Quick question for the group:

Will driving the car with the 2-1 downshift issue hurt the transmission? Or.... How far can I drive it?
The car is stuck in one city and I am 125 miles away. I need to get it here so I can get to the ECU.

Thanks!

 

I think it will. What I did was put the car in neutral while slowing down to prevent the hard shifting. Might help prevent damage.

 

yes it would but if you have no choice then you have no choice. I drove it for a few days like that then drove it from Lakeland to Orlando to get it fixed so that was like an 1hr drive. Car came back after getting the ecu fixed and transmission was fine but I heard you have to change out the fluids after

 

When I had the issue, I was told that shifting into neutral as you slow down to avoid the rough downshift was fine and did not damage the transmission. That said, the tech who told me that said to get it fixed promptly and not to use that method for an extended period of time. Also, a drain and fill now and a couple of times in the next six months depending on your driving habitsis a good idea and can only help rather than hurt the transmission.

 

Hello,
In the words of my grandfather, "This information ain't nothing but the truth." I am so thankful for the knowledgeable folks who help to keep Lexus owners on the road. I followed this lead. I received my ECU today from SIA Electronics. I couldn't be happier with their service. Lexie Pooh is shifting like normal. My downspeeds were atrocious. I believe this repair removed my Check Engine, VSC, & Trac Off Lights. The transmission Curcuit Clean-up was needed, okur. I feel like a kid in a candy store. I am so grateful. Thank you all a billion times over. Enjoy the holiday season. #keepupthegoodwork. #clublexusrock

 

+1 to the SIA solution working for me

 

We are now performing this 2004-2005 LS430 ECU rough shifting / downshifting repair. We also include complimentary ECU software updating in conjunction with our on-board repairs.

If you purchased a used ECU we also have the ability to write your VIN to the ECU to eliminate the P0630 VIN mismatch.

https://taninautoelectronix.com/prod...ough-shifting/

 

I had the same issue, 3rd to 2nd, 2nd to 1st. Common problem with the 3rd gen LS. ECU has a bad eprom. Josh at Relentless Autosports near Dallas repaired mine. So far 1yr and 12k miles later, no issues.

 

I have an 04 , no issues as of yet w/131,000 on the odo. Would it be wise to perform this fix preventatively or wait till i actually experience the issue. I've already had to send out my mark Levinson amp for what sounds like a similar issue with soldering?

 

This page gives you a good hint to fix the hard down shift issue just using a soldering iron and a good magnifier with almost no cost.
https://www.clublexus.com/forums/gs-...l#post11771920