Gearbox upgrade

This site contains affiliate links for which LandyZone may be compensated if you make a purchase.
L

langley

New Member
Posts
372
Location
Bristol UK
Having done plenty of research, including a couple of great threads on this site, im seriously looking into upgrading the gearbox and possible replacing the transfer at the same time. I know i want to keep the car and with the power being increased gradually its only a matter of time till the box gives up.

So the questions are:

- Has anyone replaced gearbox transfer on a driveway? Is it possible?
- Assuming i can get the parts to put the zf24 into the car, are there any issues that will catch me out half through the job that could have been sorted before the box is removed or fitted?

Any help greatfully accepted.
 
The 4.0 litre petrol seems to manage not to destroy it's boxes with 190 BHP and 320 Nm of torque. With a PSI powerbox you will get around 165 BHP and 320 Nm of torque max on the diesel, maybe a little more with a dedicated ECU chip. That will not damage a gearbox in good nick unless you tow a house behind you in torque lock. Providing the box is in reasonable health to start with, normal driving is not going to destroy it with that sort of power. However if you feel like playing, play away. You do seem to enjoy it.
 
wammers said:
The 4.0 litre petrol seems to manage not to destroy it's boxes with 190 BHP and 320 Nm of torque. With a PSI powerbox you will get around 165 BHP and 320 Nm of torque max on the diesel, maybe a little more with a dedicated ECU chip. That will not damage a gearbox in good nick unless you tow a house behind you in torque lock. Providing the box is in reasonable health to start with, normal driving is not going to destroy it with that sort of power. However if you feel like playing, play away. You do seem to enjoy it.
Click to expand...

That is the first positive thing ive heard about diesel gearbox, sounds promising, although remember im running a laaarge intercooler as well as the box..

If thats the case, i shall just give the old girl a good service and leave it be, dont want unnecessary issues. But the rangie is going to be only car in the house hold, so i want it to be as reliable as possible for potential day to day usage..

Just need to look at what else may need doing now, so i dont panic when the missus takes it out during the day..
 
wammers said:
The 4.0 litre petrol seems to manage not to destroy it's boxes with 190 BHP and 320 Nm of torque. With a PSI powerbox you will get around 165 BHP and 320 Nm of torque max on the diesel, maybe a little more with a dedicated ECU chip. That will not damage a gearbox in good nick unless you tow a house behind you in torque lock. Providing the box is in reasonable health to start with, normal driving is not going to destroy it with that sort of power. However if you feel like playing, play away. You do seem to enjoy it.
Click to expand...
I have not got time to check at the moment but I think your torque figures are wrong from memory Tony. The box limit is 300Nm, the V8 is below that, the chipped diesel well above it which, along with the lack of torqe reduction on the chipped diesel, is why the boxes fail if the power is used.:)
 
langley said:
That is the first positive thing ive heard about diesel gearbox, sounds promising, although remember im running a laaarge intercooler as well as the box..

If thats the case, i shall just give the old girl a good service and leave it be, dont want unnecessary issues. But the rangie is going to be only car in the house hold, so i want it to be as reliable as possible for potential day to day usage..

Just need to look at what else may need doing now, so i dont panic when the missus takes it out during the day..
Click to expand...

So what, large intercooler will do jack ****. You don't need one unless you have fitted much larger turbo.
 
langley said:
That is the first positive thing ive heard about diesel gearbox, sounds promising, although remember im running a laaarge intercooler as well as the box..

If thats the case, i shall just give the old girl a good service and leave it be, dont want unnecessary issues. But the rangie is going to be only car in the house hold, so i want it to be as reliable as possible for potential day to day usage..

Just need to look at what else may need doing now, so i dont panic when the missus takes it out during the day..
Click to expand...
Make sure you keep the number of the local taxi and car hire firms handy:hysterically_laughi
 
Datatek said:
I have not got time to check at the moment but I think your torque figures are wrong from memory Tony. The box limit is 300Nm, the V8 is below that, the chipped diesel well above it which, along with the lack of torqe reduction on the chipped diesel, is why the boxes fail if the power is used.:)
Click to expand...

As far as i can recall 4.0 litre petrol puts out around 190 BHP and 320 Nm of torque. 24 was used on 4.6 to absorb extra BHP and torque. 4.0 litre V8 H/C engine up to 99 140Kw (187 BHP) Torque 236lbs ft or 320 Nm. Post 99 136 Kw (177 BHP).:)
 
wammers said:
As far as i can recall 4.0 litre petrol puts out around 190 BHP and 320 Nm of torque. 24 was used on 4.6 to absorb extra BHP and torque. 4.0 litre V8 H/C engine up to 99 140Kw (187 BHP) Torque 236lbs ft or 320 Nm. Post 99 136 Kw (177 BHP).:)
Click to expand...
The torque figure I have for the 4.0 is 280Nm, I got the same figure when I Googled it. This would make sense as the HP22 is rated at 300Nm max.
The 4.6 is obviously higher torque than the 4.0 as is the diesel.:)

