Outer Limits 4x4 Board

[size=18]Hi,
My Auto transmission (1990 Maverick tb42) gets stuck in first sometimes till I have to turn off the car to reset it. It happens after a bit of driving say 15 minutes or more. Have had the trans serviced and clean as a whistle but some electrical error codes are showing. The transmission was apparently fully rebuilt not long before I bought it. My trans place don't do that side of it and having trouble finding an auto electrician who has the tools to diagnose the problem.
Has anyone else had this problem and if so what is the cure?
Cheers
Steve
[color=yellow][/color][/size]

firstly why would you want it in size 18?

Now, where are yuo located to suggest places to take your car for repair.

Howdy, No idea what I have done there with the size 18, first time user.
I am located in Adelaide.
Cheers