how to improve gu auto gearbox

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21st January 2011, 12:51 AM
my third 256

how to improve gu auto gearbox

just found this click on the link
http://www.automatictransmission.com...sp?NewsId=8169
sounds like a good idear dont know cost though
stephen
21st January 2011, 02:35 AM
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.
21st January 2011, 07:04 AM
Maxhead

Quote:

Originally Posted by 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.

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??
21st January 2011, 07:53 AM
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/x...uit_series.jpg

Tony
21st January 2011, 07:54 AM
boggy2006

hi, does this mod apply to the GQ as well?
21st January 2011, 08:00 AM
YNOT

Yes it does.

Tony
21st January 2011, 09:11 AM
Chaz

Quote:

Originally Posted by 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/x...uit_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/image..._resistor1.jpg
21st January 2011, 09:37 AM
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
21st January 2011, 10:02 AM
Chaz

Quote:

Originally Posted by 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

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.
21st January 2011, 02:39 PM
boggy2006

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

Thanks again.
21st January 2011, 02:48 PM
YNOT

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

Tony
21st January 2011, 03:05 PM
Chaz

Quote:

Originally Posted by boggy2006

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.
23rd January 2011, 01:56 PM
Bigrig

Quote:

Originally Posted by YNOT

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
23rd January 2011, 05:51 PM
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
23rd January 2011, 07:03 PM
YNOT

Quote:

Originally Posted by Bigrig

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
23rd January 2011, 07:07 PM
Bigrig

Quote:

Originally Posted by YNOT

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 ...
24th January 2011, 04:32 AM
my third 256

can we have some pics please when you do this mod BigRig thanks
stephen
24th January 2011, 10:56 AM
Bigrig

Quote:

Originally Posted by my third

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

Will do mate.

Sent from my iPhone using Tapatalk
26th January 2011, 10:16 AM
boggy2006

3 Attachment(s)

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.
3rd February 2011, 09:20 PM
YNOT

Quote:

Originally Posted by Bigrig

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
3rd February 2011, 09:23 PM
YNOT

Quote:

Originally Posted by boggy2006

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
3rd February 2011, 09:27 PM
Bigrig

Quote:

Originally Posted by YNOT

I have the resistors Scott.

Tony

Bootiful - how are you placed for the weekend?
3rd February 2011, 09:39 PM
YNOT

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

Tony
3rd February 2011, 09:47 PM
Bigrig

Quote:

Originally Posted by YNOT

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).
3rd February 2011, 09:54 PM
YNOT

Quote:

Originally Posted by Bigrig

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
3rd February 2011, 09:55 PM
Bigrig

Quote:

Originally Posted by YNOT

PM sent.

And you better not back wash!

Tony

Deal!! LOL
4th February 2011, 08:16 AM
Cadbury

Hi all,
So what does this mod actually do?
Cadbury
4th February 2011, 11:39 AM
YNOT

Quote:

Originally Posted by Cadbury

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
3rd September 2011, 11:55 PM
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
5th September 2011, 12:32 PM
Chaz

Quote:

Originally Posted by 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

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.
5th September 2011, 12:54 PM
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 ...
18th September 2012, 11:58 PM
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
19th September 2012, 07:35 AM
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
28th May 2013, 09:14 AM
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
28th May 2013, 06:43 PM
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
7th June 2013, 08:49 PM
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
7th June 2013, 09:00 PM
shaun100

I dont have anything on this anodised plate.......
7th June 2013, 09:30 PM
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 ?
8th June 2013, 09:29 AM
shaun100

I dont have a power switch either....LOL
8th June 2013, 10:48 AM
Clunk

Quote:

Originally Posted by shaun100

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

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