how to improve gu auto gearbox

[my third 256]

just found this click on the link
http://www.automatictransmission.com.au/release.asp?NewsId=8169
sounds like a good idear dont know cost though
stephen

[Chaz]

Make sure you’re sitting down when you ring for a quote.

Most of us just change the 12 Ohm line pressure dropping resistor for a 1K or 2K 20W resistor which improves shifts for about $5.

[Maxhead]

Make sure you’re sitting down when you ring for a quote.

Most of us just change the 12 Ohm line pressure dropping resistor for a 1K or 2K 20W resistor which improves shifts for about $5.

Agree with above. This little mod is a must in my book, no slip in gear changes and the box would probably stay cooler. I've gone with1k and suits my needs. Theres a few variances of resistors you can use.
Chaz, I believe you've done a diagram on how to wire it up??

[YNOT]

I think this is one of Chaz's diagrams. This circuit lets you switch between the factory 12ohm resistor and (in this case) 1012ohm.

http://i758.photobucket.com/albums/xx224/tonyh01/Resistorcircuit_series.jpg

Tony

[boggy2006]

hi, does this mod apply to the GQ as well?

[YNOT]

Yes it does.

Tony

[Chaz]

I think this is one of Chaz's diagrams. This circuit lets you switch between the factory 12ohm resistor and (in this case) 1012ohm.

http://i758.photobucket.com/albums/xx224/tonyh01/Resistorcircuit_series.jpg

Tony
Yep, that’s the one Tony. I’m still using that setup and have found it useful when doing a lot of low range work. Some times it just shifts too hard with the 1K resistor in circuit, so switching back to the factory 12 ohm job makes it a lot smoother.
http://www.chaz.yellowfoot.org/images/dropping_resistor1.jpg

[boggy2006]

looks interesting, where is the TCU located and is there a connector on pins 1&2 already with the 12 ohm resistor across them or is it something that needs to be added?
Many thanks

[Chaz]

looks interesting, where is the TCU located and is there a connector on pins 1&2 already with the 12 ohm resistor across them or is it something that needs to be added?
Many thanks
Boggy2006,

You don’t need to access the TCU for this mod. Both wires are the 2 that go to the plug for the voltage dropping resistor.
The TCU is behind the passenger side kick panel.

[boggy2006]

sorry to be dumb, I thought it was the ECU behind the passenger panel. And is the resistor somewhere close by?

Thanks again.

[YNOT]

The resistor is on the outside of the firewall where the clutch master cylinder would be on a manual car.

Tony

[Chaz]

sorry to be dumb, I thought it was the ECU behind the passenger panel. And is the resistor somewhere close by?

Thanks again.

The ECU is in the centre of the dash behind the heater controls.

[Bigrig]

Yes it does.

Tony

So when am I coming over so you can hook this up for me??? LOL!

But seriously .... When??


Sent from my iPhone using Tapatalk

[boggy2006]

ah, found mine in a slighly different place on the drivers side inner wheel arch near the firewall! Makes quite a difference unplugging it, so will try a 1k resistor.

ps, if the max voltage across the resistor is 12v, a 1k resistor would need to be about 0.15W min. (V squared / R = 144/1000)


cheers

[YNOT]

So when am I coming over so you can hook this up for me??? LOL!

But seriously .... When??


Let me get the resistor and switch and we'll organize a time from there. Work out where you want the switch.

Tony

[Bigrig]

Let me get the resistor and switch and we'll organize a time from there. Work out where you want the switch.

Tony

You are a champion!!! I'll PM you ...

[my third 256]

can we have some pics please when you do this mod BigRig thanks
stephen

[Bigrig]

can we have some pics please when you do this mod BigRig thanks
stephen

Will do mate.


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[boggy2006]

did the mod on my GQ. A 3K resistor was a bit too much, gear change from 1-2 was too harsh so settled with a 1.2k resistor. 1-2 ans 3-4 noticeably faster, 2-3 quicker too, but still a bit sluggish. A standard 1/4W resistor worked fine, hardly gets warm.

