Hi,

'99 4Runner, 3.4, 4x4 automatic, 233k miles.

4Runner runs well, and has for the last year that i've owned it. Everything's been going along fine.

Starting about 2 months ago, as soon as i just hit a steady flat cruise (55-60mph), i would get a slight/short "shudder", and my rpm's would drop ~300-500rpm. This drop/shudder wasn't consistent, and i thought it was a random misfire. Without having a CEL illuminated, I changed the plugs and wires. it made no difference.

about 2 weeks later, I popped a P0773 code, which is the lockup solenoid in the transmission.

The fluid wasn't dirty-dirty, but it wasn't a nice bright pink. I dropped the pan, tested the solenoid, and it checked out with the correct ohms per the FSM (~13ohms, iirc, and it's supposed to be between 11-15). i also put 12v to it and heard it make a soft click. It seems like it passed both checks per the FSM. there didn't seem to be an abnormal amount of junk in the pan, and there wasn't a ton of stuff stuck to the magnets.

i installed a new filter, refilled, and it drove great for about a week, then the issue came back along with the CEL (p0773 again). i flushed the fluid yesterday to make sure everything was squeaky-clean, and took it for a test drive. intermittent shuddering is still there. reset the CEL, and it comes back about 20-30 miles later.

am i screwed? should i try to replace the lockup solenoid even though it spec'd out ok? time for a rebuild?

i'm not having any issues with the transmission slipping at all, and have never had an issues with strawberry milkshake or anything like that.