my 05 LLY does the same thing occasionally,not sure what causes it...i never had any trouble with my trucks and the 05 has 93k and her and still runnin..if you find the problem let me know....thanks and good luck
Here ya go JC. Sorry it took so long. We changed both transmission pressure switches, $46.64 total and the neutral safety switch/transmission range switch for $142.29 Approx $189.00 in all.
Keep in mind that the tranny fluid should be changes as well & we always use 2 quarts of Lucas tranny fluid! Thats additional of course,