Engine/Transmission (1994 - 1998) New electrical problem

[JClark]

Hello All,



I have a quick question. While driving to work today I noticed that my two-way radio was picking up a lot of engine noise. This radio has been working fine since it was installed in 1997 and it worked fine today as long as the engine was turned off. The music radio still worked like normal. Later in the day I noticed that my transmission (DTT with smart controller) was shifting different than usual. Then on the way home tonight the "GEN" light came on and it took a long time for the volt meter to go up to its normal position. The "GEN" light stayed on all of the way home (5 miles). Are all of these problems related to a worn out alternator or is there something else that I am missing? Why would the transmission start shifting differently?



Any help would be greatly appreciated and thank you for your time, John.

 

[DieselTweaker]

I could very well be your alt. check your grounds it's amazing how much havic a bad ground can play, but i would start with the easy thing's first get your alt and battery checked out make sure they are doing there job.

 

[Jschafer]

Did the truck still start ok?

 

[JClark]

The truck started fine all day yesterday. Have not tried to start it yet today. Once I can get away from work I will start checking the alternator and looking for any obvious problems. Thanks, John.

 

[Howard Durand]

Partsman pretty well summed it up. Make sure your battery connectors and all grounds are clean and tight. Look at the serpentine belt too.



The noise you are getting in the radio would indicate trouble in the alternator or possibly a loose connection that is arcing. Does it happen whether the truck is moving or not?

The transmission shifting funny, slow charging and gen light on would all indicate voltage problems.

If you have a voltmeter, disconnect each battery and check them out. You could have one battery that is going bad. They should each read around 13 volts fully charged.



Find a good shop that can load check the batteries and test the alternator output.



There is a remote possibility the PCM is involved. I believe it has the voltage regulator built into it.

 

[CRobbins]

I have had this problem many times. With engine running and "gen" light on, smack the alternator with a hammer just hard enough to get the gen light off. Then drive truck to your favorite alt/starter rebuild shop. Remove alternator and give it to them for brushes. That should be all that is nessasary to elimitate the problem. I have 305k on my alt and its had the brushes changed twice. Its cheap too, $20-35 depending where you go.



CR



PS - Hammer trick got me from Cali to Mi once.

 

[JoshPeters]

If you have a Voltmeter check the alternator for AC voltage output. It sounds to me like the Diode Trio went south in the alternator and it is starting to feed AC voltage instead of DC. AC voltage can make DC electronics act funny.





Josh

 

[JClark]

Hello again and problem solved.



I picked up a new alternator, installed it and all 3 of my previous problems disappeared.



Thanks again for your input and advice and have a nice weekend, John.