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:

• 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.

 

 

I think that's exactly what he said. I know it started with an 'e'

 

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.

 

 

 

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.

 

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.

 

Glad you found one JBrady! I'm assuming you're referring to this VERY long thread...?
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...

 

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.

 

Thank you bradland
Yes, that VERY long thread.
I agree that video is well worth watching.

 

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.

 

How did you come across this fix? I wish I would have seen this when I was having the issue!

Has this lasted or do you have to frequently repeat the steps?

 

well i did it about a week ago and have probably driven the car 3 or 4 times since, perhaps 60 miles. It still feels good. How long it will last I don't know...that's why I'd really like to understand how this trans "learns" someone's driving style and adjusts, if in fact it really does that. I just don't know. For now it works fine.

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.