Thread: Manually locking D2 TD5 Torque converter

This is a great idea!!!!

Even locking into 4t at 60 would be great.
I reckon under light load when in 4th lock I can cruise down to 60 anyway.
Mine currently locks to 4th at about 85 , it's too high

Originally Posted by PsiDOC

I have been looking into the same things myself. I have always felt that the lockups were all wrong. 50 mph (80 kmh) in third to lock the box up is way too high particularly when it's in lock you can pootle all the way down to 35 mph (56 kmh) in third and keep it locked, so why not lock it at 37 (60 k's) and then 47 mph (74 k's) in 4th.

The Mosfet used to engage the lockup solenoid is a IR952. Source to ground, drain to output. So you can splice into the wire on pin 32 and lock it manually by grounding through a switch without causing any damage to the mosfet. Although there is a feedback circuit to monitor the health of the solenoid on the output of the mosfet so it might go into fault mode. Only way to find out is try it.

Its possible that the pin only needs to be grounded for enough time (eg 500ms) for the electronics to accept the lockup then leave it to decide whether load and speed conditions are acceptable to retain the lockup, only unlocking when it needs to such as for gear changes. I up-shift and down-shift my D4's box early by grounding the up-shift and down-shift request wires for a short period and providing the conditions are acceptable the higher or lower gear will be retained. I have a remote control fob stuck to the side of the steering wheel for easy access to button switches and the controller in the engine bay that switches inputs to a module that limits switching "on" time to prevent faults if a button is held for too long.

I tried to get used to the D2 auto box's TC slip when getting a replacement for a manual TD5 D2 to make driving easier for my wife with her bad left leg but I couldn't live with the engine moaning whilst pottering around the streets.

A word of caution.


The auto is programmed to never change gear while in lock up mode, do you not think this is for a good reason, not only because of the harsh changes but also the life of the transmission. That's why I won't be making any changes with mine even though the idea of extending the lock up is attractive.


Nick

Graeme,
Sadly the D2 TCU does not have an external upshift / downshift request to tie into otherwise it would be ideal and I wouldn't have this battle on my hands. The switch method discussed originally is actually switching the solenoid manually in and bypassing the TCU completely. I do like the idea though and nicely done on the D4. Will keep that in mind if I ever get enough money to own one.

Pippin, You are correct and this must be kept in mind. Although, If I can find the correct lockup maps in the TCU then it will never shift whilst locked as lockup 3rd only occurs with the gear lever in position 3 and lockup 4th obviously in D. The automated sequence of shifting between lockup in 3rd and lockup in 4th is.

On moving the lever from 3 to D at above 55 mph so 3rd is in lockup and 4th lockup can be achieved immediately:
1: Unlock 3rd.
2: Wait 1 second.
3: Shift 3rd to 4th
4: wait 2 seconds
5: lockup 4th.
Which makes sense as you need to allow the kinetic rotational energy to stabilise and of course the pressure in the box will have changed up to 3 times.
With that in mind for the lockup I am of the opinion the modded controller maps are the way forward as you will never get a gear shift with the TC locked.
Using a programmable external lockup controller I can detect a gear shift by monitoring the solenoids and speed and also more than likely predict when the shift will occur.
That however is for another day. I'm sticking with the controller maps for now.

Hope that clears things up a bit.

Si

Time for a bit of thread mining.

Has anyone who has done just a switched ground between pin 32 and earth got any info on how its worked out?

I do a bit of towing every now and then with my auto TD5 and to be honest I don't like the converter not locking up enough, especially with some of the roads I tow on.

Option 1 that I'm looking at is the Ashcroft heavy duty TC as I have only read good things about it.

Option 2 wire in switch to earth pin 32 when I want it and obviously have it selected to a particular gear when doing so.

Even if I were to get the heavy duty TC I still believe it would be worthwhile to be able to lock the converter in 2nd on my way up a very steep pass from Greymouth to Christchurch (NZ). The amount of revving all the way up that hill to me is not a good thing and maintaining a speed to be locked in 3rd really isn't a goer either.

Thoughts ideas?

Cheers.

So, how does this system compare? Would be interested in any comments. Retails for somewhere in the vicinity of $500AU

I feel $500AUD is a bit steep for that GenII kit that appears to be a switch and resistor.

Suprastick

[ame]http://www.latentsolutions.com/SSv4.6.pdf[/ame]

Many years ago, I had an MX83 cressida with a 7mgte vfrom a toyota supra fitted, the factory box had been "manualised" with a bunch of relays and transistors, using the shifter L, 2, D and OD button) to manually engange the clutches in the box, all worked well, but U had no locup in anything other than 4th, and, if U jumped on the brakes whilst the tranny was locked, u would stall the engine.

I looked into the above "Supra Stick"as an alternative, that allows U full manual control over the box, or, the option to revert to full auto.

Could something like this be modied to suit the D2 autobox purpose???
A tiptronic style auto would really bring it into the 21st century.