Thoughts on LS430 rough shifting and A761e transmission
03-07-19, 11:23 AM
#1
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Thoughts on LS430 rough shifting and A761e transmission
Hello, Clublexus,
I created this topic to see if our knowledgeable forum members could share their best knowledge as to what is behind LS430 rough shifting pattern within all gear ranges that may eventually happen in our cars. My car is not an exception and since my last transmission oil change I am currently observing this issue and looking forward to fix it. However, I have limited experience in repairing transmission and I hope this forum can provide me some help.
In 2004, LS430 engineers introduced new A761e transmission that was the first sixth speed transmission. It was designed to improve fuel efficiency, however, it seems that this transmission has been developing some sort of imperfect operational state which may even result in failure if not repaired on time.
1) Is it true that by resetting Transmission (ECT) memory data, the ECM starts brand new parameters correction procedure and ensures transmission operation is reset to factory defaults?
2) Do any Techstream cables except for Mongoose offer ability to fully clear ls430 ECT memory by actually writing Zero values in memory file in the microchip?
3) Is it true that resetting battery for more than 20 minutes does not (!) reset transmission data?
4) Do electronics companies remove and flash EEPROM chipset to modify the transmission work pattern?
4) Is it true that Transmission can gradually customize its operation to reflect the worsening of oil quality over time, however, CANNOT do the same for the fresh oil that has been introduced to the system?
5) Is it true that ECM over time corrects the operation of transmission solenoids and “starts making” mistakes with the delay of opening/closing that may directly cause rough shifting?
6) How does ECM or transmission module knows that the fresh oil is being introduced in the system?
7) What does SIA electronics and similar companies do to ECM to “fix” LS43 rough shifting?Any insights will be greatly appreciated! Please help me determine what is important to know about this problem. Thank you! 
I created this topic to see if our knowledgeable forum members could share their best knowledge as to what is behind LS430 rough shifting pattern within all gear ranges that may eventually happen in our cars. My car is not an exception and since my last transmission oil change I am currently observing this issue and looking forward to fix it. However, I have limited experience in repairing transmission and I hope this forum can provide me some help.
In 2004, LS430 engineers introduced new A761e transmission that was the first sixth speed transmission. It was designed to improve fuel efficiency, however, it seems that this transmission has been developing some sort of imperfect operational state which may even result in failure if not repaired on time.
1) Is it true that by resetting Transmission (ECT) memory data, the ECM starts brand new parameters correction procedure and ensures transmission operation is reset to factory defaults?
2) Do any Techstream cables except for Mongoose offer ability to fully clear ls430 ECT memory by actually writing Zero values in memory file in the microchip?
3) Is it true that resetting battery for more than 20 minutes does not (!) reset transmission data?
4) Do electronics companies remove and flash EEPROM chipset to modify the transmission work pattern?
4) Is it true that Transmission can gradually customize its operation to reflect the worsening of oil quality over time, however, CANNOT do the same for the fresh oil that has been introduced to the system?
5) Is it true that ECM over time corrects the operation of transmission solenoids and “starts making” mistakes with the delay of opening/closing that may directly cause rough shifting?
6) How does ECM or transmission module knows that the fresh oil is being introduced in the system?
7) What does SIA electronics and similar companies do to ECM to “fix” LS43 rough shifting?
03-07-19, 02:45 PM
#3
If you talk to many Lexus master techs they will tell you that the failure rate on these transmissions is almost zero. So low, in fact that when I brought my car to the dealer for a harsh shift condition he refused to even entertain the idea that my transmission was bad.
My 05 is after the cutoff for the ECU reflash but still sometimes exhibits the harsh 2-1 downshift and harsh 5-6 upshift into OD. There are numerous stories online where people were in my exact shoes and sent out their ECM to SIA. When they got it back and installed it into their car it shifted perfectly. I’m trying it out now and I will update when I get it sent back to me.
The telltale sign for me is that when I disconnect my battery for a while and then hook it back up and run the car, the transmission shifts like I always wished it would. Slowly, the car “learns” the wrong parameters again and it goes back to its former shenanigans
My 05 is after the cutoff for the ECU reflash but still sometimes exhibits the harsh 2-1 downshift and harsh 5-6 upshift into OD. There are numerous stories online where people were in my exact shoes and sent out their ECM to SIA. When they got it back and installed it into their car it shifted perfectly. I’m trying it out now and I will update when I get it sent back to me.
The telltale sign for me is that when I disconnect my battery for a while and then hook it back up and run the car, the transmission shifts like I always wished it would. Slowly, the car “learns” the wrong parameters again and it goes back to its former shenanigans
The following 2 users liked this post by Peacebay:
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Russjz (03-08-24)
03-07-19, 03:39 PM
#4
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03-07-19, 03:43 PM
#5
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Peacebay, thank you for your input. We are in the same boat - I also sent my ECM to SIA as a first potential solution to the issue. I should be getting it back in the middle of next week.
