Thoughts on LS430 rough shifting and A761e transmission
#31
They also just finished mine up today as well... ours must have been in the same batch. Small world.
I asked to speak with one of their techs and they called me back within about an hour. I asked him to describe what issues they saw and what they do to repair these boards. These are his words paraphrased:
Keeping my fingers crossed! I will keep everyone updated as well.
I asked to speak with one of their techs and they called me back within about an hour. I asked him to describe what issues they saw and what they do to repair these boards. These are his words paraphrased:
- The transmission circuit is pretty large -- it comprises about 25% of the board
- They see 20-30 problematic Toyota boards per week
- The cold solders are the main culprit in these. They break down over time with the constant heat cycles.
- There's a small chip in this circuit (forgetting the name) that is mainly affected by these poor connections. The 2-1 harsh downshift is the most common symptom but there are many others.
- No matter what, the whole transmission circuit is redone. So they don't target specific issues (like the 2-1 downshift) and say "Oh, this solder must be bad." They just redo the whole thing
Keeping my fingers crossed! I will keep everyone updated as well.
The following 4 users liked this post by Peacebay:
#32
They also just finished mine up today as well... ours must have been in the same batch. Small world.
I asked to speak with one of their techs and they called me back within about an hour. I asked him to describe what issues they saw and what they do to repair these boards. These are his words paraphrased:
Keeping my fingers crossed! I will keep everyone updated as well.
I asked to speak with one of their techs and they called me back within about an hour. I asked him to describe what issues they saw and what they do to repair these boards. These are his words paraphrased:
- The transmission circuit is pretty large -- it comprises about 25% of the board
- They see 20-30 problematic Toyota boards per week
- The cold solders are the main culprit in these. They break down over time with the constant heat cycles.
- There's a small chip in this circuit (forgetting the name) that is mainly affected by these poor connections. The 2-1 harsh downshift is the most common symptom but there are many others.
- No matter what, the whole transmission circuit is redone. So they don't target specific issues (like the 2-1 downshift) and say "Oh, this solder must be bad." They just redo the whole thing
Keeping my fingers crossed! I will keep everyone updated as well.
The following users liked this post:
JBrady (03-13-19)
#33
The following users liked this post:
06GS300Lex (02-07-21)
#34
I was experiencing the rough shifting in my 2006 as well. I bought 9 quarts of Toyota WS, a new oem transmission filter, oem pan gasket, and replaced the solenoid involved in the rough downshift. The solenoid that fixed my problem happened to be the SLU(lock up solenoid). These 6 speed transmissions seem to have solenoids go bad, but after diagnosing and changing my car shifts perfectly now at 240,000 miles. I had dealt with the crappy shifts for about 7 months before taking this on myself. I did about 4 hours searching for parts, possible problems, ECU resets, and diagnostics for solenoid voltages. Once you drop the pan they are easy to remove and test. 3 of the 9 quarts I used doing a simple drain and fill, which did not fix the problem. I used another 3.5-4 to refill after dropping the pan, changing the filter and solenoid, and warming up the transmission fluid to the correct temperature to open the level plug. SC430 2006 up have same part #s for solenoids. IS350 shares the same part # for the SLU. A guy on ebay has an entire kit to replace all solenoids for the A761e for $299. PM me if you need help or diagrams. Oh yah, I also have Techstream.
The following 6 users liked this post by robbyboy32:
06GS300Lex (02-07-21),
JBrady (03-13-19),
Mfab15 (07-21-24),
MisterNino (02-14-22),
Peacebay (03-12-19),
and 1 others liked this post.
#35
#36
#37
Sure sounds like it, especially since we're both experiencing the harsh shifts only after the car "learns" the behavior after a reset. The tech was so sure about it too, like it was so routine to him he kind of takes it as a given now.
#38
Hey guys, old CL member here. Have a 99 LS400 and just picked up a 2004 LS430 CL B/B with 104k miles. LOVE the car but feel that transmission service (fluid change) is a good idea based on the very long thread. Found this thread wondering how many 6spds have failed since doing a fluid change and now I am wondering about the ECU and the solenoids. I did not see a link for the SIA Electronics so I searched and here it is for those wondering http://siaelec.com/product/lexus-ls4...repair-return/
I am definitely interested in the feedback as people get this done. So far I have not noticed any problems but would always rather service early than wait until it is too late.
I am definitely interested in the feedback as people get this done. So far I have not noticed any problems but would always rather service early than wait until it is too late.
