4 pin diff in a RRC rear axle

[reggie]

I've been looking at fitting a Salisbury rear axle on my RRC but I also want to do a ring & pinion change in the future to put my gearing back to normal.

The only problem is that the ring & pinion is £200 more for the Salisbury than the Standard Rover axle.

So now I'm wondering is it worth the effort of doing a disc conversion on the Salisbury & fitting it to then spend an extra £200 on the ring & pinion in the future or just get a 4 pin diff for my standard axle instead? The only reason I was going to change to the Salisbury was for a stronger diff for little money. ( Salisbury £50 + the parts for the disc conversion )

Will a 4 pin diff go straight in the standard RRC axle & what sort of money do they go for?

I'm thinking it may be cheaper & easier in the long run to upgrade my axle already fitted.

[bishbosh]

Four pin diffs go for good money as the racer boys use them. Not sure of exact figures, but a new one from Ashcrofts is er, dunno, they're out of stock!

If it was me I would put an ARB in as it is 4 pin and a locker too. A stock salisbury is stronger than a stock rover axle, but the down side is the diff is HUGE and you loose a fair bit of ground clearance and will need a new rear propshaft.

Yes it is more money, but with the truck you are developing I would wager you'll end up down that road anyhow.

What are you doing about 1/2 shafts?

[RangeyRover]

Some time ago when I was thinking about axles,

I idly wondered if the Dana 60 stuff from the states would fit in the salisbury as they are related axles.

rovertracks fit dana 60 stuff in their axles, so it can be done http://www.rovertracks.com/products/driveline.html

And then if that was/is possible have a look at dana 60 equipment http://www.drivetrainspecialists.com/categ...s/dana/dana-60/

[jules]

My racer has 4 pin front and rear diffs in its Range Rover Classic axles they are stronger but I couldn't tel you exactly how much stronger.

[custom-conversions]

My racer has 4 pin front and rear diffs in its Range Rover Classic axles they are stronger but I couldn't tel you exactly how much stronger.

4-Pins aren't going to be as cheap as you'd like. Everyone would be fiting them if they were.

Just been thinking, How strong is a Series front 4.7:1 Ring & pinion going to be as that will help with the gearing, maybe a bit too much though but you don't need 100mph top speed on 37's anymore! You can afford to drop the gearing a bit.

You can then fit a sailsbury rear from a series in a defender case.

Can you then fit a series R&P to a Range Rover diff centre & peg the diff to reduce the flex? Or is the pinion the weak link? Would this survive some abuse? I know the diff cetre is still a weak link as are the front shafts & CV's, but at leat the rear has been taken care of fairly cheaply.

Does a R&P from a series even fit in the rover case though? I don't know much about the series diffs but know there are some similarities at least. Maybe you have to use the entire series diff???

It might just save you some cash though, but its loads of work instead. Plus loads of potential issues to resolve if what I'm thinking is even possible.

So, Just wondered if its all a waste of time & its better to save up for ARB's & Lockers instead, they are proven to work at least.

I still don't really like the idea of upgrading the rear & leaving the front stock, the rear is a lot easier to work on & replace bits.

The front is a pain, I hate changing CV's & they are probably the next weak link, 24-32 spline front axle, they are the weakest rover made aren't they?

[Disco-Ron]

Crown diffs do them for 350...... i'm sure he'd do 10 or 24 spline whichever you need....

http://www.crowndiffs.co.uk/

http://www.crowndiffs.co.uk/diffs.html#4_pin

[custom-conversions]

Crown diffs do them for 350...... i'm sure he'd do 10 or 24 spline whichever you need....

http://www.crowndiffs.co.uk/

http://www.crowndiffs.co.uk/diffs.html#4_pin

If its going to be £350 for a 4-pin diff your getting close to the cost of buying an ARB locker. If it was my money I'd be paying the little bit extra for a locking diff.

Lots of info on the crown diffs site which is good but no prices.

[jules]

I changed the gearing on my 4.2 auto Classic which had 35's on for Kam R&P 4.7's which is what I had from a previous car.

It was a little low gearing and if I had a chocie I would have gone for 4.1.

I did have twin ARB's and although I never realy needed to push it hard I didn't brake anything but auto's are softer on drive line parts.

