LX450 Auto Transmission - weird behavior during short stop-and-go (1 Viewer)

[brownjeans]

The transmission in my '96 LX450 has some odd behavior. Here's the details:

• ATF fluid is spot on full
• No burnt smell or anything like that
• Occasionally (not all the time), when I come to a stop and that stop is going to be a short stop-and-go the engine revs as though the transmission disengaged for the stop, then before I can lift off the throttle the transmission slams into gear and I start moving.
• Shifts fine through all gears. No slippage while driving.

It's just that one scenario. To put the action into clutch and manual terms, it's like it pushes in the clutch for the stop, then wants to do a drop-the-clutch burnout off the line. I can't imagine this is good for the transmission. And it's also super bad if I'm trying to shoot a gap in traffic.

I can modulate the brake and throttle to keep the transmission engaged and prevent this behavior from happening.

Anyone know what's going on? Should I start saving money for a new transmission?

 

[simple]

I'm not an expert on ATF but it sounds to me like your torque converter is going bad.

 

[jonheld]

Could be as simple as a failing lock up solenoid. The A343F is an electronically controlled transmission and there is an entire section of the FSM for diagnostics.
I would start with that before throwing parts at it.