Another auto gearbox question.

[Apache]

So my box is three speed + OD. There are two shift solenoids. Presumably, there is 1 solenoid for 1st, 1 for 2nd, and the pair for 3rd? OD then works a different way based on some hydraulic mechanism?

So, I'm thinking its going to be reasonably easy to control the box manually, as well as manual lock up.

Its only going to be a matter of logic circuitry to prevent things like stopping in lockup.

Any thoughts folks?

[nero279]

I may have misread blizzard's thread, but i understood that to read

Solenoid 1 - controls shifts from 1st to 2nd & vice versa
Solenoid 2 - controls shifts from 2nd to 3rd & vice versa
and Solenoid 3 - controls shifts from 3rd to OD & vice versa

or was that something else he was talking about? You definately only have two solenoids?

[TonyN]

There are 2 shift solonoids, and the lock up solonoid.

the 2 solonoids on or off in different sequences control the 4 gears.

In D....
1 on 2 off =1st
1 on 2 on =2nd
1 off 2 on =3rd
1 off 2off =O/D

in 2nd...
1 on 2 off =1st
1 on 2 on =2nd
1 off 2 on =3rd

in L..
1 on 2 off =1st
1 on 2 on =2nd

[Apache]

Excellent thanks Tony! Thats what I need.

It might be an obvious question, but I take it :-

1 off, 2 off = neutral?

<doh!> Just noticed OD is both off.

How do you get neutral?

[Apache]

I may have misread blizzard's thread, but i understood that to read

Solenoid 1 - controls shifts from 1st to 2nd & vice versa
Solenoid 2 - controls shifts from 2nd to 3rd & vice versa
and Solenoid 3 - controls shifts from 3rd to OD & vice versa

or was that something else he was talking about? You definately only have two solenoids?

No mate, 3, but the third is only TC lockup.

[BUSHWHACKER]

I've got 4.

[Apache]

You used the Lexus box then Vince?

Some Lexii use the same box as me

[TonyN]

No mate, 3, but the third is only TC lockup.

think neutral is just mechanical.

but you may find this interesting.....

Neutral to drive squat control:

When the transmission is shifted from neutral to the drive range, the ECU prevents it directly shifting into first by causing it to shift into 2nd or 3rd before it shifts to 1st. It does this i order to reduce shift shock and squatting of the vehicle.

This manual is for a US V6 3rd gen, so don't know if this is fitted to earlier deisels, but interesting none the less, and its the same box, just different transfer case.

[TonyN]

I've got 4.

A340H?

[Apache]

think neutral is just mechanical.

but you may find this interesting.....



This manual is for a US V6 3rd gen, so don't know if this is fitted to earlier deisels, but interesting none the less, and its the same box, just different transfer case.

Hmmmm, yeah, I can understand the reasoning behind that. The ECU for the 343F box does seem to have been fitted to the V6 2nd gen 4Runner, so it could be the same... I'll find out when I start playing.

Sooo, if I was gonna effect some sort of manual override, neutral to drive selection could remain on the main stick, which would then select a higher gear to prevent me spearing into the back of the car in front (!) and as I press the (hopefully steering wheel mounted) button for 1st, it will also take control from the ECU to my grubby little thumbs

I'm just trying to get a logic flow sorted in my head here, but I am feeling quite excited about this. It all looks much easier and more flexible than I dared think!

I like the idea of a digital indication of gear selection derived from the solenoid drive signals set into the instrument panel - that should be a piece of p1ss as they say - and it would tell me what gear the box is selecting when I go from neutral to drive.

[BUSHWHACKER]

A340H?

A341E. The 4th solenoid is just a damper to smooth out the gear shifts.

I can't feel the transmission shifting at all.

[Blizzard]

Hello,

If you already have the auto ECU, and you've it, you can put one of those:

http://awshifting.com/

I can't use this because I'm converting my manual to auto.

BUSHWACKER, did you know that having the tranny shift with low pressure makes the shifts softer but adds wear to the clutches? In my swap I'm blocking the throttle cable at WOT position (You can do it too on Surfs) and shimming two accumulators so the shifts are a bit harder but this way you make the tranny bulletproof.

David

[BUSHWHACKER]

Hello,

If you already have the auto ECU, and you've it, you can put one of those:

http://awshifting.com/

I can't use this because I'm converting my manual to auto.

BUSHWACKER, did you know that having the tranny shift with low pressure makes the shifts softer but adds wear to the clutches? In my swap I'm blocking the throttle cable at WOT position (You can do it too on Surfs) and shimming two accumulators so the shifts are a bit harder but this way you make the tranny bulletproof.

David

Yeah, I read about that, but doesn't it put extra wear on the rear diff and U/Js?

[Apache]

Hello,

If you already have the auto ECU, and you've it, you can put one of those:

http://awshifting.com/

I can't use this because I'm converting my manual to auto.

But that would be the easy option. Half the reason I'm doing it is for the fun of designing the electronics myself.

Interesting to read your thoughts on the harder shifting. Is it hard to implement? I can set the WOT input on the ECU to the level required, but what effect does shimming the accumulators have?

Check the thread in 'Modifications' to see where I'm at.