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Depending on your suppliers

The service bay is the front line in our batter, and we depend on those who supply our tools and parts.
Friday, October 1, 2010 - 00:00

The service bay is the front line in our batter, and we depend on those who supply our tools and parts.

Motor Age Garage 1994 Ford F150 transmissions transmission won't shif fixing vehicle repair shop training technician training automotive aftermarket

Bobby is a guy I know who served in Vietnam, and one day he had just finished an uneventful 12-hour patrol standing behind a .50 caliber machine gun on the back of a military vehicle. When he field-stripped the weapon to clean and oil it for the next man who would finger the trigger, he discovered that he had spent 12 uneventful hours behind a weapon that had no firing pin – it wouldn't have fired a single shot if he had come under fire by the enemy.

Faulty parts and tools have disappointed everyone who has worked in the business of fixing vehicles.

I've seen clutch discs come right out of the box with so much lateral run-out that the clutch wouldn't release. I've seen a new name-brand Idle Air Control (IAC) valve with an internal short that fried the IAC circuit in the PCM on a Lincoln. (I wrote two letters explaining how their part had caused the problem, but they never reimbursed my parts supplier for the PCM or the faulty IAC valve.) I recently purchased a remanufactured Mazda Miata PCM from a supplier in Miami only to discover that the PCM was remanufactured in such a way as to be incompatible with the Miata's immobilizer module — and the rebuilder absolutely refused to make it right.

And I once installed an ignition switch on a 1993 Ford Ranger with an internal short that burned up a small ground wire the first time the switch was turned to the start position.

A few weeks ago, we installed a Throttle Position Sensor from a local parts chain, and the sensor was as dead as a hammer; it simply interrupted the reference voltage and wouldn't put out any signal at all.

There are cooling system thermostats that open at 130 degrees when they're rated for 196. There are bad "remanufactured" alternators (I saw four in a row from one parts store), and there are steering and suspension parts that just don't fit right even though "that's the only one listed."

I've seen name-brand radiator caps still on the display card with their return valves dangling (the return valve isn't supposed to do that, by the way). Readers might remember my story about two bad ignition modules that passed my way across the parts counter at my local parts supplier.

Neither of them would start my 1980 Ford pickup, even though the parts store's very expensive module testing tool showed one of the modules to be fully operational. It was interesting to see a parts store experience tool failure. (If you don't remember that story, you can read more about it in our April 2008 edition at

Speaking of faulty, untrustworthy tools, I bought an expensive name-brand 11 mm line wrench once only to have it break like a cheap toy as soon as I applied the least amount of torque. On another occasion, I bought a very expensive air hammer from a tool truck guy only to hear just the hissing escape of air when I pulled the trigger. And there are the electronic tools that are supposed to be the latest and greatest but don't give reliable results.

When we place our trust in bad tools and parts, the people who manufactured those tools and parts sometimes seem fairly callous to the fact that our misplaced trust cost us and the shop time and money.

The Caravan Fiasco

We checked a 2005 Dodge Caravan that illuminated its ABS light, but we saw no codes at all with our expensive and freshly updated scan tool connected. A peek into the datastream showed a dead right rear wheel speed sensor, and because we saw nothing wrong with the tone ring or the wires, we threw a sensor at it to no avail.

These Magneto-Resistive sensors don't put out an AC voltage. They're fed with a 12-volt bias and they switch current (seven to 14 amps) to indicate wheel speed. The current switch is kind of difficult to measure if you don't have the right tools to do it.

Suffice to say that we checked the wires to the ABS module and then carefully transposed the signal from the two rear sensors by switching the wires in order to determine whether or not the module could even see a sensor on its right rear channel. After this maneuver, according to our scan tool, we lost both sensor signals.

This kept getting better. After replacing the module to be rewarded with a flashing ABS light, one of the guys read that the module was supposed to be "initialized," so I drove the van over to a friend's shop where his DRBIII revealed that the Caravan had two codes for the left rear sensor and a missing left rear sensor signal. Our scan tool had been unable to retrieve the DTCs and then had told us the right sensor signal was missing, which was patently false.

After finally successfully completing the repair, I contacted the scan tool manufacturer and they simply told me I should have contacted their tech support. Well, I thought I could trust the tool (Shouldn't I be able to?), and an ABS module was replaced as a result. The fact is that I never saw the need to contact the scan tool tech support until after the fiasco was resolved.