#39
Hey guys, old CL member here. Have a 99 LS400 and just picked up a 2004 LS430 CL B/B with 104k miles. LOVE the car but feel that transmission service (fluid change) is a good idea based on the very long thread. Found this thread wondering how many 6spds have failed since doing a fluid change and now I am wondering about the ECU and the solenoids. I did not see a link for the SIA Electronics so I searched and here it is for those wondering http://siaelec.com/product/lexus-ls4...repair-return/
I am definitely interested in the feedback as people get this done. So far I have not noticed any problems but would always rather service early than wait until it is too late.
I am definitely interested in the feedback as people get this done. So far I have not noticed any problems but would always rather service early than wait until it is too late.
https://www.clublexus.com/forums/ls-...er-thread.html
I'm pretty sure this video is in that thread but if you skipped over it I highly recommend it-
It can be difficult to get the fluid level correct as most nonToyota/Lexus techs have no idea how critical it is. If I were in your shoes I would verify the fluid level first and foremost to rule out the possibility of that causing any issue...
Last edited by bradland; 03-13-19 at 10:49 PM.
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JBrady (03-13-19)
#40
I'd like to add that the OEM SLU solenoid I bought was revised by Toyota to replace the older, original part number. I think they realized there was a problem with failure (possibly due to "sealed" transmission?). I compared the new solenoid with the old, and they are, in fact, slightly different in design. For example the newer version has a small metal mesh filter and different shape ports. I verified that this was correct on lexuspartsnow. The problem is not just with our model, but also others like SC, IS, and RX. Transmission servicing is a basic concept, as are oil changes and other maintenance items. I could ramble on, but start with the simple and logical diagnosis and work your way up.
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MisterNino (02-14-22)
#42
My '05 has had somewhat rough 5-6 upshifts, seems like it hunts occasionally, and a yr ago had the violent 2-1 downshift problem. Saw somewhere on this board the following process to reset the trans:
a. insert key
b. turn key to on, no start
c. press gas pedal to floor
d. hold pedal to floor 5 seconds, key to off position, then release gas pedal
e. wait 2 minutes
f. remove key.
I tried it and was stunned at the improvement. Suddenly the trans shifts ultra smooth, no notchiness at all in any gear, the 2-1 downshift tug is gone. Quite surprised but very pleased.
As someone else commented I guess this means the trans adjusts itself over time based on driving behavior. If this is true, I'd really like to understand the logic of the adjustments...meaning, driving behavior xxxx results in specific adjustments yyyy. Would be very interesting to understand what Toyota engineered here.
a. insert key
b. turn key to on, no start
c. press gas pedal to floor
d. hold pedal to floor 5 seconds, key to off position, then release gas pedal
e. wait 2 minutes
f. remove key.
I tried it and was stunned at the improvement. Suddenly the trans shifts ultra smooth, no notchiness at all in any gear, the 2-1 downshift tug is gone. Quite surprised but very pleased.
As someone else commented I guess this means the trans adjusts itself over time based on driving behavior. If this is true, I'd really like to understand the logic of the adjustments...meaning, driving behavior xxxx results in specific adjustments yyyy. Would be very interesting to understand what Toyota engineered here.
#44
I searched a bit for the post that described the process and can't find it but it's somewhere on ClubLexus...as i recall, the post had just the steps and that was it.
#45
Update: I am receiving my ECM back tonight. I will put my car into testing for different acceleration scenarios, including using manual shifter. I will also attempt to clear ECM memory using the method suggested above, however, only if needed.
i know that the testing must be extended for at least one or two weeks for better statistics.
As far as I understand how “learning” works, adaptive parameters of driving patterns are being recorded in the memory dump file in microchip EEPROM which is independent to energy supply. Dealer Techstream May allow to clear the data by writing 0 in each cell, which is technically the way to fully reset ECM memory. Non-dealer Techstream does NOT clear ECM (ECT) memory even if it says so due to imperfect connection cable and pirated software.
After the learning takes place, EEPROM seems to fail to properly update further driving behavior due to “transmissions circuitry” problem adding to the general problem of rough shifting.
i know that the testing must be extended for at least one or two weeks for better statistics.
As far as I understand how “learning” works, adaptive parameters of driving patterns are being recorded in the memory dump file in microchip EEPROM which is independent to energy supply. Dealer Techstream May allow to clear the data by writing 0 in each cell, which is technically the way to fully reset ECM memory. Non-dealer Techstream does NOT clear ECM (ECT) memory even if it says so due to imperfect connection cable and pirated software.
After the learning takes place, EEPROM seems to fail to properly update further driving behavior due to “transmissions circuitry” problem adding to the general problem of rough shifting.