[nicks90]

4-Pins aren't going to be as cheap as you'd like. Everyone would be fiting them if they were.

Just been thinking, How strong is a Series front 4.7:1 Ring & pinion going to be as that will help with the gearing, maybe a bit too much though but you don't need 100mph top speed on 37's anymore! You can afford to drop the gearing a bit.

........

Does a R&P from a series even fit in the rover case though? I don't know much about the series diffs but know there are some similarities at least. Maybe you have to use the entire series diff???

.....

So, Just wondered if its all a waste of time & its better to save up for ARB's & Lockers instead, they are proven to work at least.

......

i wouldnt bother with a 4 pin diff - cost far too much money. You can get them on ebay (rebuilt second hand ones) for just over £300 +del which isnt a million miles off a locker.

if you're jumping from standard 29" rangie tyres to 37's - thats a 22% increase in ratio.

swapping in a 4.7 diff in place of a 3.54 is a 25% drop in ratio - so sounds about right!!!

as for fitting a series diff in a rangie axle - cant see why not. It isnt uncommon from series owners to fit 10 spline rangie/disco/90 diffs into their series axle casings to raise the gearing when they fit V8 or tdi engines. So vice versa should also work. But as you say, the r&p is much weaker in a series diff. But fitting the appropriate ARB locker would solve the weak diff dentre and pegging the diff should stop it flexing and prevent failure (maybe).

fitting arbs / peg'd series diffs certainly seems like a cost effective solution to correcting your gearing back to normal and getting all round lockers. But as you say - you move the issue from the diffs to the 10 spline shafts and cv's.........

[lansalot]

I got a 24-spline detroit locker for the rear of my 90 and am delighted with it. Another option... Steve @ Crowndiffs sorted me out nicely.

[reggie]

I got a 24-spline detroit locker for the rear of my 90 and am delighted with it. Another option... Steve @ Crowndiffs sorted me out nicely.

How much?

[custom-conversions]

How much?

Ashcroft sell them for £375 , then you have got to fit it into your diff case as thats only the diff centre.

ARB's are about a £100 or so more expensive.

I'd guess that crowndiffs are similar in price.Looking at £4-500 once fitted in your axle.

None of these bits are cheap, rover axles are expensive to uprate, maybe worth keeping an eye out for some second hand.

Or if the series R&P could be fitted to a 24spline diff centre you might save some cash but make a lot of work for yourself. Just need to find out if its stong enough if the diff is pegged first.

[roybatty666]

I got my detroit and trutrac from Steve at CD built in 24 spline diffs it was £514 and £494 respectively they work awesomely and have yet to have issues using it in such a short wheelbase like people always go on about, no undue unlocking or clunking, yes it pushes a little around a corner (you automatically over steer a little to compensate) which you only feel when you lift off the power to change gear etc

There are side slope issues with a locked rear but as I am no challenge monster the fit and forget nature of these diffs and lack of airlines and all that fit my needs just fine and outweigh their short comings.

Give Steve a call he is a top bloke who will chat to you about your needs etc and see you right, I got a few other bits off him as well.

[lansalot]

How much?

About £550 I think (damn Highland postage, cost for diff itself was £514 as with roy). My diff had blown so that included a rebuilt diff as well. Simple bolt-in operation, couple of new shafts (got the Ashcroft hardened ones, more money) and away. Really pleased with it. Fit and forget

I asked Steve about the short-wheelbase issue, and he said he runs his in an 88" with no problems. I've certainly seen no downside as of yet, but it's still kind-of early days. My vehicle (though road legal) is only used to drive to the trials and sites and the off-road behaviour will likely outweigh any negative on-road in the future.

I like the fit-and-forget nature - no more struggling through the stage before realising the lock wasn't in.

[V8 90 JON]

Ive got a spare 24 spline four pin dif ,want £250 for it if anyones interested?

[FridgeFreezer]

Just skimmed the thread so ignore me if this has been mentioned, but can't you use the 4.7:1 R&P from a Series LWB salisbury back axle?

[custom-conversions]

Just skimmed the thread so ignore me if this has been mentioned, but can't you use the 4.7:1 R&P from a Series LWB salisbury back axle?

The 4.7 Salisbury rear would be ideal, but what do you put up front?

