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M35 Trans Un/lock Mod

Sunkist

By Sunkist,
in Four Door Family & Wagoneers

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Sunkist Grand Master

Sunkist

Posted
Posted

Ok so i finally got around to doing a write up

this is so you can keep the tourque lock up clutch unlocked whilst in Manual mode.

you should notice abit better acceleration

transmission doesnt get so hot in Manual Mode

firstly this was scotts finding so thanks to him for sharing this :cheers:

things you'll need.

soldering iron and soldering wire

wire cutters

4ohm 10 watt resistor

small terminal spade(or similiar)

small bit of wire

first thing is to locate the trans ecu

its under this cover

post-77654-0-30316100-1308442170_thumb.jpg

you will need to remove the "hockey stick" strip cover on the door side of the foor.

and then remove this plastic nut under the glove box, behind the floor mat

post-77654-0-96943200-1308442192_thumb.jpg

You will see the trans ECU with a concuction of wires.

post-77654-0-02500500-1308442368_thumb.jpg

You will need to cnip the yellow wire in the above picture. its the second wire on the first row from the left.

the wire coming out of the ECU side will need to be soldered to one end of the resistor. the other end of the resistor will need to be soldered to abit of wire -> then to the terminal spade.

The spade will then need to be earthed.

Your Done.

If you want to wire a switch to this, you will need to get:

an on/on switch

and some wire(enough to where you want to run the switch)

Im sure you all know how to include a switch into the process. if not, i dont suggest you doing the mod yourself!

hope its effective,

Aaron

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https://www.sau.com.au/forums/topic/368229-m35-trans-unlock-mod/
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Commsman Veteran

Commsman

Posted
Posted

Thanks Aaron / Scott for the info.

I read in a misc post that when the g'box is modded , if left in drive, it will try to get into 5th sooner & could cause a slightly higher fuel consumption. If that's the case, it's a good reason to have a switch so you can return it to normal for dawdling around town, if that's your thing.

I also got the impression that the g'box would hold the chosen gear when driven in manual mode, ie more like a manual gearbox, but that sounds like the opposite of your comment that "you can keep the tourque lock up clutch unlocked whilst in Manual mode". Am I just misunderstanding?

Just so the expected result is more clear, can you explain what you experience (in laymans terms :)) with this resistor to earth mod?

Also, do you have the ECU pin number for the yellow wire?

Cheers, Leon,

Sunkist Grand Master

Sunkist

Posted
  • Author
Posted

Thanks Aaron / Scott for the info.

I read in a misc post that when the g'box is modded , if left in drive, it will try to get into 5th sooner & could cause a slightly higher fuel consumption. If that's the case, it's a good reason to have a switch so you can return it to normal for dawdling around town, if that's your thing.

I also got the impression that the g'box would hold the chosen gear when driven in manual mode, ie more like a manual gearbox, but that sounds like the opposite of your comment that "you can keep the tourque lock up clutch unlocked whilst in Manual mode". Am I just misunderstanding?

Just so the expected result is more clear, can you explain what you experience (in laymans terms :)) with this resistor to earth mod?

Also, do you have the ECU pin number for the yellow wire?

Cheers, Leon,

it holds the gear abit better, which means simply putting your foot down wont change the gears in manual as it normally would. you would literally have to 'floor' it. dont know if thats got to do with the unlocked part but eh

this mode does kind of screw your fuel consumption, which was the original reason why i had the switch, but haven't used it since.

you'll get abit more acceleration as the clutch wont try locking up

i cant remember anything else..

i dont know which pin number it is, but its the torque lock signal or something. im sure scott will have the exam name and pinout

whats the red wire with the red clamp and orange wire coming out?

i dont know, i think it had something to do with the TV.. but it was like that when i got it.

scotty nm35 Grand Master

scotty nm35

Posted
Posted

I have no idea Craig. I could look it up sometime if you like. Mine doesnt have it. I hate scotch locks, whoever invented them is a knob. :spank:

Nice write up Aaron, I couldnt even find the time to drop the kick panel for a pic. :thumbsup:

spoolin12 Collaborator

spoolin12

Posted
Posted

Ok, so I could only find a 3.9ohm 10W resistor (Should work fine right?)

So after installing it, I can't notice any difference. Ex: 4th gear, foot down and it will still jump back to 2nd gear.... have I done something wrong or is it a very subtle difference?....or does the car need to be turned off when switching between the two? >_<

Sunkist Grand Master

Sunkist

Posted
  • Author
Posted

It will only make a noticable difference once your tuned mate, that 30kw I gained is because I'm at 285kw.

