'99 5.7 'burb, 4L60E, stock tranny cooler. started slipping a few months ago and just got around to throwing this stuff in there today. Put about 10 oz of lucas tranny fix in, drove it around for a little bit, seems to be shifting smoother but at different points... now my speedo is acting up. when I hit the gas, it takes about 5-7 seconds for the needle to move up from zero, and even then it moves very erratically and slowly. when I hit the brakes the needle will actually go up about 5mph, stay there for about 10 seconds, then eratically go back down to below the zero mark on the cluster. this is pissing me off, and I really don't need a speeding ticket right now because I don't know how fast i'm really going.