SIA mentioned to me that they receive a lot of complaints from specifically LS430 and GS430 car owners and they successfully repair their ECMs. However, they do not provide details on what is actually they are doing and what are the hardware issues with this module.
May I know if you were able to proceed with Techstream diagnostic on your ECT and if you saw any error codes?
SIA mentioned to me that they receive a lot of complaints from specifically LS430 and GS430 car owners and they successfully repair their ECMs. However, they do not provide details on what is actually they are doing and what are the hardware issues with this module.
May I know if you were able to proceed with Techstream diagnostic on your ECT and if you saw any error codes?
03-07-19, 04:10 PM
#6
What year is your car, and at approximately what miles did you have it checked out by the dealer?
03-07-19, 05:23 PM
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03-07-19, 06:09 PM
#8
Peacebay, thank you for your input. We are in the same boat - I also sent my ECM to SIA as a first potential solution to the issue. I should be getting it back in the middle of next week.
SIA mentioned to me that they receive a lot of complaints from specifically LS430 and GS430 car owners and they successfully repair their ECMs. However, they do not provide details on what is actually they are doing and what are the hardware issues with this module.
May I know if you were able to proceed with Techstream diagnostic on your ECT and if you saw any error codes?
SIA mentioned to me that they receive a lot of complaints from specifically LS430 and GS430 car owners and they successfully repair their ECMs. However, they do not provide details on what is actually they are doing and what are the hardware issues with this module.
May I know if you were able to proceed with Techstream diagnostic on your ECT and if you saw any error codes?
But the tech did hook up his techstream to my car so we could check for any codes and nothing came up. I let it go for a while, but while the car sits for the winter I figured it would finally be the perfect opportunity to send it out. 87k miles on my 05 fwiw
03-08-19, 04:29 AM
#9
Peacebay, thank you for your input. We are in the same boat - I also sent my ECM to SIA as a first potential solution to the issue. I should be getting it back in the middle of next week.
SIA mentioned to me that they receive a lot of complaints from specifically LS430 and GS430 car owners and they successfully repair their ECMs. However, they do not provide details on what is actually they are doing and what are the hardware issues with this module.
May I know if you were able to proceed with Techstream diagnostic on your ECT and if you saw any error codes?
SIA mentioned to me that they receive a lot of complaints from specifically LS430 and GS430 car owners and they successfully repair their ECMs. However, they do not provide details on what is actually they are doing and what are the hardware issues with this module.
May I know if you were able to proceed with Techstream diagnostic on your ECT and if you saw any error codes?
- it is probably true this company see a lot of complaints. But we have to look at it as a whole. Lets say they see 100 complaints (wow that is a lot), but how many LS and GS was produced? That is probably .0001% (I am just guessing here), which may not mean there is a problem.
- if one is in a business of fixing things, one is more likely to say one of these, or all: "yes there is a problem","yes there are a lot of them","yes we can fix it", and "no we arent saying how the sausage is made". Not a knock against this company at all, it is just the nature of the business which is understandable.
- no car is perfect including LS. There maybe a problem here, but I am not sure it impacts every car. I am sure there is at least one LS that is just a lemon and have all kind of problems, but that does not means the LS as a whole is not a reliable car.
- I am also not sure if it may eventually happen. I would imagine we should have seen a pattern here by now if that is the case. I am sure we have millions of miles among members here, with probably the majority of folks has over 100K, so pretty good sample size. Also these cars are sold worldwide, I wonder if we have heard this from folks from outside of US?
- I am curious if the car with these problems have had their transmission fluid replaced before (drain and refill, or flush), or at minimum, someone confirms that the transmission fluid level is not low.
Would you let us know how the transmission work after the fix?
03-08-19, 04:35 AM
#10
Also have the problem on newly purchased Ls with 138000. Have worked out most of the bugs in vehicle though transmission issue has continued. Did a drain and refill twice, but the saga goes on. After reset of ECU the shifts are good but slowly morphs back the harder shifts. I am very interested in the results of the SIA fix.
03-08-19, 04:40 AM
#11
Not trying to start a debate here, but imho:
- it is probably true this company see a lot of complaints. But we have to look at it as a whole. Lets say they see 100 complaints (wow that is a lot), but how many LS and GS was produced? That is probably .0001% (I am just guessing here), which may not mean there is a problem.
- if one is in a business of fixing things, one is more likely to say one of these, or all: "yes there is a problem","yes there are a lot of them","yes we can fix it", and "no we arent saying how the sausage is made". Not a knock against this company at all, it is just the nature of the business which is understandable.
- no car is perfect including LS. There maybe a problem here, but I am not sure it impacts every car. I am sure there is at least one LS that is just a lemon and have all kind of problems, but that does not means the LS as a whole is not a reliable car.
- I am also not sure if it may eventually happen. I would imagine we should have seen a pattern here by now if that is the case. I am sure we have millions of miles among members here, with probably the majority of folks has over 100K, so pretty good sample size. Also these cars are sold worldwide, I wonder if we have heard this from folks from outside of US?
