1999 Dodge Ram 1500 Sport Quad Cab pickup with the 5.9L gas engine and automatic transmission. I replaced a leaking evaporator core in the dash, pulled a vacuum and recharged it with the correct amount of refrigerant. It blows cold air but then starts blowing warm air. The compressor stops cycling when that happens. The next day it will blow cold again and then warm. I’ve replaced the low pressure switch but that didn’t fix the problem. I don’t want to keep replacing parts. What do you think it is?

A. Bernie, there are basically three sections to the A/C system; the sensors (high and low pressure sensors and the A/C on/off switch), the command unit (the powertrain control module- PCM), and the “doing” components (the compressor clutch relay, compressor clutch, and the compressor). The sensors inform the PCM if system pressures are too high or low. And the low pressure sensor provides the information on when to cycle the compressor on and off. Based on that information, the PCM toggles a ground connection to the control coil on the compressor clutch relay—the unit that actually powers the compressor clutch. Finally, there’s the compressor clutch and compressor.

Since you get cold air on occasion, we can assume the compressor clutch works at least some of the time. When the clutch stops cycling, the first thing I’d want to know is if it’s getting power from the compressor clutch relay. You can check that by removing the electrical connector from the clutch, starting the engine, turning the A/C to MAX, and testing for battery voltage on the dark blue/black wire. If you see voltage there, check the other wire for good ground. The ground for the compressor clutch runs on a black/white wire from the clutch connector to a splice on the top of the transmission. From the splice, the ground continues and terminates at the front of the engine. If you’re getting power and ground at the clutch connector but the clutch isn’t engaging, you most likely have a bad clutch. My guess is that it’s heating up and creating an open in the clutch coil winding or the connector. If you’re NOT getting power at the clutch connector, then I’d check the compressor relay to see if it’s actually getting a ground connection from the PCM.

Power flows to the compressor clutch relay contacts from fuse J (10A) in the power distribution center (PDC). Power flows to the relay control coil from fuse 11 (10A) in the junction block in the left kick panel. Remove the compressor clutch relay, start the engine, and turn the A/C to MAX. Check for battery voltage on terminals 86 and 30 in the relay socket. If you’re getting voltage, check for PCM ground on terminal 85 in the same socket. Good ground on terminal 85 means that the high and low pressure switches, the A/C control switch and the PCM are all working properly, the PCM is asking for compressor operation and providing the proper ground for the relay control coil. If you’re seeing voltage and ground, try swapping the relay with another one with the same part number. Then check for power at the compressor clutch connector again. If you still aren’t seeing power at the clutch, you may have a corrosion issue inside the PDC, or an open in the dark blue/black wire going to the clutch.

Now, if you’re NOT getting ground on terminal 85 in the relay socket, then the PCM isn’t seeing the proper input from the sensor switches. Here’s how those sensors work. The PCM supplies power to the A/C switch in the heater control head on the light green/white wire. When you turn the A/C switch to ON or MAX, the switch completes the path to ground on the black/orange wire terminating in the center of the dash. The PCM sees the voltage drop and that’s its signal that you want A/C. Next, it checks the high and low pressure switches. It sends power out to the low pressure switch (located on the top of the A/C accumulator) on a brown wire. If the refrigerant pressure is above the low limit, power flows through that switch and out to the high pressure switch (mounted on the back of the A/C compressor) on a dark blue wire. If the refrigerant pressure is below the high pressure limit, the power flows out of the high pressure switch on a light green/white wire and terminates at the A/C switch in the control head. So the path goes from the PCM, through both the low and high pressure switches, through the A/C switch and to ground. The PCM is basically looking for continuity through the sensor switches and then to ground. If everything is working properly, the PCM will see almost 0 voltage on that circuit. That’s its clue to provide ground to the A/C compressor clutch relay.

The system must have at least 43-psi at the accumulator to close the contacts in the low pressure switch. With the contacts closed in both the low and high pressure switches, the PCM provides ground to the A/C compressor clutch relay. The high pressure switch contacts open at 450-490-psi and close again at 270-330-psi.

So the most likely suspects are: intermittent compressor clutch coil, bad compressor clutch relay, corrosion in the PDC, open in the wire to the compressor clutch, intermittent ground on the sensor side.

Have a question about a challenging car repair? Rick Muscoplat is a former ASE Master Technician who was also certified in Advanced Engine Diagnostics (L-1). Currently he writes the automotive section for “The Family Handyman” magazine. Rick has kindly offered to answer some technical questions from RockAuto customers. He cannot answer all questions but will pick a few that are likely to also be of interest to owners of other makes and models. If you have a repair question for Rick then please send it to flamur@rockauto.com. Be sure to include the year, make, model and engine for the vehicle your question is about.

Please note Rick does not work at RockAuto. He cannot answer questions about shipping options in Europe, core returns, etc. Accurate diagnosis of a remote vehicle based on a single question is difficult or impossible. Please view Rick’s answers as simply ideas that might help you better develop your own diagnosis and repair strategy.

Here's my daily driver, a 1979 VW Transporter. I bought it three years ago as a non-running, multi-color mess. It was previously used by a theater group out of Boston to haul the troupe around until the required repairs were more than they had the skills or funds for. When I got it, my daughter named it Ducky so when it came time to paint it, the only reasonable choice was bright yellow.

Having RockAuto as a parts source for CV boots, ignition parts, injectors, and other needed engine bits saved me big money and time. Thanks RockAuto for making this project wrap up quick and easy!

Scott in New Hampshire

© 1999-2012 RockAuto, LLC - Madison, Wisconsin USA. RockAuto name and logo are registered trademarks of RockAuto, LLC. Manufacturer names and logos in the RockAuto catalog are trademarks of their respective companies and are used only to identify their products. All rights reserved.