Auto gearbox modification

[BUSHWHACKER]

Surely your truck must be about 13

Nope, 12. And don't call me Shirley.

[dazandcaz]

Surely your truck must be about 13

[BUSHWHACKER]

http://www.ebay.co.uk/itm/REMOTE-CON...item484cc54b96

Very sad indeed.

For a five year old?

[dazandcaz]

BTW i am in no way affilliated with the producer or seller of this item and dont even think about asking for a free sample

[dazandcaz]

http://www.ebay.co.uk/itm/REMOTE-CON...item484cc54b96

Very sad indeed.

[BUSHWHACKER]

Where's my scanner?

[wasp132]

ooh! did you ever make a kit? I'd buy one

[adpsimpson]

Did this project get finished, and with good results or what? H

Hazzo, I'd started a new thread for my modifications, here. As far as I know, Andy (Apache) currently has a simple switch to change between automatic control of the torque converter lockup and override (always locked up). I was attempting full manual gearbox override, with some (but not complete) success. I've just posted my progress there.

[Hazzo]

Did this project get finished, and with good results or what? H

[Apache]

Sync between auto and manual is something (of pretty high importance!) I hadn't considered. Nice one for spotting it

[adpsimpson]

I now have a breadboard with 8 ICs, one relay and about 50 resistors on it. It can reliably lock and unlock the torque converter, display what gear you're in on a 7 segment display, and generate the signals required to override the automatic gear selection.

All that's left is 2 more relays to send the gear-changing signals to the gearbox instead of the ECU signals, and one more relay and a Big, Solid Switch to turn the whole thing on and off.

Then it'll need tested in the Surf, of course. Assuming it works as planned I'll draw up circuit diagrams to get a PCB made, and post everything here. I'd also be happy to put together kits if anyone else fancies having a shot at it.

Since I've not touched any electronics since the Edinburgh Science Festival when I was about 8, it's been a steep learning curve - I've also had to spend 3 or 4 times the value of the components on stocking up, prototyping boards, etc. I reckon the total value of components is about £20 (much of that is the 4 relays), although it could be brought down by more careful buying.

The gear changing counter (CMOS 4029) has a presetable output, so when in auto mode I'm continually feeding it with the current gear number and continually resetting it. That means that whenever you change to manual, it stays in the same gear as it was in. When in manual the preset number is still being fed with the ECU's favourite gear, so a simple push button could 'synchronise' the gear to a sensible selection. Not sure if that would be useful yet though.

It would also be pretty simple to automatically synchronise the manual selection every time the auto box wants to change to 1st gear (ie when you stop), which might be more useful - kind of a simplified version of what Vince was suggesting. Think I'll put this function in with a jumper on the board to turn it on and off, so I can play and see which way I like it.

[Apache]

There is a brake signal to the ECU. I checked that when I started out with the design work. I'm bu99ered if I can find the diagrams now, I think they're on my old laptop.

[adpsimpson]

Right, got it working last night and went for a drive this morning. It did just need a diode to buffer the lockup solenoid, nothing else, and it pretty much does what it's meant to.

I'd already done a very simple manual override (on/off switch), and now have a 7 segment display to say what gear it's in. Thought that would be a good launch point to start the manual control, so picked up a nice simple volume control paddle from an old Laguna today. It's got + and - buttons, with an extra one on the top and one on the bottom - ideal for system manual/auto, lockup on/off and change gear. Also got a roller on the back which I'm sure I'll find a use for...!

Was thinking a 7 segment display using the point to mean lockup, with a separate LED to mean auto/manual mode, all mounted in the space in front of the 4WD selector stick, with the buttons on the paddle doing all the control.

I've not yet included the brake signal, which is pretty important - slowing through the 20-30mph zone is pretty unpleasant (and not to good for the truck) while in lockup. Accelerating through it is fine if ECT is on. Anyone know offhand if there's a wire live when braking anywhere near the ECU? Couldn't see one in the ECU pin-out, Andy you suggested the brake lights wire, any hints where that's located to stop me digging around?

Vince, did you get anything useful?

[Apache]

I'll see if there's a wiring diagram for it on my workshop CD, might be of some use to you whiz kids.

It'll amost certainly be programmable logic, or software in an ECU somewhere Vince, and pretty difficult to replicate in off the shelf parts. It would be good to know the logic flow though, if thats included.

[Apache]

To keep the thread updated, he suggested putting a diode between the solenoid output (lockup out) and earth, as the solenoid may be causing inductive spikes which could keep the mosfet open, causing the NOR gate to behave badly.

Makes sense, I'll try it this evening and post back.

Apache, did you ever build your circuit, or just install a simple flick switch? I've got that in just now and it works, but isn't exactly nice at low speed.

Didn't get around to building it. Too much else on my plate really.

However, I expect your mate is on the right track in that the loads are causing odd responses from the gates. Can you get your hands on a scope and have a look at the gate inputs while the system is operating?

I was giving it some thought today in work, and thought about maybe buffering the inputs with schmitts, and possibly the outputs with darlingtons. That would at least give the logic stable, less noisy loads to work with.

Why not start with manual control of the solenoids via a debounced 'counter' of some sort, so you can only get the gears in sequence via a couple of pushbuttons (up / down) and include lockup when 3rd is selected. You would then drop out of lockup on the way down the gears again. The foolproof features can be added later.