Is my tranny goin out! Help!

[s.hiles]

Ok so was driving my truck on the highway today for the first time in awhile. Seemed like itwas goin in and out of lock up or in and out of OD. It was uncontrollable, would be going 50 to 65 and it would just shift in and out of the gears no change of he throttle. Have the TW chip and tried all the settings no difference. Have the BTS valve body to with a stock tranny.

Any ideas? Please help

[backwoodsboy]

The truck was going from 50-65 on it's own, or you were accelerating from 50-65?
Check your brake lights. The TC unlocks when you tap the brakes, so a brake light shorting to ground will make it unlock and lock on its own.

[s.hiles]

I would be goin one steady speed between 55 and 60 and of would just switch in and out, no brakes or throttle change. And I did just add a tailgate light bar and change my reverse lights to leds

[kramarj]

I put led tail lights in my dad's work truck with a utility box and they constantly drew power which told the pcm the brakes were on, which wouldn't let it shift into OD. We just switched back to incadescents. Maybe the leds are doing it somehow?

[s.hiles]

Ill try switching back and see, its just so strange

[backwoodsboy]

If I was a betting man, I'd put money on install of the new lights being the issue.
Hard to tell for sure without seeing the actual setup though.

[madpogue]

The reverse lights shouldn't matter. If the tailgate light bar is wired to the parking light circuit it shouldn't matter either. But disconnect it just to be sure. The common culprit is the cab-roof center stop light. The turn signals also play a role, since the signals and brake lights use the same filaments in the back. Typical symptom is, center stop light burned out, you hit the turn signal, and the TC unlocks.

[Gootee]

Mine does this as well but no burned out bulbs. No added light bars, doesn't do it all the time but about 90% of it.