Wouldn't say totally useless. My mechanic told me the stock transmission temp monitoring on my 05 doesn't activate the dash warning light until the fluid temp hits 280 degrees and that may be a tad late. When towing our fifth wheel the only time things got dicey was towing in the hills East of San Diego area heading to I-8. Saw 220 on the gauge and could SMELL it briefly, but the light never came on. Once off the steep grades all was fine and temp settled in around 180, ambient temps were high 90's.