OK, I have two problems with my 2003 4 door chevy blazer.
#1. I have a 2003 blazer that has been chirping from the transmission for the past year, I have not noticed any other sounds or slipping when shifting. It sounds like a bird chirping. When it started I thought it was a bird outside, I had the windows open and it seemed logical at the time. Oh yeah it’s an automatic.
#2. The lights on my 4x4 selection buttons are blinking and I can’t switch from 2 wheel drive. I noticed this after I jumped the car when the battery was died last month, I believe it’s unrelated to the first problem.
I’ve never heard of a chirping transmission, it there any chance the noise is coming from the serpentine belt. I’ve had new belts make a lot of noise on my 2000 Blazer. The quietest belt is the Good Year Poly-V.
The Blazer’s computer is sensitive to the battery’s state of charge. A few months back, my Blazer needed a jump. Afterwards, I noticed the idle was 150-200 rpm higher and the torque converter was not engaging. I checked the battery voltage (12.1 Volts - 25% charged), it was low. I used a charger to bring the battery up to 100% charge (12.6 Volts). The Blazer ran fine after that.
When the 4wd drive switch acts up on my Blazer, I disconnect the battery for a few minutes to reset the switch. I’ve been putting it in 4wd once a week or so and haven’t had any problems with the switch.
Ed B.