Service Slants

Motor, May 2004 by Savasta, Bob

Jeep

Rear axle leakage. Some 1999-2004 Grand Cherokees equipped with the Dana 44 rear axle (tag code 226RDA) may produce a fluid leak or weepage from the area of the rear differential. The condition occurs most frequently after a prolonged cold soak followed by a drive cycle in which the vehicle is started and immediately driven at highway speeds. According to Jeep, the leakage is most likely the result of residual fluid in the vent line being forced past the jiggle cap in the line due to the rapid buildup of pressure in the axle housing under the driving conditions noted. Installing a new fluid accumulator (Part No. 52070409AA) into the vent line should keep your customers driveway clean.

To install the accumulator, begin by removing the rear bumper fascia. Follow that up by removing the splash/stone shield from the left rear wheel housing. Next, remove the two nuts and one bolt used to secure the evaporative canister support bracket to the frame (if so equipped), then remove the bracket brace nut at the quarter panel and remove the bracket from the vehicle.

Continue the job by disconnecting the vapor hose elbow from the top of the evap canister, then swing the canister out of the way for a clear shot at the vent line. Cut the rear plastic tie securing the line to its bracket. Using a ruler, measure and mark 1 ½ in. from the end of the vent line, making sure you don't include the jiggle cap in the measurement. Now cut the vent line at the mark you just made.

Using the illustration above as a guide, install the jiggle cap into one end of the 1 ½-in. length of vent line while installing the other end into the quick-connect fitting on the fluid accumulator. Make sure the fluid accumulator is positioned so that its flow arrow is pointing toward the jiggle cap, as shown. Install the remaining portion of the vent line into the other end of the accumulator. Using a couple of plastic ties, secure the fluid accumulator at the metal fuel filler tube and fuel vent hose. Make sure the accumulator is positioned so it doesn't rattle against other components. Now reattach the vapor hose elbow to the evap canister and install the canister with its support bracket into the vehicle. To complete the surgery, install the splash/stone shield followed by the rear bumper fascia, then take to the road to confirm quiet operation.

GM Truck

Inoperative HVAC mode switch. Chances are good the owner of a 2001-03 GM midsize pickup or sport/ute (complete list on the next page) will come into your shop one day complaining of an inoperative HVAC mode switch, or a switch that gets stuck in the Vent position. When he does, head straight for the a/c control head and examine it and its vacuum lines for an accumulation of oil. If you see the lube, the transfer case vacuum switch has probably sprung a leak due to the expansion of the fluid as the case heats up during normal operation. A new-design switch with a beefier, more durable seal (Part No. 15664811) is now available to address the problem. Figure about .6 hour labor to R&R the switch, .8 hour if the truck has a skid plate. GM also recommends replacing any HVAC component that may have been contaminated by the fluid.

Vehicles susceptible to the problem include Chevy Blazers and S-10s, as well as GMC Sonomas, Envoys and Jimmys, all with the two-speed electronic shift transfer case.

Ford

Rear suspension noise. Ford says some of its 1999-2003 Mustang Cobras can give off a clunking or popping sound when the car is turned into or out of an inclined surface (think "driveway") at speeds below 15 mph. Ford says the problem will intensify as the incline becomes steeper.

The most likely cause of the noise, says the cannaker, can be nothing more complicated than loose or inadequately tightened rear suspension attachments. Here's a list of the items to check, as well as the respective torque for the fasteners:

Cadillac

Finicky fuel gauge, DTCs set. Some 2003 CTS models may show an Empty reading on the fuel gauge after the tank is filled to the brim. According to Cadillac, the problem is often accompanied by DTCs P0461 and P2066 being logged in computer memory. Normally you'd be thinking "bum fuel float" here, but the presence of the two codes helps suggest something else-like a software anomaly that sets up in the PCM when the vehicle is fueled with the engine running.

To begin the diagnosis, ask your customer if he sometimes fills the tank with the motor running. If he does, hook up your scanner and check for the presence of both of the codes mentioned. If one or neither code is set, continue with normal diagnostics for an inaccurate fuel gauge. If both are logged, you're dealing with the software snafu.

You may think Caddy has some new software files that can be zapped into the PCM to alleviate the problem. It doesn't...at least not yet. For now, just wipe out the codes and explain to the customer that refueling the tank with the engine running will likely cause the MIL to come back on.

One last but important point: This whole problem can be intermittent. In other words, the gauge can mysteriously start working properly on the next key cycle. The DTCs will still be there, but they'll have shifted from current status into history. Just wipe out the codes, and once again instruct your customer that refueling with the motor running is a no-no.