Modding the A340LE transmission

[2JZR31]

I am trying to do the DIY shift kit in my A340LE Aristo trans as done in this thread. http://www.supraforums.com/forum/sho...d.php?t=267655

The idea is to put shims under the accumulators. You can see the 2 in the top right corner are lifted out. I put 20mm of shims under there (this is on my spare trans) The shim can be anything. You can use a nut of the desired thickness. Check the link out for more details if you are interested (Muz I would look into this before you put the trans in as its a lot easier when its not upside down as shit falls out when you take the valve body off) People have experimented with various thickness shims and 20mm seems to be a good compromise between shift times and back jarring on gear changes.

However this is usually done with the A340 as found on the 1UZ and 1JZ it is not fully electronic and has a cable and a dial which can be turned up for more pressure. Solenoids control everything in the A340LE the E standing for "Electronic".

I found one thingo I could turn which closes an orifice in the valve body. Hmm wonder if closing it up would give more line pressure? Apparently the shimming alone will make the shifts way firmer but it would be good to know what else can be done in there.

[2JZR31]

OK I found the wiring for the solenoids. Does anyone know what each one does?

No1
No2
SLN
SLU
SLT

The 2JZ GE only has No1, No2 & SLN (I assume this is the same as the 1JZ and 1UZ trans) So SLU & SLT are the extra solenoids that the 2JZGTE trans has.

What do all these solenoids do?

[wiso]

if you want your shifts to be firmer and since you already have the valve body out you would probably be better sending it away to MV autos's and getting the modification done, thats how i did mine, it costed $330 all up, and they include the new stiffer springs in there for you to replace the ones unde the acumulators.

somehow i doubt this DIY mod would be as good as the real thing, i took mine for a drive, MV's says it shifts in .5sec now instead of 2 secs. and well to say the least, when you floor it its incredible, you don't even notice is shifted gears its soo damn quick, but it does give a solid kick

[wiso]

However this is usually done with the A340 as found on the 1UZ and 1JZ it is not fully electronic and has a cable and a dial which can be turned up for more pressure. Solenoids control everything in the A340LE the E standing for "Electronic".

well actually, the the A340 on the 1UZ and 1JZ is not totallty correct. the 1JZ soarer has an A340LE also, the 1UZ soarer has a A341LE. the solonoids still control everything

they each have differant valve bodies but i have found they are interchangable


the amount of people who mis-quote the model of the transmission is very annoying, wheather people do it because they are lazy, or they just don't know, but every body seems to generalise the "A340"

[cambelt]

A340 LE only means the general model and thats all . there are 30 different A340 maybe more . the 1 and 2 solonoids are the 1st to 4th shift the 3rd solonoid is lock up 4th solonoid is shift timing and the 5th is line pressure control . im not sure which is which (the 3 at the front of the box)

Dave

[2JZR31]

It has me stuffed on all the different versions of a A340. All I know is that mine is from an Aristo and has 5 solenoids and the DIY shift kit works great for the guys that have done it. The DIY shift kit is for has 3 solenoids. I think the 1UZ may have 4 solenoids? Or does it have 5 too? (check out pic)



I know that the A340's with less solenoids do not have as much electronic control as line pressure is controlled by a cable and can be increased with a dial on the valve bocy. The DIY shift kit works pretty much the same on all of the A340's. The shims do the same thing as uprated springs by compressing the springs and giving them more tension. But since my trans does not have any obvious way of increasing line pressure the shifts have not gotten much firmer, but they have gotten faster. I have to figure out which solenoids control the pressures and go from there.

I would rather experiment with this myself than just pay for an upgraded valve body. Where would the fun be in that? I have a spare trans

[EldarO]

if you want your shifts to be firmer and since you already have the valve body out you would probably be better sending it away to MV autos's and getting the modification done, thats how i did mine, it costed $330 all up, and they include the new stiffer springs in there for you to replace the ones unde the acumulators.

somehow i doubt this DIY mod would be as good as the real thing, i took mine for a drive, MV's says it shifts in .5sec now instead of 2 secs. and well to say the least, when you floor it its incredible, you don't even notice is shifted gears its soo damn quick, but it does give a solid kick

im wondering if this mod ends up killing your gearbox in some way.

nothing is free.

Eldar.O.

[wiso]

from what i know of a proper shift kit mod they modify the valves, boring out and fitted larger ones to make it flow more fliud faster, hence this actually extends the boxes life and there is less blockage and is much more efficient

its not usually springs under the accumulator i thought that made the box shift quicker, that just makes it firmer and harder when shifting, the ability to shift quicker came from moving more fluid

[chris davey]

hence why Dennis wants to increase the line pressure in his.

Probably not as good as a "real" shift kit but for about $2 to do, if it works ok then it is a good idea I reckon

[2JZR31]

im wondering if this mod ends up killing your gearbox in some way.

nothing is free

Eldar.O.

If you had bothered to read the link I posted. You will see that the whole point of this mod is to extend the life of the trans, and was designed by auto trans experts

[2JZR31]

its not usually springs under the accumulator i thought that made the box shift quicker, that just makes it firmer and harder when shifting, the ability to shift quicker came from moving more fluid

I thought it was the other way? I thought the springs/shims will decrease shift time. And pressure will both decrease shift time plus make the shifts faster..

[wiso]

yeah perhaps your right, i don't fully understand auto boxes, as probably not alot of people do, i was just going off what i was told by micheal, or what i understood from what he told me.

good luck with this

[2JZR31]

I don't know that much either. But my knowledge is getting better as I go. The best way to learn is to get stuck into it

From what I gather, the quicker the accumulators fill up the faster the shifts will be. Springs will achieve that and so will line pressure as the more flow there is the faster they fill up. The extra line pressure applies more pressure to the clutches as well which gives a firmer shift.

If someone has a better and more technical explanation I would like to here it

[wiso]

yeah i didn't know anything about auto's till i pulled my vavle body out, then when i put the torque converter on i learnt more, then i pulled the oil pump out, then accidently pulled the planetry gears behind that out, needless to say, i needed a new box after i got it back together.

now i have learnt not to fuck with them inside

[2JZR31]

I think I will stop at valve body and accumulator mods. I have no intension of going into the reciprocating parts. That looks a bit too involved for me.