99 ES 300 auto to manual transmission

[lexus_007]

I've a 99 Lexus ES 300 that has an automatic transmission. I would like to convert it to manual shift - i.e. use the existing auto transmission, but shift it manually, by switching on/off the solenoids. I am new to working on transmissions, so please advise if it is possible. I got to know that Solenoid 1 and 2 are switched on/off when gears are changed. eg: 1st gear Solenoid 1 is ON and solenoid 2 is OFF, for O/D both are OFF etc. However, my car has 5 solenoids - SL1, SL2, SLT, DSL and S4 (I'll try to attach the diagram here). Is Solenoid 1 and 2 the same as SL1 and SL2? Will I need to control the other solenoids if I have to shift manually? Should I take care of anything else?

[gbhrps]

lexus_007,

 

You have an 18 year old car, this is your first post on this forum, you're wanting to dig into the electronics of the automatic transmission to over ride its Control Module, and you readily admit that you don't know what you're doing, and you're asking for someone to suggest how to proceed?

Okay, I'll answer your question. Don't do it, leave it alone. Do your shifting with the shift lever if you must, but don't screw around with a good thing. And here's why:

An 18 year old car suggests that it has a lot of miles already on the transmission, and the older they get, the less capable they are of accepting abuse. And if you're going to be shifting it yourself, rather than letting the computer make the decisions, then I will lay money down that you will abuse the transmission, which equals .... you'll soon be walking rather than driving this car.

An 18 year old car suggests that this is your first car perhaps, and that you also don't have the money to be making big repairs, otherwise why wouldn't you be driving a much newer vehicle? If you fry the electronics in this tranny, it isn't going to be a cheap fix.

If its not your daily driver, and its just a toy, the stakes are a whole lot different, but I, personally, wouldn't do it.

I've been wrenching on cars for over 50 years, and I wouldn't even begin to suggest that what you're trying to do is a wise move. If you want a car to shift gears with, get a car with an automatic with paddle shifters, or a stick shift, both of which are purposefully designed for what you want to do. But then again, its your car and your money. Do what you want.

[lexus_007]

Thanks for your advice! You have good deduction skills like Sherlock Holmes! :-)

BTW, the car doesn't run now, so I wouldn't make it any worse!

[gbhrps]

lexus_007,

Then that does change the game plan if its just a toy to play with.

In that case, I'd be making friends with a tech guy from a transmission shop and pick his brains for what you want to do. If you can find a professional tranny guy willing to share some of his time, you'll be a whole lot further ahead. Then again, you may learn that it would be a waste of time.

Trying to find the kind of info you need is not going to be possible on this forum. I've followed it for years and there just aren't that many wrenchers who are owners of Lexus vehicles. It could be the cache of the vehicle's reputation as a luxury vehicle, and draws on owners who are more willing to let someone else do the repairs by opening up their wallet. Now, the diesel truck forums, Corvette forums, antique car forums ... those people are almost always wrenchers, and have a high knowledge base of trannies, etc. Not so much Lexus.

You might try the Camry Forum (basically  the poorer sister of the ES300), has the same tranny, and maybe someone over there in another forum could be of some help. Good Luck in your search !

[lexus_007]

hmmm.... I never thought of that! I'll try it. Thank you gbhrps!