Ok. I have information.
While running errands earlier it did this three times. However today I noticed that while slowing down prior to the slip, i got a "clunk" similar to the driveshaft clunk, but heavier. Then I would get the slip between 1 and 2 when taking off from the stop.
After driving 15-20 min I checked the fluid. It comes to the bottom of "low" on the hot side of the stick. So it is a little low but it strikes me as odd I would have issues this severe with only a quart low. (Although i do need to find out what quantity the difference between high and low represents.)
As for the maintenance question, in September I did do a fluid exchange (via transmission cooler) with Valvoline Maxlife, and was incredibly meticulous about matching what came out with what went in, then checked it a few times over the next week and all was well. I've driven a few thousand miles since then and zero issues until the other day.
(I typed this part while waiting for something... now I'm home)
On the way home from part one of this message, it did this "slip" thing repeatedly, and I got a check engine light, along with the VSC/TRAC combo.
Here are the codes I got:
P0771 - Shift Solenoid E Performance or Stuck Off (confirmed)
P0771 - Shift Solenoid E Performance or Stuck Off (current)
C1201 - Engine Control System Malfunction (current)
(I understand this is simply a generic "something is wrong" code and not something directly related)
B2799 - Engine Immobilzer System (history)
(A while back I did try to start it with my "door only" metal emergency key so this might be that)
I'm going to do a little searching and see what I can find. Meanwhile... anyone dealt with this before?
One of the thoughts going through my head is "Did the solenoid just fail, or did something cause it to fail?"
I thought this was interesting... but odd that it's not mentioned anywhere on any forum so I'm going to bet it's not extremely accurate. SOMEONE would have seen this by now:
SOLVED: 03 Toyota 4runner 4wd 4.7l had codes p0771 , - Fixya
Hello.
Before you start looking at replacing solenoids, here is something that you need to know:
Toyota has a technical service bulletin regarding this issue.
Changing the solenoids will NOT rectify your situation. Replacing the ECU in the car is what you need to do. The logic/programming is the problem, not the solenoids.
The good news is this: The ECU is covered, under the factory warranty! It will be replaced for free, if your car has less than 80,000 miles on it.
If you have more miles than 80K, call the Toyota Customer Experience Center at 800-331-4331; an analyst may be able to help offset your costs; they do this quite frequently.
This should get you fixed up. Thanks for visiting FixYa!
Tomorrow when it's light out, I'm going to correct the the fluid level and see if that solves it. If not, move on to more serious ideas...