Now it's probably like adding a high flow filter. Just know your trans isn't heating up as much.

The resistor is only there to stop the AT light from appearing so I don't think .1 of an ohm is going to make a difference.

Could also take a while to notice perhaps

  • 11 months later...
slippylotion Mentor

slippylotion

Posted
Posted (edited)

I'm thinking of doing this mod as I hate the convertor clutch locking up when in D at speeds as low as 45-50kmph. I sometimes drive in manual 4 so it cant use 5th gear and the clutch lock up. I hate it as when I'm driving at 60kmph and the clutch is locked on its usually got the boost gauge at little to no vacuum or reading 0-2psi if I slightly push the accel pedal and the clutch dosent unlock. I also hate the clutch constantly locking/unlocking when i slighty move the accel pedal. I want to cruise at speeds up to 80kmph with more vacuum as this should result in better fuel usage. Then return the clutch lock to factory at speeds above 80kmph. When I first bought my 180sx it was auto and the clutch wouldn't lock below 80kmph when overdrive was switched on. This is how I want the M35 to be.

So how can I wire it as shown above with a resistor via a switch to keep it unlocked around the city then factory connection for highway? Can I use a on/off switch? My wiring knowledge isn't that great so any help is appreciated.

Cheers

Edited by slippylotion
  • 3 years later...
BoostdR Mentor

BoostdR

Posted
Posted (edited)

Hi all, first of all I don't want to upset anyone with what I'm about to say, I am just trying to ensure the correct info is available to all.

Talking with Mike from MV Automatics here in Adelaide he advised against this mod as it will just increase box wear and fuel consumption with no added benefit.

The M35 RE5R05A in manual mode will completely unlock the torque convertor at anything over 45% throttle input so the switch mod does nothing over 45% tps. An effect will be felt at low-part throttle only.

The ECU controls the transmission shift durations to the extent fitting a shift kit's effect is negated to a % due to the ecu trying to bring the shift duration back to target. This is most noticeable at part throttle when making anything over std power..the trans is prone to slip and groan. The Trans Go shift kit whilst does make a noticeable difference at higher throttle openings, the reason it is still smooth down low is the ECU bringing back the longer/smoother shift durations.

Personally I feel a boost controller mapped with tps on the x axis and boost on the y will most likely reduce M35 owners blowing up their transmissions as it would be able to restrict the torque levels at part throttle to the transmission ecu's controller shift duration zone. Another work around could be a TECU load input convertor to fool the ecu into thinking the tps is higher without effecting fuel and ign mapping in turn giving shorter duration shifts at lower throttle openings

He did recommend the thermistor and oil cooler mod and said there is no down side. He also mentioned if you want a better dyno figure to lockup the torque convertor, this will also reduce torque multiplication in the mid range however

I would like to hear if anyone has actually monitored the lockup clutch in manual mode to see if it does indeed lockup at full throttle as indicated in this thread. I'm going to check mine at the shop with the scope tonight.

Will report back to confirm or dismiss Mike's comments

Matt

Edited by BoostdR
  • Like 1
BoostdR Mentor

BoostdR

Posted
Posted

Testing tonight showed that mikes comments held true for normal driving mode but as pointed out on previously the torque converter does indeed try to lockup in manual mode from 2nd to 5th gear at any throttle opening position. First gear has no lockup.

I did note the lockup solenoid starts at 0.3amp and Ramps to 0.5amp Max.

I tried to stall the car up and confirmed the brake wire mod was giving 100% throttle opening.

The TCM however was still getting a brake signal.

5th gear comes active at 66 degrees trams oil temp and over.

My Gscan tool also showed a power switch setting which interests me, would be nice if this switches the TCM to different maps.

Matt

post-49288-14410133867762_thumb.jpgpost-49288-14410134020105_thumb.jpgpost-49288-14410134136496_thumb.jpgpost-49288-1441013421477_thumb.jpgpost-49288-14410134295366_thumb.jpg

scotty nm35 Grand Master

scotty nm35

Posted
Posted

Been running the torque converter with no lockup for 6 years now, I can't stand the way it locks up constantly in manual mode (nor can the trans). It's a pwm signal, not hard 12V, although that's what I used to throw at the solenoid on the dyno. Now I just leave it off.

Fuel economy, what's that?

Edit: Looks like Mike has a bit to learn with regards to the RE5. It isn't anything like the RE4.

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