66RFE strange shifts, anybody experienced these symptoms?

[ScubaSteve178]

The solenoid pack TSB/recall/whatever had to do with shift issues caused by a loose pinout in the connector of the solenoid pack. The issue usually causes a check engine light to pop up, and has some pretty obvious shift/drivability issues associated to the tune of limited speed and gear selection. Generally speaking, pretty clear whether or not its the solenoid TSB issue or if its a valve body problem.

 

[seanclark1503]

I just got over a similar situation with 68rfe. Mine was down shifting so hard it was like the brakes were locked up. I thought my shifter cable wasn’t calibrated, that wasn’t the problem. The shifter (block) solenoid was going out. My tuner scanner code was ‘transmission range sensor malfunction’ . No parts place including dealership knew which part I was looking for. It took me a few days to determine the proper name of the the shifter block solenoid so I could get it. You valve body is probably not the problem, it’s the thing that controls it that’s about to die and put you in 4th gear only (limp mode).

 

[ScubaSteve178]

I just got over a similar situation with 68rfe. Mine was down shifting so hard it was like the brakes were locked up. I thought my shifter cable wasn’t calibrated, that wasn’t the problem. The shifter (block) solenoid was going out. My tuner scanner code was ‘transmission range sensor malfunction’ . No parts place including dealership knew which part I was looking for. It took me a few days to determine the proper name of the the shifter block solenoid so I could get it. You valve body is probably not the problem, it’s the thing that controls it that’s about to die and put you in 4th gear only (limp mode).

Problems with the solenoid pack usually result in a check engine code. Limp mode goes into effect any time the PCM acknowledges irregular parameters coming from the sensors in the transmission and can be a myriad of things. The solenoid pack is not known to be a regular problem aside from a known recalled defect that has something to do with shorting pins in the connector. Not saying it can't be a part of OP's problems, but generally speaking, solenoid packs don't go bad compared to the valve body itself, which is known to have issues with cross leaks and excessive seepage beyond the accumulator pistons resulting in irregular shifts and dragging clutches, as a result of poor castings and machining quality.