1st Gear Too High

[BarnesBuilt]

G’Day all, new to this so please bear with me, I have a 05 GU4 with the factory intercooled and turbo charged 4.2 diesel; the exhaust has been changed to 3”. I tow a caravan and while once the car is rolling it has quite a lot of pull, taking off from a standing start can be an issue particularly on an uphill gradient (feels like first gear is too high). Can anyone suggest any inexpensive adjustments/modifications that can be done to improve the vehicles capacity to move off from the start under load without having to slip the clutch?.


BarnesBuilt

[4bye4]

Is that the original motor and what wheel size on it? Wondering if the diffs are incorrect ratio for towing a van.

[Winnie]

What size tyres do you have?
You could change the diff ratios, which will give you a bit more not only when taking off but right through the rev range in every gear. The engine will rev higher to achieve the same speeds though.

[mudski]

I think you will have 3.9's for diff ratio. Changing to 4.11's will help greatly, or even 4.3's but you will lose top end the higher you go. I went from 4.3's to 4.11's when I did my ZD to TD conversion as 1st was virtually non existant, pulled like a freight train but very annoying to drive in town.
Maybe getting a dyno done of the car to give you more bottom end go might help. As the TD's in stock form are lacking in bottom end go go. Cheaper than a diff swap, may help, it may not. But atleast your car will go better anyway with a dyno tune. I don't really think theres much you can do, on the cheap side of things, that will help.

[Robo]

Hi Mate.
I noticed the same problem on mine. To the extent one could dem it dangerous, trying to get going at a intersection.
That is now a thing of the past with new DC3 injection pump ( Diesel Central, in QLD).
Reco injectors.
GTX2863R Turbo.
3" exh.
lot of other bits n pieces, and a dyno tune the build your choice etc.
And 4" stainless snorkel and pod (Radius Fabrication in Qld also).
After fitting all bits, "except the snorkel & pod" then driven for a week,
the car performed heaps better with the new snork and pod pre dyno tune.
The std air box is a dud for the 4.2.

Our car is a completely different animal to drive now, touring pulling 22ft van is now a breeze.
including those long steep hills and hard take offs, up hill etc.
Fuel consumption down and torque up lots (when needed, it's all in the right boot).
Its a fair bit of coin but in my opinion worth every penny.
And don't worry, it's still Very street-able to drive every day.
My wife loves "her" car now, regularly telling me how well it goes up this and that hill now.
Cheers

Oh I did read some where, up till around 2003 manual box has a higher first gear , but your 2005 so thats covered.
Your compliance plate for axle should denote the ratio you have.

[MudRunnerTD]

If it's never been on a Dyno then expect to get up to a 30% gain drive in drive out. The TD42 is retarded out of the factory. Worth every cent. Beyond that I agree the cheapest upgrade by a lot would be a ratio change. It will provide you an immediate upgrade throughout the gearbox.

What Robo has described above would be AWESOME! But not cheap. I want one though!!

[Maxhead]

Geez, I would have thought the turboed 4.2 should pull the van with no issues. These motors have heaps of torque down low.
Sounds like a good tune is in order.

I tow a 2.7T van with my 3L and have no issues taking off but yeah it is a much better motor....LOL. What you reckon Westy

[mudski]

Geez, I would have thought the turboed 4.2 should pull the van with no issues. These motors have heaps of torque down low.
Sounds like a good tune is in order.

I tow a 2.7T van with my 3L and have no issues taking off but yeah it is a much better motor....LOL. What you reckon Westy

Out of the box Kris your ZD has more go in it than a stock TD42t/ Ti. They just need that little tickle to get them going.
For the op, like i said, the cheapest thing you can do is a dynotune. You may be surprised.

Sent from my SM-P600 using Tapatalk

[BigRAWesty]

Geez, I would have thought the turboed 4.2 should pull the van with no issues. These motors have heaps of torque down low.
Sounds like a good tune is in order.

I tow a 2.7T van with my 3L and have no issues taking off but yeah it is a much better motor....LOL. What you reckon Westy

I'm still on the fence lol

[nissannewby]

1st gear is taller in the gu box. Then for whatever reason nissan decided 3.9 ratios were good in the td42ti wagons. A tune will help a bit but a diff ratio change will get you closer to what you want to achieve.