Rear balance shaft bearing failure in 1999 Chevrolet S-10

chevrolet
s-10

#1

Anyone else have an issue with the 4.3 V6 taking out the rear balance shaft bearing? Mine did it when I hit resume on the cruise and it down-shifted the transmission too far and within 3 seconds had over-sped the engine.


#2

That’s a new one. I’v e never heard of that type failure on a 4.3. They usually soldier on nearly forever with minimal fuss. Why did the tranny down shift too far?


#3

I do not know. Cruise had always seemed to work OK, but I had never hit Resume at 40 mph when I had it set at 70. I was enjoying the fast acceleration until I hit 55 and realized it was not going to upshift. I got cruise shut off just and the noise started. I drove it the 3 miles to my neices yard and parked it. By then the main and rod bearings were gone also. The 99’s had a balance shaft added between the banks to make the engine run smoother- not like my 91 S15 that shakes your pants legs at idle. For some reason GM decided to just use a bronze bearing at the rear, subject to extreme wear at high rpm. I ended up getting a new rebuild engine put in- took me 5 years to save up the money and the wait added more problems to fix.