Not sure if the original position of my 12ohm resistor is standard, but here are some photos showing its location. It was easy just to unplug the harness, fold the legs over on the new resistor and insert it into the harness end connector. A bit of tape over the end wil keep it in place, although you might want to do something more permanent.

[YNOT]

So when am I coming over so you can hook this up for me??? LOL!

But seriously .... When??


Sent from my iPhone using Tapatalk

I have the resistors Scott.

Tony

[YNOT]

Not sure if the original position of my 12ohm resistor is standard, but here are some photos showing its location. It was easy just to unplug the harness, fold the legs over on the new resistor and insert it into the harness end connector. A bit of tape over the end wil keep it in place, although you might want to do something more permanent.

I think that may be the standard position on a GQ, that's about the same location as the resistor in my Terrano-which will also be getting the mod done.

Tony

[Bigrig]

I have the resistors Scott.

Tony

Bootiful - how are you placed for the weekend?

[YNOT]

I'm planning to be home most of the weekend. How is Saturday arvo for you?

Tony

[Bigrig]

I'm planning to be home most of the weekend. How is Saturday arvo for you?

Tony

Perfect - you want to PM or text me your address and a time that suits you - I'll bring Tank and a can of rum and coke to share (separate straws of course!!! LOL).

[YNOT]

Perfect - you want to PM or text me your address and a time that suits you - I'll bring Tank and a can of rum and coke to share (separate straws of course!!! LOL).

PM sent.

And you better not back wash!

Tony

[Bigrig]

PM sent.

And you better not back wash!

Tony

Deal!! LOL

[Cadbury]

Hi all,
So what does this mod actually do?
Cadbury

[YNOT]

Hi all,
So what does this mod actually do?
Cadbury

Fitting the extra resistor increases line pressure in the transmission, the result being faster and firmer gearshifts. In some situations faster/firmer shifts may not be desirable, that's why the circuit shown in an earlier post has a switch to bypass the mod and return the transmission to normal.

Tony

[Barney56]

In my auto I've noticed a sort of delay/dragging as it changes up through each of the gears - is this the operation that the resisitor improves?
Barney

[Chaz]

In my auto I've noticed a sort of delay/dragging as it changes up through each of the gears - is this the operation that the resisitor improves?
Barney

Yes it is. These Nissan Jatco transmissions are well known for being a silky smooth gearbox, but it's detremental to their longevity. If, like me, you prefer a sporty and sharper shifting transmission, changing the resistor will help.

[Bigrig]

I ripped mine out - made a little difference to the changes (1000 ohm) mainly second to third, but apart from that, not overly noticeable - something we'll have a lash at again down the track once the new engine is in ...

[shaun100]

Hi All,

Thread dig I know, but is there anyone in Perth willing to lend a hand doing this.

OR:

Is there a good write up with pics on how to do this with an 02 GU 4.8l Auto.

getting tired of the crappy shifts.

Cheers

[taslucas]

If you've got the dollars, go the Nomad Heavy duty valvebody. Ive put one in my TB42 GQ and it shifts like a sports car:) A few others that have done it are also very happy with the result. Im in the process of talking a mate into putting one into his TB48

[Shane'0]

G'day all. My name is shane I have a 2002 wagon st plus 4.8auto 5 speed. I looked for the voltage resistor but cannot find it thanks guys

[shaun100]

Has anyone ACTUALLY done this to a 4.8 GU, it seems more like GQ's here?

If so any pics etc?

Thanks in advance

[jgoose]

Hi mate i know its been a while since you asked & you might have already sorted it out but ill put my 2 bobs worth in ive got a 98 4.5 gu second owner & i unplugged mine before i left the car yard the salesman had no idea wot i was doin. Mine is mounted on the drivers side firewall on the removable gold anadised plate where the clutch master cyl would be on a manual. Ive left mine unplugged for approx 6yrs now & havnt had a prob with it & im usually towing a car trailer i learnt about this mod with company vehicles i use to work on. Hope this helps

[shaun100]

I dont have anything on this anodised plate.......

