Dr. Gizmo: At home transmission replacement hits a snag

I own a 2005 Chevrolet Impala with a 3.4-liter engine and a bad transmission. It has 178,000 miles. The transmission was slipping and the check engine light was on. The fluid was as black as coal and smelled putrid. I decided I would replace the transmission at home. Now, I’m not so sure I should have taken on the job and I’m about to give up.

I installed a used transmission from a salvage yard. The installation went without a hitch, but the transmission did not engage unless I revved the engine. Once I revved it, it engaged with a bang. Once engaged, it shifted fine.

Since it was not operating properly, the salvage yard exchanged it. This one is doing the same thing. What do you think I’m missing? – S.S., email

I understand how frustrating this must be, but you will prevail. Replacing a transmission at a repair shop is not fun and games, but at home it can be miserable.

It’s not likely the transmission has a fault. It’s time to look for another cause. This issue likely has to do with the flow of transmission fluid. There might be an obstruction in the transmission cooler lines or cooler. Since the original transmission was toast, it’s possible debris is lodged in the lines and cooler.

Since you are resourceful, temporarily bypass the cooler lines. The transmission will likely operate as designed. If so, it is likely the cooler needs replacement. Surely the lines will need flushing and the transmission fluid should be flushed as well.

I have a strange problem that shops in my area have not been able to fix. The trunk pops open all by itself in my 2012 Chevrolet Cruze LTZ.

There are two ways to electrically open my trunk: I can use the button on my fob or a button at the trunk lid. Both work fine. There is no button or switch inside the car.

The problem is the trunk sometimes opens when I open or close the driver’s door. When this happens, I have to get out of the car and close the trunk. I might need to do this three of four times before the trunk remains closed. This might happen for a couple of days in a row. Then it might not happen again for a couple of weeks.

I’ve been to three shops, including a dealership. The trunk never acts up for them and there are no codes to give them a clue as to what might be wrong.

Have you ever heard of anything like this? – T.L., email

This, indeed, is an unusual case. A search of professional web sites did find a case similar to the issue of concern. In that case, the fix was to replace the switch at the trunk. The servicing technician also needed to repair a water leak as water was getting into the switch. Once the two fixes were applied, the condition was cured. Apparently, water entering the switch was wreaking havoc with computer modules.

In the morning when placing the shifter lever in my 2003 Ford Explorer Eddie Bauer into reverse, it engages and then disengages. Then it engages and stays engaged until I shift into drive. When in drive, the transmission shifts normally. Also, once the engine warms, there is no problem with reverse.

I went to a shop. They checked for codes. There were no codes. They also changed the fluid. This made no difference. Now they say with 236,000 miles, it would be necessary to replace it.

I don’t want to get rid of my Explorer. It’s in great condition. Is this the only option? – C.R., email

It may not be time to replace the unit, but certainly with the stated mileage there is wear of all the parts. Having said this, it would not hurt to inspect the valve body within it. Solenoids, valves and valve bores control the operation of the selected gear range. It’s highly likely one of the valves is not sealing due to wear, or perhaps there is a failed gasket or seal. If so, there is no need to replace or overhaul the transmission. The valve body might need replacement.

I hope you can help. I have a 1998 Chevrolet K1500 Silverado with a 5.7-liter engine and an alternator that will not charge. My truck as 212,457 miles and has been well maintained.

The trouble began with a dead battery. I had the battery and alternator tested. The battery passed, but the alternator did not with only seven volts. I bought a factory original alternator from a dealership and installed it. The truck started the following morning, but the battery died later in the day. I jumped it and had the alternator tested. It is charging 10 volts. I took it to a shop where they did a bench test. It passed.

I checked all the fuses and made sure it is connected correctly. The fuses are fine. I did not find any bad or incorrect connections.

Why would it charge during a bench test and not in my truck? What’s wrong? – P.M., email

Since the new alternator passes tests, there is a lot more to check. Check connections to the powertrain control module for loose and corroded terminals. Make sure ground connections are free of corrosion and secure. Correct issues as necessary.

It’s also possible the powertrain control module or the instrument panel has a fault. Both of these are in the alternator charging circuit.

If you do not find an issue with a conductor, consider a trip to a repair shop where an experienced technician will probe the powertrain module and instrument cluster for faults.

The heater blower in my 2013 Ford F-150 with 136,000 miles was making noise. I decided to replace it, but when I removed it, I found a part from something stuck in the fan of the motor. I removed it and reinstalled the motor. Now the noise is gone. Everything seems to be working OK, but I’m concerned that something else in the heater is broken.

Do you have any idea what might have been stuck in the blower? If something is broken what will it take to fix? – A.N., email

Without actually seeing the object, it is difficult to determine what you found. Be this as it may, there are doors in the duct work that are controlled by actuators that control the direction and volume of blended air flowing through the system. It’s possible what you found was a chunk from one of the doors. If so, you might have noticed a change in the force of air blowing from a vent, but if the piece was small there may not be any noticeable difference in air flow or volume. As long as everything seems to be working normally, there is no need for concern.

As for what a technician might need to do to probe the ducts, he or she might be able to determine what broke with an inspection camera. If repair is needed, the entire dash and heating system might need removal to replace the broken part. It’s a labor intensive repair. Definitely seek more than one estimate for this task.

Dr. Gizmo,

My wife has a problem with the left rear door in her 2011 Nissan Xterra 4X4. When she tries to open it from the exterior, it will not open. The only way to open it is to lean over the driver’s seat to use the handle and push the door open. All the other doors work properly.

I’m hoping this is an easy fix. Have you ever heard of this before? – A.S., Algonquin, Illinois

Yes, indeed. This might be caused by a faulty power door lock actuator, but it’s also possible an actuator rod on the exterior door handle has come off the handle. Sometimes, the handle breaks inside the door. To find the cause, a technician removes the interior door trim panel for a visual inspection of the handle, latch assembly, actuator rods and power lock mechanism. Also, he or she does electrical checks.

Thankfully, the door opens from the inside. This gives you an opportunity to check the position of the child lock. Make sure it is in the full lock or unlock position. Sometimes, if it is in the middle position, the door latch assembly does not work as designed. Also, try a shot of penetrating oil on the latch assembly. This might cure the issue if a mechanism is stuck. If these suggestions do work, you might get a hug from your wife. If not, it’s time for her to head to her favorite shop where she can hug the technician who fixes the trouble.

• Readers may send questions to Dr. Gizmo at P.O. Box 548, Cary, IL 60013 or Information is available on his website,

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