Auto gearbox modification

[Apache]

Still early days re. the design Andy, but that is interesting. I'll go the long way home tonight and try that.

I definitely need to sort out an indication of what solenoids are operating and when. I feel some LEDs coming on!

Now I'm into this, I wont be happy until I've got a fully switchable manual / auto box with selectable lockup!

I wonder whether the box changes normally without OD on and with lockup selected - I think you may have put your finger on something there because I reckon with OD on, selecting lockup manually forces the box into OD too...

'Blizzard' seems to understand the mechanical side of the autobox pretty well. Wonder if he can shed some light on this?

[The Lovely Boyo]

Apache - what have you started ????

OK - I've been doing some testing of my own on some quiet, flat roads this afternoon.

Drive around with the O/D off. You will find the shifts are quite pronounced/definite (accelerate at about 2200rpm, don't boher with the ECT). The convertor will still lock up, mine does it at about 45 mph.

Now drive around with the O/D on. It feels like the box now has about 5 or 6 gears. I think the ECU is using the O/D to 'slur' the changes. Much more difficult to check whats going on. At constant revs (again 2200) box almost feels like a CVT!!!!!

There's a lot more going on than you'd think.

[Apache]

I dunno. I'm not sure if the ECU is smart enough.

I dont think it will start in lockup, as I think the latch will always power up with Q bar high.

I'll do a bit more looking into latches and see if there is a definitive way of ensuring that.

[gwh200]

if you dont have a foot on the brake,and/or you fail to note the illuminated light,will it just not start,until the correct procedure is adhered to ??

just like when you try and start in gear ?

[Apache]

Thanks And, looks like interesting reading.

This is first draft of control / failsafe circuitry. Comments anyone? Matt F, i'm looking at you! PLEASE NOTE - resistors connected to inputs of OR gate are connected to 0v, not +12v volts as shown.




Single momentary pushbutton for lock / unlock via 4027 flipflop used as a latch. I'm using the active low O/P as I have then NOR'd the O/P so only a zero on each I/P will allow the operation of manual lockup.

This means I can OR imputs from brakes, solenoid 1 (only active during 1st and 2nd gear) and anything else which you'd like to disable lockup, and feed the output (normally '0') to the other input of the NOR.

Therefore a '1' from the latch (manual disengage of lockup) or any input to the OR gate will cause cancellation of lockup.

Also used the normally closed side of the relayfor the ECU (failsafe), and I *think* the latches start position should be with a '1' on Q bar, so lockup should be off initially. Even if it isn't, foot on the brake to start the engine will cancel lockup, and if lockup is on, there'll be a light in the switch so you can cancel it manually before selecting 'Drive'

Anything else? Any glaring bloopers?

[The Lovely Boyo]

First I need to know why the box doesn't seem to change down in lockup. You chaps dont know?

I've mailed a write up on the toyota auto box to your surf sticker inbox

see if that has any info thats of use.

[BUSHWHACKER]

Which is why (further back in the thread - see post 12) I said that 'brakes', and the signals for 1st and 2nd gear will be logically OR'd in my controller design so stopping in lockup is not possible.

First I need to know why the box doesn't seem to change down in lockup. You chaps dont know?

Evidently, I don't.

[Apache]

Which is why (further back in the thread - see post 12) I said that 'brakes', and the signals for 1st and 2nd gear will be logically OR'd in my controller design so stopping in lockup is not possible.

First I need to know why the box doesn't seem to change down in lockup. You chaps dont know?

[The Lovely Boyo]

"Apache...The only man to stall a Auto"

LOL - I was trying to imagine what it would be like too!

[TonyN]

I would have thought it would need to be essential. With a locked TC you would have 'solid' drive between the engine and the road - that would be interesting when coming to a halt lol

"Apache...The only man to stall a Auto"

[The Lovely Boyo]

Originally Posted by The Lovely Boyo

There's an American company doing these things. One of their features is to allow a 'snow' start - selects and holds 2nd only, apparently can have its uses in muddy conditions too.

We can do that anyway, just select 2 with the lever.

Hi Vince,

If you put an auto tranny to 2nd, it'll start off in 1st, change into 2nd and thats all. No 3rd or overdrive.

But it won't pull off in second.

For someone who has the ability to do an V8 engine swap to the standard you have, I'm quite surprised at you, old chap.

Splasher been causing you some sleep deprivation????????

[Apache]

OK, after a wee drive around this morning, it seems I can select lockup at any point, but at this point, the box 'seems' to change up to top, whatever speed I am doing, and slowing down doesn't 'seem' to elicit down-changes.

I say 'seem' because its hard to tell. I need to build something to display what gear the box is selecting to be sure, but are there any autobox experts out there who might know why the box would change up when selecting lockup?

I have a theory that the ECU might be processing it as "ok, there's lockup - we MUST be in 3rd gear" and selecting 3rd.

[Apache]

Andy, it looks like full manual control should be fairly simple, so selecting and holding 2nd should also be easy (but you have that on the stick?)

I'm planning on using the 1st and 2nd gear signals logically OR'd (along with brake light signal) to deselect lockup, so lock when stopping wont happen. On the version I'm planning, lock will only happen in 3rd or OD, but no reason why I cant make it available in 2nd too.

[BUSHWHACKER]

There's an American company doing these things. One of their features is to allow a 'snow' start - selects and holds 2nd only, apparently can have its uses in muddy conditions too.

We can do that anyway, just select 2 with the lever.

[The Lovely Boyo]

I still think for normal operation an automatic release of lock when in 1st or 2nd would be worthwhile.

I would have thought it would need to be essential. With a locked TC you would have 'solid' drive between the engine and the road - that would be interesting when coming to a halt lol

There's an American company doing these things. One of their features is to allow a 'snow' start - selects and holds 2nd only, apparently can have its uses in muddy conditions too.

Have a go at figuring that out and I'll buy one off you.