Btr Transmission Mod

[turbotrana]

To all the guys running serious mods thru their Auto trans that are having a hard time having it hold clutches and bands.

The cats out of the bag so I might as well be the first on this forum to tell everyone about it.

Disconnect S3 and S4 solenoids (somewhere close to the computer) and put a dummy load to earth, dummy load for each solenoid should be a single 27 ohm 5 watt resistor to ground, one for each wire on the computer side to stop computer going into limp.

I've been using this for a while with absolutely NO line pressure mods and it gives very hardshifting shifts. For us hardcore guys this mod is worth its weight in gold as it will save the bands and cluches in the trans. (long term consequences not exactly known at this stage, but what ever they are, the trans will still last longer than not doing it). The pussys who like soft shifts wont like it but I have also done this mod to give soft shifting on normal driving and hard on load but that's a whole lot more complicated.

Goodluck with it

[axr-jet]

To all the guys running serious mods thru their Auto trans that are having a hard time having it hold clutches and bands.

The cats out of the bag so I might as well be the first on this forum to tell everyone about it.

Disconnect S3 and S4 solenoids (somewhere close to the computer) and put a dummy load to earth, dummy load for each solenoid should be a single 27 ohm 5 watt resistor to ground, one for each wire on the computer side to stop computer going into limp.

I've been using this for a while with absolutely NO line pressure mods and it gives very hardshifting shifts. For us hardcore guys this mod is worth its weight in gold as it will save the bands and cluches in the trans. (long term consequences not exactly known at this stage, but what ever they are, the trans will still last longer than not doing it). The pussys who like soft shifts wont like it but I have also done this mod to give soft shifting on normal driving and hard on load but that's a whole lot more complicated.

Goodluck with it

Thank's for the info as my chev powered LC runs a power glide, and cherps drive so I dont mind the hard shift.

Edited 22/11/04 07:37 AM by axr-jet

[thebrunks]

Must be similar mod to what Craig & Dean are using!

Basically what shift kits would be doing anyway, except they have a switch to choose different degrees of firmness & seem to be still using the solenoid!

This is the DIY version & seems to be not using the solenoids at all, where as the shift kits version look as though the still do!

Russ

[turbotrana]

This mod has nothing to do with shiftkits.com and is a completely different mod. If every guy who has had his trans sh*t itself did this mod in the first place their trans would probably be intact. Tryit. It does wonders for the holding power of this trans.

[geea]

Exactly how do I do this to try it. Which wires need to be disconected and can I have more info on the earth thing please. I would be keen to have this when I run the 1/4 on my Nitto's on Friday it might help the times. If your will I'd love to have a chat on the phone about this to try to get a better understanding of what needs to be done. :loc:

Geea. :loc:

[Guest]

Exactly how do I do this to try it. Which wires need to be disconected and can I have more info on the earth thing please. I would be keen to have this when I run the 1/4 on my Nitto's on Friday it might help the times. If your will I'd love to have a chat on the phone about this to try to get a better understanding of what needs to be done. :loc:

Geea. :loc:

<{POST_SNAPBACK}>

me too :loc:

[turbotrana]

Its very simple. The S3 and S4 and the S5 solenoids are all there to get a nice soft shifting trans for the pussys out there. This soft shifting (flaring) gets worse as you put more power thru. Switching off S3 and S4 solenoid eliminates the soft shifting so it shifts harder. As a result the S5 solenoid is not used at all by switching the S3 & S4 off. As a result as most rev heads know that quick shifting helps the trans heaps. But for me its no problem. When I put the turbo on my ED the flaring when power put thru would have destroyed the trans. With this mod It shifts great.

This mod also increases line pressure a bit from normal so there could be issues if you have already increased line pressure (but I doubt it).

When you disconnect S3 S4 you have to trick the computer into thinking that they are still there. So for each wire you must put a single 27ohm 5 watt ceramic type resistor which leads to the computer and ground this to the body of the car somewhere. On the ECC4/5 this fools the computer into not going into limp and should do the same to the BA.

Note this mod helps the bands and clutch material survive heaps. If you have no idea what I am on about dont try it.

However this will definately become a mainstream mod.

As a result of disconnect the solenoids, the trans does not do any engine braking. Personally I prefer this.

For people like Geea and Dynowog, if you were in Perth I'd be asking yoy guys to kiss my Ass for giving out this info. that's about all you need to know. Just try it and see how you go.

[turbotrana]

and for working out which are the S3 and S4 solenoid, you just have to check the wiring manual for the BA. Dynowog should have that. I only have it for EA to AU.

[shiftkits.com.au]

For people like craig and dean, who run a lot of 1/4 miles and also use the utes daily for work etc, will most likely need engine braking through the auto.

According to one of my btr manuals, s3 and s4 control the front band and the c3 clutch (although it may be incorrect, I will be picking up the other manual later today) but this will also affect the kickdowns.

Also I got a funny feeling that this will give you maximum line pressure, always (as trana stated the s5 is no longer used, therefore must be providing max pressure)

As far as this mod working in the BA's someone is going to have to give it a try, but the BA ecu is much more critical in trans control, as it monitors a lot more stuff than previous models, so it is a possibility that if you are doing 100km's per hour and back off the accelerator, and the revs drop back to idle, this may be enough to trigger limp mode.

Best way to find out is to give it a go.

(Also just a tip, instead of connecting the resistors from the ecu pins to ground, connect them to the +12v ignition feed, as all the solenoids in the trans are tied to +12v and the ecu provides the ground to them. This will more accurately simulate the solenoids being there)

[F6_Tornado]

You could work this many ways.

I would make a simple circuit board with a few diodes, Resisters and a couple of IC’s.

With this you could work it in any mode you like to have the solenoids modulate or do nothing at all allowing hard harsh shifts.

Some caution would need to be addressed with clutch modulation both on engagement and disengagement by way of engagement of the next gear clutch combination before the previous clutch combination oil decay had taken place.

This would be minimal and I feel with the option to have it “on or off” is a “must” and only use it when required. (Clutch overlap can be advantageous but as long as it’s minimal)

Once the basic board is made you could then incorporate the throttle potentiometer and have it so the 0% throttle position = standard mode and 100% throttle position = No clutch modulation allowing for harsh and direct shifting.

This would then allow a 3 position switch:

Normal

Auto HARD (This would also allow engine braking to still be effective)

HARD HARD

Cost of parts for a simple circuit would be no more than $25.00 and several hours to workout and design the board.

What we as seeing now is the change in mind set from the knuckle dragging Mechanics to some brain work and using what is already fitted and manipulating it to achieve the desired results.

I think people are finally starting to realize the future lies in the management of the existing components on these new vehicles will reward the thinking man without the need to rebuild every damn thing like the old days.

I would stress that people should use the brain and have all these simple mods… but put some brain work in them so the vehicle is still drivable and durable in its normal mode but with the option to turn it into a beast with the flick of a switch.