Service Slants

Motor,  Mar 2004  by Savasta, Bob

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Cadillac

No Reverse engagement. Owners of 2003 CTS models with the 5L-40E transaxle may complain of a no-Reverse situation. According to Cadillac powcrtrain engineers, the problem may or may not he accompanied by an illuminated MIL, with DTC P0722 stored in computer memory if the light is on. An internal short in the pulse-width-modulated TCC solenoid could be the root cause of the no-engagement complaint.

To check things out, get the car on a lift and look at the serial number on the transaxle case. If it's 849522 or higher (build date 2/10/03 or later), continue with normal diagnostic procedures for a no-Reverse situation. If the serial number is lower than 849522, remove the drain plug and examine the transmission fluid. If it looks or smells burnt, the unit will have to come out of the car for a rebuild. If the fluid shows no signs of overheating, you'll need to remove the TCC solenoid and examine the build code number stamped into its plastic connector. As Fig. 1 shows, the solenoid is tucked tightly against the transaxle case, so you'll need to lower the valve body for a clear shot at the solenoid to remove it.

Begin the job by removing the transaxle pan and filter. Next, disconnect the harness connector from the TCC solenoid, then use a small pick to remove the solenoid's retaining clip. Using Fig. 2 as a guide, loosen the eight valve body-to-case retaining bolts. Now switch back to Fig. 1 and loosen the manual shift detent spring bolt. Continue loosening the bolts until the valve body drops sufficiently to allow adequate clearance with the case to permit you to pull the TCC solenoid. Caution; Don't let any of the bolts disengage completely from the case threads!

Remove the TCC solenoid from the valve body, then look at the build code number stamped into its connector. If it's 2690, the solenoid is probably shorted internally. Replace it with an upgraded, more structurally sound solenoid (Part No. 96042599). Reinstall the retaining clip, then reconnect the harness connector to the new solenoid.

Tightening the valve body bolts correctly is crucial to proper transaxle operation. If you tighten the bolts randomly, the valve bores could distort and cause the valves to stick. Torque the eight valve body bolts in the sequence shown in Fig. 2 to 97 in.-lbs. Now tighten the loosened manual detent spring bolt to the same value. Install a new transmission filter, followed by the pan. The pan gasket, by the way, can be reused if its not damaged.

To complete the fix, drop the car, fill the transaxle with fresh fluid, start the engine, place the shift lever in Reverse and check to see if proper engagement has been restored.

Chrysler

Brake pedal noise. Even brand-new vehicles have a few bugs here and there. A perfect example is the 2004 Pacifica, Chrysler's new crossover vehicle, which has a propensity for giving off an aggravating creak or squeak from the brake pedal whenever the driver applies the brakes with light to moderate force. Chrysler has already identified the source of the noise, as well as come up with a solution for it.

In a nutshell, the ruckus is caused by a bone-dry pedal return spring. A generous slab of multipurpose grease on all the coils of the spring should quiet things down. Hint: Once the grease is in place, work the brake pedal five to ten times to help it penetrate the coils. Repeat the exercise as needed until the noise is gone.

While you can obviously refer the customer to the dealer for this fix, you might want to tackle it yourself. After all, it's quick, easy, has a high degree of success and can't help but promote your shop as a top-shelf establishment.

Ford Truck

MIL on, catalyst DTCs set. Ford says that some of its 1998 5.0L Explorers are prone to illuminating the MIL and storing DTC P0420 (catalyst system efficiency below threshold-bank 1) and/or P0430 (catalyst system efficiency below thresholdbank 2) in computer memory.

In the past, either code usually meant replacing one of the cats. But Ford now has a cheaper solution-reflashing the PCM with some new files. You'll find the software update in WDS release B28.3 or higher. After the reprogramming is complete, you must fill out an Authorized Modifications Decal and affix it adjacent to the VECI decal.

GM

A/C system flushing guidelines. Apparently, there's lots of confusion in the repair community on the benefits of a/c flushing, at least from GM's perspective. Following are some guidelines regarding the hows and whys of flushing the a/c systems of GM s lineup of 1993-to-current vehicles:

First, a/c flushing should not be performed routinely just because something in the system takes a dive. GM points out that flushing takes a considerable amount of time to do properly, and is not necessary, or beneficial, for most common system failures. Conditions that do warrant Hushing include desiccant bag failure, a gross overcharge of PAG oil, refrigerant and/or PAG oil contamination or catastrophic compressor failure that results in PAG oil contamination.

GM says that system flushing will remove some of the metal particles that congregate in the system as a result of a catastrophic compressor failure, but is not completely effective in removing them all. So flushing should not be considered if removal of metallic debris is the only objective. GM continues to recommend the use of liquid line filters and suction screens to prevent gross system contamination and repeat compressor failure.