i,m helping out a friend who had his 47re just rebuilt by a trans tech at home. he r&r the trans and brought it to the trans techs home. trannys in, 1-2-3 shift is fine, no lock up in 3rd, then trans shuttles between 3rd and 4th several times before finally going into 4th,then lockup. if o/d is off, the tranny shifts fine,1-2-3rd then 3rd lockup. truck has new rear diff speed sensor, tps has been swapped with known good one. the guy who rebuilt the tranny has swapped the valve body and its still the same, anyone know where i should start. seems electrical to me. gov actual and targets are in spec, sensors also swapped.

 

What year is the truck?
It could be APPS.
What codes come up?

 

tps already swapped, truck is 97

 

Could be the OD solenoid acting up. Put a scanner on the truck and see what the pcm is commanding.

Richard

 

o/d solenoid has been changed with sensor and v/b. if you look at pcm data the 3-4 solenoid is being shuttled on/off by the computer till it finally does apply fourth after 3-4 tries. also ther is no command for 3rd lock-up unless o/d off button is pressed. poss pcm internal issue, cleaned all engine and body grounds, added ground to pcm from battery, graphed tps, speed, trans temp,all clean with no distortion. no faults, good gov pressures, 90-95 psi in lock-up o/d.

 

I'd check the wiring for issues... if you're getting a bad connection anywhere it's going to mess with your head. You'll think you have it knacked and then it starts acting up again. It's the problem with computerized trucks... when they get old, the wiring causes all kinds of problems.

 

Was this a problem before or after the transmission was done? What VB was used or shift kit?