Toyota Repair: 1997 Toyota 4Runner -P0770 code After Trans Flush, 4runner sr5, toyota 4runner

Question
My 4Runner SR5 4wd aotomatic w/ 160k - well maintained - but has been doing some really strange things over the past few months.  I had driven about 45miles all hwy (avg 65mph) when exiting the highway at the end of the ramp there is a light - traffic was stopped for a few minutes & about 45-50sec after coming to a stop there was this jolt as if I had just been hit from behind... No one was behind me.  I looked this up and saw multiple posts re: 4cyl 4Runners doing this and needing to grease the drive shaft to fix it & that it was annoying but nothing harmful.  This only happened 5-6 times & then stopped & has not returned.  Then, same scenario, drove on highway about 30 miles avg 60mph - exit ramp ends at a stop sign, after stopping when I tried to accelerate there was NO POWER RPM's shooting up super high engine not "engaging" (my word) put their in neutral - said a prayer - put it back in drive and it finished the last 5miles of the trip -- the car sat for a few hours & made it home without an issue.

Took the truck into the shop told mechanic about both problems and told him that the engine gust seemed to be running "rough" and had just started making a knocking noise - he kept truck 5 days, told me engine looked good - no issues or problems at all that he could find -- but that the suspension was all messed up - needed shocks, ball joints, sway bar - and the like - he repaired all of these & did an oil change. Cost me almost all of the money I have, currently unemployed due to cancer...  

As soon as I picked the truck up - 10 miles into my trip home the oil light flickered, then came on, then went off -- I called mechanic, he said probably a sensor issue and not to worry - 2 days later after making the same 45 mile trip as described above, and again after stopping there was no power at all and truck merely drifted - now the engine light was on (first time ever) and it had to be towed back to mechanic.  He said it "threw a bunch of codes" and that he was going to flush the transmission.  He had truck 5 more days, flushed Trans & had a mechanic drive it appox 100miles - highway - stop - highway - stop & said truck should be ok - let's pray we don't have to replace the transmission, the though of that made me sick.  

Today is just 6 days after I picked the truck up from the Trans flush & the engine light came on, in my opinion it still sounds weird and isn't driving as it should... Today the check engine light came on - friends husband read codes P0770 --- (Selinoid E Code) -- I have no money and adter being worked on my truck is worse than it's ever been.  Please tell me what you think is wrong & how I should best handle this.  

Thank You
FC

Answer
I hate to have to tell you this but this code usually comes up when there is a pending transmission failure, the code sets in most cases because the lock up torque converter is failing causing metal particles to be distributed in the transmission oil, this usually results on this solenoid getting clogged up with particles. I think the mechanic knew this and hoped that this would clear up the problem, which it did for a while but now it's back.
Ask the mechanic to remove the transmission oil pan and inspect it for metal particles and clutch friction material in the oil in the oil pan.