700R4 Shift Points Changed Overnight

[ZZ]

I drove my truck on a 160 mile round trip yesterday. I thought it did well, but my wife drove it this morning and the shift points for 1-2, 2-3 went up about four mph, and 3-4 stayed the same.

1-2 did shift around 11 or 12 mph, and it now shifts around 15. 2-3 did shift around 18 or 19 mph, but now shifts at 24 mph. 3-4 was shifting at 40 before this and it didn't change.

The only thing I can think might've caused this was that I forgot to turn on the manual locking TC switch on the return trip for about 5 miles. I was running 68 mph, but the tranny temp only got up to 174 degrees. It quickly cooled to 156 after I flipped the switch.

I wonder if I damaged the tranny or is it possible the TCC adjustment has slipped?

[DmaxMaverick]

When was the last fuel filter change, and has your fuel source been consistent? A plugged filter (or one beginning to plug) will require more pedal for the same power. The translation is higher shift points. I could always tell when a filter on my 6.2's was beginning to need changing when the shift points increased. It was also a pretty good indicator I got a load of lower quality fuel.

I'd suggest starting with the fuel thing. Also, measure the adjustment of your TV cable, both the adjuster end, and the exposed cable, and check that it is able to move easily. Make sure your TV cable mount is solid, and hasn't loosened or bent. Usually, a failed hard part will result in more than a 3-4 MPH change.

[ZZ]

Thanks, I never would've considered the fuel filter for this problem. I haven't changed it in about a year. It is still starting & running good, but I will change it tomorrow or over the weekend. The fuel came from the same place that I have been getting it. If the filter change doesn't help the shifting; then I will get into the shift cable.

[ZZ]

The fuel filter made no change.

It straightened itself up after a few days. It is shifting right on the money again. I talked to the tranny tech, and he thinks some rebuild break-in trash might've gotten hung in the throttle valve and then worked its way out. I drove it on a 200+ mile round trip the other day, and all is still well. Maybe it won't do this again.