Can you fit a series 4.7 R&P of any description onto a 24spline centre so you can then fit ashcrofts shafts & CV's into a std rover case?

If so is the R&P strong enough if the diff was pegged?

I know the series diffs are reported as being a little weak but wasn't sure if its just because of the 2-pin centre or the R&P that gives way.

If it all works it'll keep the costs down a bit but mean removing a Salisbury diff once or twice. A fun job by all accounts!

[FridgeFreezer]

Pretty sure you can get uprated 4.7:1 Rover R&P's from all the usual places, no idea how strong the stock stuff is on its own/pegged etc. as I don't run Rover diffs.

[bobtail84]

The series 4.7:1 C&P is made of cream cheese so I would advise not to use with anything more than 70hp. Ashcroft 4.11 C&P is good for 35" tyres and brings ratios down to near standard. You can get 4.7 C&P from kam diffs but IMHO the ratio is to low for road use but if just for off road will give a lower, low box.

HTH

Jeff.

[custom-conversions]

The series 4.7:1 C&P is made of cream cheese so I would advise not to use with anything more than 70hp. Ashcroft 4.11 C&P is good for 35" tyres and brings ratios down to near standard. You can get 4.7 C&P from kam diffs but IMHO the ratio is to low for road use but if just for off road will give a lower, low box.

HTH

Jeff.

Okay, worse than the chocolate ones then. Series ring & pinions must be a waste of time. Shame as they aren't expensive or difficult to find but guess thats why Ashcroft & KAM make them!

Ratio wise a 4.7 with 37" tyres seems to work in theory. At 2700 rpm you would be doing 70mph, when a standard Rangie on 29" rubber will be doing 75 mph.

Ashcrofts 4.11 ring & pinion would be doing 70mph at 2350rpm.

[bobtail84]

Ratio wise a 4.7 with 37" tyres seems to work in theory. At 2700 rpm you would be doing 70mph, when a standard Rangie on 29" rubber will be doing 75 mph.

Yep that's about right BUT....

Ashcrofts 4.11 ring & pinion would be doing 70mph at 2350rpm.

I have an LT77 with a torqueflite 727 and ashcroft 4.11 so at 70 mph I'm revving about 1900 rpm in high range but low range is about standard. 5th gear is an over drive and I have Mega Squirt...

Jeff.

[custom-conversions]

Yep that's about right BUT....

I have an LT77 with a torqueflite 727 and ashcroft 4.11 so at 70 mph I'm revving about 1900 rpm in high range but low range is about standard. 5th gear is an over drive and I have Mega Squirt...

Jeff.

I just used the 1.222 X-fer box ratio & a ZF4HP22 auto to figure out the speeds.

I can see the benefits of the 1.003 X-fer box though, I've got a GMC v8 diesel in one of my cars which doesn't like to rev so that box comes in handy.

[bobtail84]

I just used the 1.222 X-fer box ratio & a ZF4HP22 auto to figure out the speeds.

I can see the benefits of the 1.003 X-fer box though, I've got a GMC v8 diesel in one of my cars which doesn't like to rev so that box comes in handy.

If you want another GMC with a plate for LT77 I might know a man and that's why I fitted the 727 as I was going to fit the Jimmy but it to dam heavy.

[TomG]

Another alternative for a 4.75 ratio stronger R&P is Great Basin Rovers in the states. Wasn't a bad deal back when the exchange rate was better. I understand these are now sold through Ashcroft Transmissions.

1.2 ratio transfer box, 37's and about 2400 rpm at 60mph. 4.75 gets your crawl speed down in low 1st for good control - not as much as portals would but a nice compromise.

[custom-conversions]

If you want another GMC with a plate for LT77 I might know a man and that's why I fitted the 727 as I was going to fit the Jimmy but it to dam heavy.

Thanks for the offer but I've already got 2, ones a 6.5 TD, ones a 6.2. They are really heavy & I don't think I'll use them in the off-roader I'm building, Unimog axles & a heavy v8 diesel would be a little too heavy, it would sink.

GMC v8's must be getting on for around 500kg's of cast iron. They are a right pain to fit & move around.

I think I'll be using a 3.1 Isuzu TD instead. Much lighter, more compact & not a bad engine.