While accelerating normally from a stop the transmission? shifts into 2nd with a heavy jerk. All other gears normal. It doesn't do this under hard acceleration or under very gentle and slow throttle application.
Is this a COP issue, a transmission issue or just a driving style thing?

Thanks. Randy.

 

do you fell any "missing" under acceleration? how many miles on your rig? also has the transmission ever been serviced?

 

It has 170,000 miles and I have had it for a month now. The 5.4 was replaced by a dealer with a new reman Jasper 5.4 about 50,000 miles ago. Don't know about a trans service. The only "missing/stumble" I have found happens while driving up a steep grade under load and then only very slight. So slight it could just as well be cheap gas as a COP going.

 

another possibility is you have a vacuum leak going on and it wouldn't hurt to service your trans.

 

A hard 1-2 "bang" shift is usually caused by a broken 1-2 accumulator spring.

This has nothing to do with vacuum (the transmission doesn't use vacuum) or a misfire (which would not show up as a harsh shift anyway).

 

I'll get some carb spray and mist around the vac lines and see. The trans I can maybe do too, have to look it up and see if it's in a reachable area or if the trans has to be dismantled. Thanks guys for the info, I really appreciate the help.
Randy.

 

There's nothing in any of your description that indicates that would be useful. In any event, spray and pray (or listen) doesn't work anyway, the computer is too fast.

The accumulator spring doesn't require tear-down, see service manual.

 

I researched some past threads from 2000 -2010 about the springs replacement and have ordered the kit. No brainer. I wont be spraying anything, that was a joke. Thanks again for the help.