Vehicle down shifted hard and dash board lit up. Wouldnat shift any higher than 4th or 5th gear. Fortunately we were only going about 35mph. If we would have been on the interstate as we had been the 2 previous days on our trip to Florida it could have been deadly. Brought the Tahoe to Ron Anderson GMC Chevrolet in Yulee, Florida on 3/18/25. The transmission valve body is the problem. As of today 4/11/25 we havenat heard another word and returned home to Michigan 3 weeks ago.