47-59 Help! 4L65E transmission (part of Connect & Cruise package) not shifting

[Chopped53]

Hi all. Looking for advice from the transmission experts on the forum. I built my '53 from the ground up with my dad, but we are more "tin tappers" than "wrench turners". I'm hoping you can help.

A few years ago, I got a "Connect and Cruise" crate engine package from the parts guys at the local dealer. It's a 350 with an 4L65e transmission.

Generally, it has been running great for four years and 10,000 miles since I finished my build.

But I have had an intermittent problem that bothers me. Two or three times over the last few years, the transmission seems to completely forget how to engage a gear. When I shift it into Drive or Reverse it will barely move. The problem seems to coincide with the spring season when I bring the truck out of winter hibernation. After letting it sit for a while and then trying again, it seems to figure out how to engage first gear but then it won't shift into second. After waiting awhile again, it decides to work properly and then it runs perfectly for a year or more. Weird.

It just did it again last weekend when I started the truck up for the first time since November.

Do you think it is an electronics issue or a mechanical issue? I believe the Connect and Cruise packages come with an electronic control module that is different from original. Maybe it takes time to wake up, or needs a reboot?

Have you heard of this happening before? Is it something to be concerned about?

Any ideas how to address the problem?

Thanks for your help.