lsdude

I live in Sunny Florida. When we had cooler weather the past few days (less than 73 degrees F), I noticed the car shifting smoothly. When the temperature went back up to 77 today, I noticed the car shifting harder. I'll say the shifting problem has been going on for awhile, but today is the first time I think I've narrowed it down to the ambient temperature. I also noticed it shifting smoother when I recently replaced the MAF sensor, but that lasted a few hundred miles. The fluid has been changed twice by the local Lexus dealer. Throttle body has been cleaned. Air filter was replaced a few months ago.

Does anyone have any ideas? It's an 06 and shouldn't be affected by the 04-05 transmission TSB.

TIA.

Lavrishevo

iTrader: (1)

You may be low on transmission fluid. It's easy to get it wrong. Take it back to the dealer and have them verify it at operating temp. Hard shifting is usually related to an under filled transmission.

lsdude

I took it back after the second fluid swap. They told me they looked at it, spent hours, had their master tech analyze it and didn't see anything wrong. It did feel a little better after replacing MAF sensor but not butter smooth. Maybe I should drain and fill myself to make sure it's done right.

The original reason why I changed the fluid was the transmission shifting issue (hoping it was the fluid). But that didn't help the situation. This car was owned by an elderly woman who went to a nursing home.

Lavrishevo

iTrader: (1)

Is the hard shift when accelerating, down shifting, or both? I know it sounds odd but you may want to replace your engine temp sensor. If its malfunctioning it can cause weird things to happen and you will not get an engine check light.

lsdude

Only when accelerating. Thanks for the suggestion. Before I start swapping parts, I'll wait to see if anyone else has suggestions too.

lexman52

I would not think that the MAF or throttle body would have any thing to do with the shifting of the transmission ?

lsdude

Probably not. My perception of the MAF improving the shifting may be from resetting the ECU every time I swapped a part.

rkw77080

Please take a look at the attached Symptoms Table and try to narrow the problem. MAF does not seem to be a cause of your harsh-engagement problem.

lsdude

Thanks for everyone's input. After also realizing that shifting from 5th to 6th was not smooth, I went ahead and replaced the engine temp sensor. What a difference! The car shifts much smoother and is enjoyable again. I also cleaned the idle port which may have helped. Thanks again for everyone's help. This forum is an invaluable tool with great folks!