2000 Chevy Silverado - Late/No shifts & Whiny 4WD

[Fraterado1855]

I'll preface this post by saying that I have still not been able to identify a way to start my own build thread, so as to have all of my truck whoas contained in a succinct package. If there is a way to do this, or I have posted incorrectly, please advise (sorry Mods, #newbie)

My 2000 Chevy Silverado 5.3L Z71 w/4L60E transmission and approximately 160K miles has started to provide me with some challenges; though no trouble codes are currently being thrown, and there is no check engine light. (Recently through a P0300 - Random Misfire, but I do not think it's related; tell me if you think otherwise).

The truck will not shift from 1st to 2nd while under heavy load. It shifts very late, and maintains high RPMs regardless of % throttle applied. If I let of the gas a bit around 4-5K RPM, it then shifts in to 2nd gear. This is repeated during highway driving while trying to shift up from a cruising speed. 65 and below, it sits with high RPM; around 3500, 4000 - which is much higher than I remember and is killing my gas mileage.

The first time this happened, I decided to flush the transmission fluid for the first time, though I did not include the full 11 qts w/torque converter. I was hoping something simple would fix the problem, but I regress. The major thing that made this job a massive PITA was the stupid gear selector bracket on the driver's side of the transmission drain pan (deep). I could not get it out of the way, and getting to the top where the 6 point bolt heads are (of course rusted) was impossible for me. Deep in to the evening with little light and transmission fluid dumping all over me, I ended up letting out a few thunderous man grunts and profane statements to get it out. It was fine to put back on, which puzzled me more. If there is a DIY for this action, please let me know. I also have not found a lot of information with how to also flush the torque converter, and I'd like to know how involved that job is too.

I spend most of my time in 2WD as well, with very light towing (helping friends move, a motorcycle, etc) but some limited 4WD driving for snow. I am used to hearing a little bit of whine in 4WD especially at low speeds, but have recently thrown a "service 4WD" light a few times. I am hoping that a fluid change here will allow me to move forward.

I have a bunch of Valvoline extended life DEX/MERC transmission fluid, Lucas Oil 75W-90 transmission/differential fluid, a pump bottle, and a week to get these problems addressed before my spring break is over. I also got a new 1-2 shift solenoid, though I am not sure if I need it.

I am not about to call it a day, liquidate the truck for $5-6K and take out a big loan on something new. Any help/resources/input you can provide is great appreciated. Please see my other posts for other problems, some of which will be a much more involved job I am sure. For now, I'll have my nose in my Haynes and these forums.

Thanks

- - - Updated - - -

(Sorry for the bump, not attempting to be a self-promotion)

I just found my older original thread on this topic that I was not able to find:
http://www.gmtruckclub.com/forum/sho...nge-Gone-Wrong

To answer those questions:

1. There were no metal shavings or obvious debris in the transmission pan, it was just dirty.
2. The filter itself did not look that bad either.
3. I knocked the cap off of what I believe is the 1-2 transmission solenoid, but put it back on before the pan and it seemed fine. (I bought a new one just in case)
4. It went back on fine.

[Fraterado1855]

May have found the issue.

Trouble Code: P0751 - Shift Solenoid A Stuck Off

Will return with results after replacement.