This morning I was coming to work, and for no reason my tranny slammed out of OD. I immediately let off the gas and it slammed back into OD. I then manually turned the OD off and back on, and it really seemed to shift hard. What caused this? and is it a sign of bigger problems?

A little more info:
The truck was relatively warm, it was about 3 or 4 miles from the house. The road was flat, and it was under steady cruising throttle around 60 MPH.

It only did it the one time, and every other shift seemed as smooth as always.

Oh, it's a Y2K 5.4L ORP.

 

36,

Did you by chance accidentally hit the brake pedal? If the brake pedal is tapped during cruising, the t/c will unlock and the cruise will drop out, that wasn't it was it?

Just trying to think of something, sure doesn't sound normal that's for sure.

~DM~

 

No, I didn't tap the brake. I was cruising w/ steady pressure on the gas - I didn't have the cruise on. I was just cruising at a steady speed w/ constant pressure on the gas. It was more than the torque converting unlocking, it slammed out of OD, and then when I let off the gas it slammed back into OD.

 

36,

I guess if the TPS had sent a WOT signal to the EEC, then the tranny could've interpreted it as pedal to the floor and downshifted, then when you let off the gas, the TPS sent the correct throttle position value and then the tranny was instructed to go back into OD, my 2 cents. Have the TPS checked, it might be worn out...

Hope you find the problem though. Also, if it was an electronic fault, the EEC should've logged an event for a technician to find.

~DM~

 

It would figure, my truck just went out of warranty about a month ago!
It hasn't done anything of the sort since then, so I'm hoping it was a one time freak occurence that will never happen again.