Help possible tranny failure

[nanyiru]

Hi guys, i got this little problem, today i was driving to work and during a red ligth i detected that the battery charge was jumping and tended to go high,i guess this is related with my tranny because it only happens when the tranny is in drive, if i put the truck in park or neutral the battery charge gauge stops jumping so i think is some electric part on the tranny that is causing this.

If some have any idea of what could cause this i´ll apreciate your help.

Saludos desde Mexico!:exp:

 

[JAW]

is the battery light coming on under load..ie you have ac on, or opening and closing windows? or when trucks at a slow idol? Have you had the voltage regulator checked? I had same problem, and turned out to be VR. Swapped mine out for under $20, and my problem was solved. Worth testing it,

 

[nanyiru]

Tnks, ill check the VR and part from there!