So a quick recap I replaced my band anchor for 2nd gear about a month ago. Trans shifted fin afterwards.
Today I'm driving and the truck starts reving to 2.5 and won't pass 40mph even if RPms increase. I didn't think much of it was in traffic pretty bad. Then after not being able to go above 40 I couldn't get above 25 reving 2.5+ So I pulled into a gas station pulled the dipstick it checked out and I checked the driveshaft for damage. All good. I put it in park when I stopped and it shifted all the gears. Back on the highway it shifted fine. Worked fine for another 2 hrs. Then on my way home it did it again so at a light I shifted to park and back to drive and back to normal. Im thinking something is clogging the valve body any ideas?
Thanks.

 

If I was in your shoes I'd be looking at the governor pressure solenoid/sensor. Unplug the main wires going in to the case (can't think of the proper name) there won't be any automatic function after you unplug that tho. So now you can see if it's an actual hardware problem clutch packs bands etc by physically shift into 1 then rolling into 2 and finally 3. If you're having any issues with that...well I heard that the mega vipers are nice

 

So not sure what it's called but the cable that's on the transmission that is tightened onto a valve body part. The top one was loose has a spring to pull it back. I tightened that wondering if that could cause the issue. Other thing is if it's not. The gov. Solenoid conversion to gm style is that ok for a 4wd 46re since the product said fits all 2wd models nothing on 4wd thanks.

 

Re adjust the front band back it off 2 turns instead of 3. Then dig into the pan.

 

I ordered a new governor pressure solenoid going to do the conversion. New transducer as well. If anyone has some better ideas or if I am way off on the governor pressure solenoid lmk. Code being thrown is high voltage to O2 sensor which I hear the governor shares a ground with

 

I also replaced my heater core so the dash was pulled put an the ecm wondering if it might be electrical or what i ahould check thanks

 

Holding gears at large throttle openings is generally a sensor issue. Swapping out the governor pressure sensor/heavy duty solenoid *should* take care of it.