[04OFF]

On my GU, i just keep the auto transmission swich on the centre console in "power" mode, doesn't this do the same thing anyway ?

[shaun100]

I dont have a power switch either....LOL

[Clunk]

I dont have a power switch either....LOL

You don't have a Power/Auto/Hold switch somewhere on your dash or centre console?

Tapping on the Tab via MC

[shaun100]

Only the "snow" one......Unless its hidden..mines an 03

[june]

i fitted the heavy duty valve body. cost $900 and worth every penny. tow 3 tonne with ease, especially with manual lock-up torque convertor switch. transmission shifts are super crisp,auto temps are low, fuel economy is better. for towing heavy loads I think it is a good mod.

[jgoose]

Hi june where did you get the H D valve body off

[june]

wholesale automatics. check out the link on this first thread

[ripper]

I've been planning to do this resistor upgrade for about two years, and this week I'm finally getting to it.

Does anyone know how many revs you need for the torque converter to safely lock with a 1000k resistor? I think with the original resistor you need about 1800 revs.

Thanks for the GQ resistor location photos (http://www.nissanpatrol.com.au/forums/showthread.php?2471-how-to-improve-gu-auto-gearbox&p=33293&viewfull=1#post33293) Boggy and the wiring diagram (http://www.nissanpatrol.com.au/forums/showthread.php?2471-how-to-improve-gu-auto-gearbox&p=31860&viewfull=1#post31860) Chaz.

[patrolman123]

Wholsale autos are the best in the game with 4x4 autos. Lockup kits and valve bodies a relitivly cheap and make a bumch of difference

[ripper]

Finally did this, but I'm confused.

Tried a 2.2k ohm to start with thinking it could be a bit harsh. That didn't seem to be much different, so I unplugged the resistor completely and it's still not harsh on the changes except for when I manually change up under light load. It does seem to automatically hold it in the gears longer sometimes.

The box was reco'd about 20,000 K's ago, and the fluid was recently flushed with genuine Nissan ATF. It didn't slip when I tried to get it to, and often changes gears so smoothly I don't feel it.

Any ideas on why it's not much different?

[bushwacker]

I just unplugged mine today and it doesn't seem harsh really just feels good and firm much quicker through the gears I'm thinking is there any point putting in a resistor?

[fitzyfootlong]

Cheers for the info fellas

[v502]

Great info :thumbup:

[johno1938]

i had a slight sudder going into o/d
changed oil now ok
does this line pressure mod work on 06 3lt
will it effect o/d shifting in & out on h?way {very annoying }
cheers

[jff45]

The "O/D shifting in and out" is probably your torque convertor locking/unlocking which is not only annoying but is also generating unnecessary heat in the trans.
This is why people fit a manual torque convertor lockup system.. as mentioned earlier in this thread.

[FNQGU]

I'm not an expert on this, but recently have been playing with my auto, and yes this can be one of the reasons people fit the manual TCC lockup. I have one and I use it alot for this same reason, but if I am driving normally at 100kph or above on open roads, then I don't really have the problem. It is normally at slightly lower speeds and undulating highways.

Basically, your TCU has a heap of settings and parameters that dictate when the TCC engages and disengages. Throttle Position, revs, speed etc. It sounds like that position is close to the conditions you are driving at on the highway.

The manual Torque Converter Clutch lockup kit will override these conditions until it is either manually unlocked, or accelerate hard etc.

[ripper]

I've never heard of a manual lockup that cuts out when you accelerate hard FNQGU. Is yours a known brand, or custom built?

[FNQGU]

Pretty sure it does, although I appologise if I am wrong. Might be a setting on the Compushift II that does it. I will have to try it again. There are so many settings to play with on it that it gets confusing.