Transmission thud when shifting 2-3
01-16-17, 11:50 AM
#1
Driver
Thread Starter
Transmission thud when shifting 2-3
Hello everyone,
My 105k km 2007 IS 250 AWD has been making a thud sound when shifting from 2-3. The sound is ever so slight and you miss when going over the smallest bump. The thud sound does not come if the transmission shift from 2-3 before or by 25 kmph. Then, it is perfectly smooth. If the car shifts from 2-3 at speeds higher than 25 kmph the thud sound comes back (which is 99% normal driving). I have been doing a TON of research on what it could be and found the best theories below
not from club lexus forums)
1. "The thump you hear is the clutch friction disc coming to a sudden stop when you shift into first gear." by fretburnr
2. "Try waiting a moment after stepping on the clutch before engaging a gear, and engaging it a little slower/smoother. Sometimes the input shaft is still spinning and you'll hear a noise as your dog teeth engage a gear. Other times, those dog teeth aren't lined up perfectly and you get a little thunk as the dogs align with the spots on the gears" by fretburnr
The sound comes from the middle/rear part of the car. Is it my tranny going out or something else at fault? are the shift points not in sync?
When you put the car in manual mode, you no longer get the thud. But instead, after shifting from 2-3, 1-2 seconds later you feel a EXTREMELY slight slippage. WHATS GOING ON!! All other shifts are smooth beside 2-3.
My 105k km 2007 IS 250 AWD has been making a thud sound when shifting from 2-3. The sound is ever so slight and you miss when going over the smallest bump. The thud sound does not come if the transmission shift from 2-3 before or by 25 kmph. Then, it is perfectly smooth. If the car shifts from 2-3 at speeds higher than 25 kmph the thud sound comes back (which is 99% normal driving). I have been doing a TON of research on what it could be and found the best theories below
not from club lexus forums)1. "The thump you hear is the clutch friction disc coming to a sudden stop when you shift into first gear." by fretburnr
2. "Try waiting a moment after stepping on the clutch before engaging a gear, and engaging it a little slower/smoother. Sometimes the input shaft is still spinning and you'll hear a noise as your dog teeth engage a gear. Other times, those dog teeth aren't lined up perfectly and you get a little thunk as the dogs align with the spots on the gears" by fretburnr
The sound comes from the middle/rear part of the car. Is it my tranny going out or something else at fault? are the shift points not in sync?
When you put the car in manual mode, you no longer get the thud. But instead, after shifting from 2-3, 1-2 seconds later you feel a EXTREMELY slight slippage. WHATS GOING ON!! All other shifts are smooth beside 2-3.
01-16-17, 03:56 PM
#2
Find someone with a scanner that can look at the Transmission and see if there are any codes? I'm not sure they would show up with a CEL if your having trouble with a solenoid or something.
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