Ive had this happen once before on the highway and this time I took note of all the gauges and circumstances. I was on 93S sunday night headed home doing about 70mph with a couple bikes in the back, maybe 800lb total. 180F coolant, 120F transmission (its right before the trans cooler, hottest fluid) and about 2200rpm. It suddenly dropped out of OD and revved up close to 2800rpm or so. playing with the pedal and the OD off button did nothing. I had to coast a little for it to go into OD again. Happened a few more times, now showing the trans temp light every now and again.
Anyone got ideas on what this could be? I did the OD trans temp sender right after the first problem. Also cleaned out the OD switch and put some dielectric grease in there. Only thing left that I see is the OD solenoid. Can that cause a false temp reading? Odd that Id coast and it would shift right away. Almost like a temp problem.
Wonder if the PCM is overheated in the engine bay?

 

sound like my symptons right after i had my tranny replaced. the flash code, and scanner, showed to be the temp switch. my tranny guy had me watch the scanner as he jiggled the wires. when he did the voltaged jumped around. it turns out there was a bad connection in the connector to the trnny temp sensor. i had a newer one soldered in place and replaced the temp senesor just in case. that took care of the dropping out of od, not going in to LU, and the tranny temp lite comming on.


john
95 slt, auto, 2 wd w/237k, cc, lb, cstm lthr seats( w/massagrs), billet tc, hvy duty tranny w/upgraded v body, 4.10's, 235/85 bfg commercials(19.46 mpg hwy), kdp tabbed, gov set to 2.8k, grnd stock pl, timin advanced, more boost, air shocks, more fun.

 

Make sure your brake light switch is not out of adjustment. If you apply the brakes O/D & Lockup will kick out.

 

Check the connector on the external trans sending unit for play. Vibration and any slack can cause it to fluctuate and if the trans light is coming on, the PCM kicks it out of O/D.