What the title says. I only seem to be having the problem occasionally below ~50mph. It usually does not happen at speed on the highway.
The two lights sometimes come on and off with each other, sometimes alternating, sometimes just one. Seems erratic.
While happening the O/D OFF will come on and off multiple times within a couple of seconds. Tranny does not feel like it's slipping at all, nice firm shifts in and out of O/D.
I think it might be a heat issue, but I do have an aftermarket cooler so not sure why. Transmission was rebuilt with heavier duty parts around 20k miles ago (that's when the cooler was installed). 137k on the truck total.
Will be doing a fluid change and flushing the cooler this weekend as well as changing the filter and installing a trans temp gauge.
Any ideas as to what I can look at while I'm in there? I'd like to adjust the bands but I have no idea how to go about doing so.