My Sierra has started hesitating when shifting from second to third, especially when the engine's cold, and it's been getting more noticeable over the past month. The dealer quoted me for a full overhaul that I can't really justify on a truck this age, and they didn't seem interested in looking for a simpler fix first. I came across alzaabiautocare.com/brands/gmc while trying to find someone who actually knows these gearboxes, but I'd rather hear from owners than trust a listing. Has anyone had similar hesitation on a Sierra and what did it turn out to be? I'm hoping it's a fluid or solenoid issue rather than a rebuild, but I'd rather know what I'm in for before committing to anything expensive.