Jeeped by a Water Pump

We ran across a 1990 model Cherokee with a leaky water pump and, after replacing the pump, the Jeep developed an overheating problem. An exhaustive investigation ensued that took us right back to the pump we had installed. Some of those Jeeps have a left-spinning pump (driven by a V belt) and some have a right-spinning pump (driven by the backside of the serpentine belt). I wondered if we had installed the wrong pump.

Well, we found that we didn't install the wrong pump, but the second replacement pump had less clearance between the pump impeller and its reaction surface than the first replacement pump. Further, it was evident that the impeller on the second pump was pressed farther onto its shaft.

I saw this irritating anomaly for the first time back in 1984 when I put a water pump on a Plymouth slant six that ran hotter after the pump swap than it had before the leaky pump was replaced.

The F150 Transmission Adventure

This customer's concern happened all at once. He backed the Ford up to the porch, loaded it with some camping equipment and found that it wouldn't pull away from the porch in forward gear. Also, he noted that the transmission fluid had been changed to no avail.

This transmission came to us before the truck did, because the owner removed it and brought it to us with the idea that we could throw a set of clutches and seals in it and get it going. Yeah, right. The situation reeked of trouble, but I had a guy who was willing to make a go of it, and so he dove in. But I quickly advised the owner to bring in the truck so we could reinstall the transmission and make sure it worked when we were done with it.

Making his way through the innards of that E4OD, my technician found that the forward clutches were fried and the intermediate servo piston was slightly bent and had a shredded seal. The replacement servo piston was a different style and required the removal of a snap ring and retainer plate.

With everything reassembled, a turbine play check on the converter revealed enough clearance (about .08 inch) to warrant replacement of the converter. The customer took the torque converter to see if he could locate another one (he didn't like the price I quoted). He brought a rebuilt converter back about a week later, and we installed the transmission only to discover that it wouldn't pull because it had no fluid pressure at all.

What had my guy missed? Removing the transmission, we disassembled it once again and rechecked everything. We disassembled the pump and did a close inspection of the gerotor assembly, then made sure the valves in the pump housing were installed correctly and moving smoothly in their bores.

After that, we re-examined all of the check balls and went through the valve bodies to find and repair a stuck line pressure control valve in the small unit that piggybacks the main control assembly.

We also eliminated the solenoid body as a problem (which contains the EPC solenoid) by replacing it with a known good one, but nothing we did would garner any fluid pressure at all. Finally, with the transmission oil pan removed and a piece of paper held against the fluid pickup on the filter, I had my student Johnny start the engine for a few seconds and found that the pump (which we had primed carefully with oil to make sure it wouldn't spin dry) wouldn't even attempt to pick up even the piece of paper, let alone any transmission oil. The pump wasn't in any danger during that maneuver; the converter wasn't even driving it.

With the torque converter removed once again, I had the owner bring the original converter back to the shop. We found that the torque converter he had picked up at the parts store was for a different transmission. But the aggravating thing was that it seemed to fit when Johnny spun it into place. It was, however, shallower than the E4OD converter and disengaged from the transmission fluid pump when it was bolted to the flywheel. Finally, a side-by-side comparison of the converters told the tale. The parts house investigated the mix-up and said the converter was boxed wrong. This was a perfect storm; if we would have had the old converter on hand we would have caught the error right out of the box.


There are thousands of labor hours lost every week in our nation's service bays, and many of them are hours you just can't ethically charge to a customer. In too many cases, the technician is expected to absorb the loss.

Furthermore, when we find ourselves stumbling over those bad parts on the way to what would otherwise have been a more profitable ticket, we deserve more than the dismissals and excuses we often get by those whose shoddy work routinely impacts our bottom line. Our customers expect us to do good work, and we should be able to expect the same from our parts suppliers.

The point is that in this increasingly challenging industry, the one thing we desperately need to believe is that we can count on our parts, the people who build them and their suppliers to be dependable. And let's not forget the folks who pull the orders and ship the parts. The last thing we need to hear is that somebody forgot to put it on the truck, which could spawn a whole new discussion if space permitted.

Richard McCuistian is an ASE-certified Master Auto Technician and was a professional mechanic for more than 25 years. Richard is now an auto mechanics instructor at LBW Community College/MacArthur Campus in Opp, Ala. E-mail Richard at

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