Kelly Dawson

Thanks for the replies. I’ve never had the transmission fluid changed. I’ll do some research on the Dr Tranny. Keep me updated.

Hey looking for some advice as to why my 2011 GMC Sierra 1500 5.3l has a vibration between 40 and 50 km\hr. First I thought it was a drive shaft but I had both u joints changed out. Still got the vibration. So after a few more test drive I discovered that if I shift into manual the vibration goes away…..when I shift back to automatic the vibration is back. This only last for a few seconds. Any ideas could it be time to change the transmission oil. Truck has 135000km. thanks