Warning! C7 8speed automatic failure

[Supertech]

While driving from Jacksonville Fl. to Chula Vista Ca. I suffered total transmission failure on I-10 in Jennings La. Fortunately was able to coast to an off ramp and avoid an accident. Turns out previous warranty work on the flex plate and driveshaft resulted in one of the transmission cooling lines being bent out of proper position which resulted in it rubbing against the muffler assembly. It apparently took a long time for it to eventually wear a hole in the line which resulted in loss of fluid which caused erratic downshifting and eventual trans mission failure. Fortunately this did not happen during a horrendous rainstorm which we had just driven through in heavy traffic or in an isolated area of highway.

Be aware if you have a Z51 3LT 8 speed automatic that if the cooling lines are worked on that their routing location is extremely critical. I had absolutely no warning that this was slowly happening. No audible noise, no alarms, no advanced diagnostic alarms. I had driven across Texas from Ca and previously several trips to Las Vegas, Laughlin with absolutely no problems. The car had been in the dealership for regular check before leaving for Florida and only had 10,000mi on the car.

Car is currently in Lafayette La. at Service Chevrolet and Cadillac awaiting parts from Lansing Michigan.

 

[Toms007]

That sucks the big one, but glad you shared and maybe someone else will benefit from your problem.