Patrol Diffs

It's an off roader only, so engineering isn't an issue. As long as the pinions are parallel I wouldn't think it matters what angle the drive shaft is on. Whether it's in line or offset, the pinions are parallel.

The A frame issue I think I can overcome by fabricating a bracket. I was thinking of using a swivel joint there rather than the original ball joint anyway for clearance.

I know the ratios are different, hence another plus for doing the swap. Having 33's I need lower diff gears so going from 3.54 to 4.11's is good.

If the output shaft yoke is not in line with the Pinion Yoke then you have to add the angles of the UJs both horizontally and vertically when calculating UJ angularity.
The yokes are only parallel at one moment at rest, when the car is moving the angles will move all over the place and the UJ angles will change constantly.
That is why they vibrate.
One question I have is why not fit a Toyota diff centre and axles if your concern is breaking diffs. There is even a template floating around somewhere on this forum to redrill the holes in the axle housing.
Have you considered the cost of new /altered driveshafts, which you will also suffer with Toyota diffs I guess.
BTW , The breaking of diffs is directly related to driving style with Rover diffs. The fault of the 2 planetary diffs is that the cross shaft starts to spin and picks up and I will put it in BOLD capitals IF YOU CONTINUALLY SPIN ONE WHEEL .
IMHO there could be a simple fix for this and that is to add a grubscrew to the hemishere that locks the pin in place in addition to the infamous circlip. BUT the major factor in Diff breakage is driving style, less spin more diff life.
Regards Philip A

Yes, I realise that and I do have an aggressive driving style, but I bought a 4WD to do 4WDing, not to drive around obstacles.

The first diff smashed the spider gears and snapped had cross shaft. It was a direct result of a heavy right foot in the exact circumstance that you have put in bold. The second diff snapped an axle and broke teeth on the spider gears, but I was actually crawling pretty slowly up a hill and it just popped when I came to a rock. No wheel spin that time. The third diff did spider and the crown wheel on the same hill.

My aim is to modify this car to handle what I throw it at. I'm not going to baby it because of the weaknesses it has but rather eliminate those weaknesses. It's not a tourer, it's not a daily. It's an off road toy and thats it.

Just to add to Philip A's wise advice;) I sense that you are a little bit swayed by 2 issues: (a) you're convinced that GQ diffs are very strong (they are, in the application for which they're used) and (b) you can obtain them at what you consider is a good price. Coupled with this, is access to what appears to be a well equipped workshop, so the potential engineering fab. issues are seemingly discounted. But you haven't fully explored the engineering theory and practice... which ultimately could be the major failure point for you.

The GQ diff is an integral part of a "systems engineered" package i.e. the GQ Patrol. In that package it does its job very well. Extracting the component and applying it to a different package without due consideration of the new design constraints in a Land Rover is a good way to potentially spend several thousand dollars onlyto prove the wisdom of what knowledgable folk have posted already!

Could I suggest you take a bit of time to look at this Youtube clip which explains Land Rover diffs, how to peg them to increase their strength etc ... It may assist your quest for improved performance consistent with modified driving style. Good luck with it;)

[ame=http://www.youtube.com/watch?v=kF_spN8QNmc]Land Rover Pegged Differentials HD 4 Pin Diff Pegging WHY things break & Some Options - YouTube[/ame]

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Originally Posted by Not_An_Abba_Fan

Yes, I realise that and I do have an aggressive driving style, but I bought a 4WD to do 4WDing, not to drive around obstacles.

The first diff smashed the spider gears and snapped had cross shaft. It was a direct result of a heavy right foot in the exact circumstance that you have put in bold. The second diff snapped an axle and broke teeth on the spider gears, but I was actually crawling pretty slowly up a hill and it just popped when I came to a rock. No wheel spin that time. The third diff did spider and the crown wheel on the same hill.

My aim is to modify this car to handle what I throw it at. I'm not going to baby it because of the weaknesses it has but rather eliminate those weaknesses. It's not a tourer, it's not a daily. It's an off road toy and thats it.

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with all respect... hope you have full and deep pockets to realise your dream:D There are regular series of 4wd off road races in which owners /sponsors invest upwards of half a mil. dollars in design mods, specialised parts etc in the quest to build a machine that takes what they can throw at it... and they break down and get beaten usually by those who understand how to extract optimum performance within the design limits of the vehicle and drive accordingly... :angel::wasntme:

I reckon if they're your constraints, then absolutely go for it. The Patrol axles are good. There will be a driveline solution somewhere, even if it comes to double DC joints or using CV's like Pete Antunac in his massive crawling beast. I'm keen to see how you bring it all together.

You didn't say it was an only off-road car. That makes it a lot easier! If you don't have to worry about engineering it, then just go for it. You will simply find that there will be a continual line of hurdles to get past and you'll just have to work through each one. Since you've got the workshop to handle it, you shouldn't have too much trouble. Trouble with these things usually comes from people not considering legalities or trying to do the job at home without the gear.

Even on the road, I doubt an engineer will have any problems with signing off on it assuming the workmanship and engineering in the conversion is sound. The only issue in reality is the tailshaft angles and I dont think that will be a big one. Other than that, the axles are wider, stronger and stop better, so assuming the brakes work well, the tyres are covered, the speedo is accurate and the fabrication good then it will probably be approved like any other conversion.

What brake setup does your rangie have? If it has the twin brake line per front caliper then you're going to need to figure out how to make it stop too. The range rover brake setup is very different to a GQ patrol.

Question: if you want a car to do this, why not just buy a GQ patrol? Or a 80 series cruiser? It'll be cheaper and easier in the long run. Or if you want an off road toy only, build a comp truck properly. I have a 2 door rangie, 35s, maxi drive and mcnamara diffs, bar work and a winch.. it goes pretty good but its no comp truck. I'm a mechanic and an Auto electrician, done all the work myself and however much I love my landy.. if I wanted a serious off road 'toy'... I wouldn't buy another one.

I appreciate all the input. I love my Rangie, I love how it looks and drives. I love the looks I get when it makes it up a hill that others can't make. I also realise it's weaknesses so I'm trying to work around them.
The build itself shouldn't be too difficult, as I said earlier, the main issues that I think will be harder to overcome will be brakes and drive shaft. Yes, mine has two lines per caliper on the front. I'm thinking I can T them together to a single line for the GQ calipers.

Drive shaft I can probably make my own DC, or possibly a double double?