dveneman

Hello!

If there are differences, would I be able to swap parts from my existing 1998 transmission easily?
Or would the only differences be with "computer signals" for shifting only?
Thank you for any information, since I may have a line on a "low mileage" unit to replace my tired A650e gearbox.

Yamae

https://www.clublexus.com/forums/ls-...nsmission.html
https://www.clublexus.com/forums/ls-...nto-ls400.html

dveneman

Thank you for directing me to these! I had seen the first discussion when I did a search. But there seemed to be some speculation so I wasn't sure .
Now the second link is pretty amazing. Makes me want to do the engine and trans. Nice work Yoda!
So I think I will go ahead and move on that '01 transmission. Will try to post something about my luck with it when finished .

dveneman

Follow up on some small differences (easily remedied) I found when installing a 2001 LS430 transmission into a '98 LS400 :
Pan dipstick tube routing , shifter selector rotary switch and some wiring harness supports.

My old transmission was working fine but developed a whistling noise and I noted fine metal "mud" in the oil. I found a CL seller parting out a 2001 LS430 with 150k that looked to be well cared for.
The exchange went well and everything seems to work just fine so far. The biggest thing was the dipstick tube. I swapped the pans ( I used my original) and installed a new filter. The shifter rotary switch mentioned above was easily exchanged from the old transmission.
I noticed shifter linkage and venting differences that did not effect the exchange . It looked like Lexus was trying to simplify the 430 a bit. I used the 430 torque converter as well.
The car started and upshifted well right away with no codes. The only thing I noticed initially was a sharp 2-1 downshift jolt. But this soon smoothed out. How a 1998 TCM can do that amazes me.
So for about $350 for the replacement and $100 in materials , the noise is gone and the car lives on.

Yamae

Thanks for the update and congratulations on your success although there were some issues. Your report would be helping others who need to do something similar.

dveneman

Follow up from using an '01 LS430 transmission in a '98 LS400.
The occasional 2-1 hard shifting would not go away. 90% of the time the shifting of all gears was fine. But when slowly wheeling around or in traffic jams, especially with the AC on , the 2-1 jolt could be bad!
So i decided to try installing the valve body from my original '98 transmission. That did the trick. Things are back to being very smooth. I cant even feel the downshifts now.

400fanboy

Interesting how you mention the 2-1 downshift. Take a look at this thread I wrote with the help of Yamae.

https://www.clublexus.com/forums/ls-...ttle-body.html

Though your solution was involving hardware changes on the transmission. Still curious how they seem to overlap in terms of symptoms.

dveneman

Toyota may have made some changes to ECU/valve body solenoid timing or pressure control when designing the 430. I just reinstalled my old valve body to match it's original ECU.

But I read your thread regarding the right and left passages which I have never cleaned . Thank you for sharing that. I have only ever cleaned the throttle body and the 4 tiny holes and was not aware of the other R & L passages.