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Occasional abrupt trans shift

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Old 04-07-17, 03:57 PM   #1
Bocatrip
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Default Occasional abrupt trans shift

For 7 years and now at 128,600 miles my car had always shifted flawlessly. The car has always been serviced at Lexus by the previous owner. The fluid is very clean (red) and does not smell burnt. I have never changed the fluid since my purchase and have put 30,000 miles on the car. I do pretty much 100% city driving and very occasionally go on the highway. Every now and then (probably when warming up) the car might have an abrubt shift going into an upper gear. Never has it happened dropping to a lower gear. Is there any resetting of the ECU that might help instead of changing the transmission fluid? Again, it does not happen very often and the trans does not slip. Thanks again for any feedback.
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Old 04-07-17, 04:29 PM   #2
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my car with the 6 speed transmission will not shift into overdrive until the temp reaches between the C and the 1st mark. I am usually going 75 mph before this point is reached and the shift into overdrive is noticeable to me. It was worse before I did a couple drain and fills 30,000 miles ago and is beginning to become more apparent now. I am wondering if the 5 speed also has this built in to its transmission. just wondering
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Old 04-07-17, 04:44 PM   #3
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If you have an 01-03, shifting should be invisible. With 04-06 shifting should be seamless. Besides the occasional abrupt upshift, does it generally shift smoothly? City driving (rather than freeway miles) generally means more wear and tear on the car.

Both my Lex mechanic (01 430) and tire shop guy (Honda) do drain& fills. With my 04 (at 102), the shifts were noticeable. I did 2 (drove 1k between each) and the car now shifts seamlessly.
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Old 04-07-17, 05:16 PM   #4
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[QUOTE=tallcaguy;9828554]If you have an 01-03, shifting should be invisible. With 04-06 shifting should be seamless. Besides the occasional abrupt upshift, does it generally shift smoothly? City driving (rather than freeway miles) generally means more wear and tear on the car.

Both my Lex mechanic (01 430) and tire shop guy (Honda) do drain& fills. With my 04 (at 102), the shifts were noticeable. I did 2 (drove 1k between each) and the car now shifts seamlessly.[/QUOTE)

I would say that the majority of the time my car shifts like butter and I don't even notice the shifts. It generally is noticeable when warming up and driving very slowly. I was just thinking that I do so much city driving that a possible ECU reset (if there is even such an option) might help. Not thinking of doing a drain and refill at this time. I checked my fluid level numerous times today and it is just about on the full mark after driving 30 minutes. Fluid level and condition of fluid is not an issue.
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Old 04-07-17, 06:59 PM   #5
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Quote:
Originally Posted by JffGRY706 View Post
my car with the 6 speed transmission will not shift into overdrive until the temp reaches between the C and the 1st mark. I am usually going 75 mph before this point is reached and the shift into overdrive is noticeable to me. It was worse before I did a couple drain and fills 30,000 miles ago and is beginning to become more apparent now. I am wondering if the 5 speed also has this built in to its transmission. just wondering
It does actually. My car (01) doesn't fully lockup / shift into overdrive (idk which one) until the temp needle hits the first mark above C. It's not very noticeable, but I try to drive slower (50-55 mph) until it locks up and the smoothness might be a function of speed. I've always meant to pull out my ODB reader and figure out what the temperature threshold is, my suspicion is that the transmission locks up at the same time the thermostat opens.

When warm, my car sometimes shifts abruptly into 5th gear if I'm going downhill at ~40 mph and have a very light or no throttle opening.
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Old 04-08-17, 11:00 AM   #6
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[QUOTE=Bocatrip;9828575]
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Originally Posted by tallcaguy View Post
If you have an 01-03, shifting should be invisible. With 04-06 shifting should be seamless. Besides the occasional abrupt upshift, does it generally shift smoothly? City driving (rather than freeway miles) generally means more wear and tear on the car.

Both my Lex mechanic (01 430) and tire shop guy (Honda) do drain& fills. With my 04 (at 102), the shifts were noticeable. I did 2 (drove 1k between each) and the car now shifts seamlessly.[/QUOTE)

I would say that the majority of the time my car shifts like butter and I don't even notice the shifts. It generally is noticeable when warming up and driving very slowly. I was just thinking that I do so much city driving that a possible ECU reset (if there is even such an option) might help. Not thinking of doing a drain and refill at this time. I checked my fluid level numerous times today and it is just about on the full mark after driving 30 minutes. Fluid level and condition of fluid is not an issue.
Per Airchomper, sounds like it's a warm up issue. Doesn't sound like you have anything to worry about.
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Old 04-08-17, 04:34 PM   #7
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There is a commonly discussed lurching shift at low speeds as the car glides into a slow turn then you put your foot on the pedal to slowly accelerate it will rev then shift. I had the software update at Lexus Dealer done to resolve this issue.
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