Doh, it's me confusing Ftlb with Nm.
4.6 is 280Ftlb (380Nm) 4.0 is 236 ftlb (320Nm) HP22 gearbox is 300Ftlb absolute max, 250 recomended. diesel as standard 210Ftlb (280Nm) going up to around 250Ftlb chipped. Hope I've got that right now, lost all my original figures when the old computer crashed.
Langley, I believe Gavbriggs and others have dropped the auto & tranfer boxes on the drive, I think it would be bloody difficult, it's a heavy lump, I have baulked at doing mine with a pit.
Eventually I plan to fit the HP24, the later 065 version is a straight swap using your existing bell housing and torque convertor or an uprated torque convertor from Ashcrofts. Several people have now done this with good results.
 
Last edited:
Datatek said:
The torque figure I have for the 4.0 is 280Nm, I got the same figure when I Googled it. This would make sense as the HP22 is rated at 300Nm max.
The 4.6 is obviously higher torque than the 4.0 as is the diesel.:)

Doh, it's me confusing Ftlb with Nm.
4.6 is 280Ftlb (380Nm) 4.0 is 236 ftlb (320Nm) HP22 gearbox is 300Ftlb absolute max, 250 recomended. diesel as standard 210Ftlb (280Nm) going up to around 250Ftlb chipped. Hope I've got that right now, lost all my original figures when the old computer crashed.
Langley, I believe Gavbriggs and others have dropped the auto & tranfer boxes on the drive, I think it would be bloody difficult, it's a heavy lump, I have baulked at doing mine with a pit.
Eventually I plan to fit the HP24, the later 065 version is a straight swap using your existing bell housing and torque convertor or an uprated torque convertor from Ashcrofts. Several people have now done this with good results.
Click to expand...

If HP22 is rated at 300 lbs ft. That is 406 Nm. You are going to get nowhere near that chipping a diesel. If recommended is 250 lbs ft, that is 338 Nm. Well within the scope of a chipped diesel. If you fit a chip to a P38 diesel with a knackered gearbox then you can expect trouble. But that is the same for all gearboxes. If it's not been serviced and been to the moon and back, it's not a good idea.
 
speedyyellow said:
A P38 as your only vehicle? Brave man!
Click to expand...

Ditto if you discount my Imp and motorbike, I am a consultant and drive all over the country in it - obviously if it becomes unreliable I would be forced to relegate it to weekend plaything - so far (touch wood) just over two years of reliable motoring.
 
That's good hear actually. I can put up with strangeness and unexplained occurrences as long as it doesn't leave me stranded by the side of the road. Sadly I commute via train, my ticket price would pay for an awful lot of P38 maintenance!
 
wammers said:
If HP22 is rated at 300 lbs ft. That is 406 Nm. You are going to get nowhere near that chipping a diesel. If recommended is 250 lbs ft, that is 338 Nm. Well within the scope of a chipped diesel. If you fit a chip to a P38 diesel with a knackered gearbox then you can expect trouble. But that is the same for all gearboxes. If it's not been serviced and been to the moon and back, it's not a good idea.
Click to expand...
The figure I have for the HP22 is 300 but it's Nm according to my ZF page I just found, which is why a chipped diesel knackers it. Chopping between Nm and lbs ft leads to all sorts of confusion.
 
Datatek said:
The figure I have for the HP22 is 300 but it's Nm according to my ZF page I just found, which is why a chipped diesel knackers it. Chopping between Nm and lbs ft leads to all sorts of confusion.
Click to expand...

You would have to ask why, if that is so, Land rover used the HP22 on H/C 4.0 litre petrol engines giving 320 Nm of torque as standard and with 20 or so more BHP than you would get by chipping a diesel. From 99 the 4.0 litre had it's BHP reduced from 187 BHP to 177 BHP. Maybe the torque went down also, but that is more likely to be due to emission fitments than any other reason. I don't have torque values for that derivative. But it is an interesting scenario. Why did they produce thousands of vehicles fitted with a gearbox that they knew would not cope? But i still maintain that driven normally a chipped diesel, if the box has been serviced properly, would be ok. Towing would maybe give problems if you chipped one with a tired box that had been neglected, that point is pretty obvious.
 
You must log in or register to reply here.

Similar threads

T
L322 Gearbox shifting problems
Replies
11
Views
1K
TrustyBib
T
ar1g3
P38A Stall speed monitoring gearbox fault
2 3 4
Replies
64
Views
5K
ar1g3
ar1g3
B
L322 Range Rover l322 gearbox issue
2
Replies
24
Views
3K
rich28uk
rich28uk
K
2005 L322 Transfer Failsafe (3 year problem, still unsolved).
Replies
8
Views
554
Bemble
B
Thornegator
Searching for Gearbox/Transfer case specialists, please.
Replies
5
Views
491
tottot
tottot
Back
Top