Silverado shift cable issue


#1

2001 Chevy Silverado - shift cable broke a year ago. Had it replaced at the dealership because I didn’t want anyone to set off the air bag accidentally. A year and a few days after that fix, it is broken again. The original equipment lasted 9+ years, but the replacement only lasted a little over a year (just outside the 12 month 12,000 mile warranty on GM parts).

No one at the dealership could give me an explanation as to why the second one failed so soon, even though the replacement part is the same part as the original (I specifically asked them if it was, and they said yes).

Does anyone have any explanation for this? It would seem that the replacement part should last for about as long as the first cable. I would like to write a letter of complaint, and would like to know if my thoughts on this are justified.

Thanks for thinking about this.


#2

I have a buddy with a '96 1500 (about 250K miles), and he’s still got (almost) all the original cables and other parts. Rebuilt transmission a couple years ago, and a couple fuel pumps, but that’s it. Seems to me that maybe this one is/was either installed incorrectly, and has a kink or something somewhere that’s causing it to break, or there’s something wrong with the tranny, forcing very hard shifts.

Chase


#3

Once the cable is replaced, the transmission shifts into each gear smoothly - just as it should, so I don’t think the problem is in the tranny.


#4

How exactly does the shift cable fail? Does an end come off? Does the shifting become stiffer until you can no longer move the lever? If the latter, have someone disassembled the unit and eyeball the failed area. Describe the failure.

Hope to Help.


#5

The shifting becomes stiffer until it will no longer move. It happened after I was away for a long weekend at my daughter’s house and left the truck sitting outside while I was gone.


#6

This may be remote possibility. Check the ground wire between the negative battery terminal and the engine block. Look for corrosion at the terminals and heating effects at the junction between the terminals and the wire. If you have a VOM or DVM set the range on 12 volts DC; negative lead on the negative battery post; the positive on a good ground point on the engine; and crank. If you see more than 0.5 volts, recheck the ground wire or just replace the negative cable from the battery to the engine block.

I seem to remember a troubleshooting case where the starter was finding a ground through a shifter cable overheating the cable and sheath. I think GM uses a plastic liner inside the shifter cable that might melt and fuse if it got too hot.

Hope this helps.


#7

As soon as I read your reply, I went out and checked the ground. I was alone, so I couldn’t check it by cranking. My voltmeter is digital and reads to two decimal places. I checked the voltage across the battery terminals, and then checked it from the positive terminal to the ground post on the engine (the truck has a seperate place to hook up jumper cables away from the battery). The readings were identical to two decimal places.

Does this way of checking prove a good ground connection at the engine?


#8

A voltage drop caused by resistance will not show up unless current is flowing. In this case, the starter draws 150-300 amperes. This current flowing through the cable from the negative battery terminal to the engine block is what will cause the voltage drop. If that path was blocked, i.e. open, and the current were passing though the shift cable with a 1 volt drop there would be 150 to 300 watts of heat being generated in the shift cable. So depending on how long the starter had to crank before the engine caught, that would be the time of shift cable heating.

If you need to keep the engine from catching before the capturing the voltage drop, you might have the second person hold the gas pedal down (do a flood clear); disable the ignition system; or pull the fuel pump fuse.

HTH


#9

Thanks again. I will do the test you suggest this weekend when my wife and I both have the time to do this.