- I am curious if the car with these problems have had their transmission fluid replaced before (drain and refill, or flush), or at minimum, someone confirms that the transmission fluid level is not low.
Would you let us know how the transmission work after the fix?
- it is probably true this company see a lot of complaints. But we have to look at it as a whole. Lets say they see 100 complaints (wow that is a lot), but how many LS and GS was produced? That is probably .0001% (I am just guessing here), which may not mean there is a problem.
- if one is in a business of fixing things, one is more likely to say one of these, or all: "yes there is a problem","yes there are a lot of them","yes we can fix it", and "no we arent saying how the sausage is made". Not a knock against this company at all, it is just the nature of the business which is understandable.
- no car is perfect including LS. There maybe a problem here, but I am not sure it impacts every car. I am sure there is at least one LS that is just a lemon and have all kind of problems, but that does not means the LS as a whole is not a reliable car.
- I am also not sure if it may eventually happen. I would imagine we should have seen a pattern here by now if that is the case. I am sure we have millions of miles among members here, with probably the majority of folks has over 100K, so pretty good sample size. Also these cars are sold worldwide, I wonder if we have heard this from folks from outside of US?
- I am curious if the car with these problems have had their transmission fluid replaced before (drain and refill, or flush), or at minimum, someone confirms that the transmission fluid level is not low.
Would you let us know how the transmission work after the fix?
The following users liked this post:
jcarlo123 (06-03-22)
03-08-19, 04:59 AM
#12
Peacebay, To save time and effort to reset ECM without battery disconnect. https://www.clublexus.com/forums/sc430-2nd-gen-2001-2010/529464-how-do-you-reset-the-ecu.html Post 5 from Harold does the trick.
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Peacebay (03-08-19)
03-08-19, 05:10 AM
#13
Another thoughts here, may not be related. I used to own 02 SC430 and have done this trans mod which require dropping the pan. Pretty sure I read someone did this with the A761e (I was not focused on researching A761e since my SC did not have A761e). I can say that it was worth to have it done on my SC. It improve how it shift, a bit quicker/firmer.
Full disclosure, I have thought about doing this to my LS, but I do not drive the LS as "enthusiastically" as driving the SC haha
https://www.clublexus.com/forums/per...ng-dial-5.html
Full disclosure, I have thought about doing this to my LS, but I do not drive the LS as "enthusiastically" as driving the SC haha
https://www.clublexus.com/forums/per...ng-dial-5.html
Last edited by BCT; 03-08-19 at 05:17 AM.
03-08-19, 01:57 PM
#14
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Not trying to start a debate here, but imho:
- it is probably true this company see a lot of complaints. But we have to look at it as a whole. Lets say they see 100 complaints (wow that is a lot), but how many LS and GS was produced? That is probably .0001% (I am just guessing here), which may not mean there is a problem.
- if one is in a business of fixing things, one is more likely to say one of these, or all: "yes there is a problem","yes there are a lot of them","yes we can fix it", and "no we arent saying how the sausage is made". Not a knock against this company at all, it is just the nature of the business which is understandable.
- no car is perfect including LS. There maybe a problem here, but I am not sure it impacts every car. I am sure there is at least one LS that is just a lemon and have all kind of problems, but that does not means the LS as a whole is not a reliable car.
- I am also not sure if it may eventually happen. I would imagine we should have seen a pattern here by now if that is the case. I am sure we have millions of miles among members here, with probably the majority of folks has over 100K, so pretty good sample size. Also these cars are sold worldwide, I wonder if we have heard this from folks from outside of US?
- I am curious if the car with these problems have had their transmission fluid replaced before (drain and refill, or flush), or at minimum, someone confirms that the transmission fluid level is not low.
Would you let us know how the transmission work after the fix?
- it is probably true this company see a lot of complaints. But we have to look at it as a whole. Lets say they see 100 complaints (wow that is a lot), but how many LS and GS was produced? That is probably .0001% (I am just guessing here), which may not mean there is a problem.
- if one is in a business of fixing things, one is more likely to say one of these, or all: "yes there is a problem","yes there are a lot of them","yes we can fix it", and "no we arent saying how the sausage is made". Not a knock against this company at all, it is just the nature of the business which is understandable.
- no car is perfect including LS. There maybe a problem here, but I am not sure it impacts every car. I am sure there is at least one LS that is just a lemon and have all kind of problems, but that does not means the LS as a whole is not a reliable car.
- I am also not sure if it may eventually happen. I would imagine we should have seen a pattern here by now if that is the case. I am sure we have millions of miles among members here, with probably the majority of folks has over 100K, so pretty good sample size. Also these cars are sold worldwide, I wonder if we have heard this from folks from outside of US?
- I am curious if the car with these problems have had their transmission fluid replaced before (drain and refill, or flush), or at minimum, someone confirms that the transmission fluid level is not low.
Would you let us know how the transmission work after the fix?
I will definitely share the results of the fix, hopefully they do some magic.
03-08-19, 02:12 PM
#15
just to add one more anecdote to my story — my car lived in Florida its whole life until last year. Definitely could be on to something