Outer Limits 4x4 Board

I would like to convert my County to 4.77 diffs for a better crawl ratio ( I allready have fairly high ratio transfer gears as the box is ex Range Rover)

Series 3 4.77 Salisbury centers are cheap - can they be fitted to a coil sprung housing? I heard some sort of adaptor plate might be needed - made by Maxidrive?

What about the front diff? would a coarse spine series diff fit the County axles? Its an '85 model, with a 4 speed gearbox

There's got to be a better way, You'll never have confidence in a 4.7 front.

The front centre should be a straight swap if the county is a 10 spline centre. (not sure about the spacer for the rear)

Series centres are 4.7:1, not 4.77:1.

You can fit a 4.7:1 ring and pinion into your existing salisbury housing, but you need to use the 4.7:1 diff centre as well. Or make a make/buy a spacer for the ring gear.

A series 4.7:1 front will bolt straight in, and has the same axle splines as a stock county front (10 spline). But as popeye said, they are weak.

A 4.11 front and a matching Dana 60 gearset for the salisbury would be a better option, or better still a toyota front diff centre and a matching D60 rear ratio.

ISUZUROVER wrote:Series centres are 4.7:1, not 4.77:1.

You can fit a 4.7:1 ring and pinion into your existing salisbury housing, but you need to use the 4.7:1 diff centre as well. Or make a make/buy a spacer for the ring gear.

A series 4.7:1 front will bolt straight in, and has the same axle splines as a stock county front (10 spline). But as popeye said, they are weak.

A 4.11 front and a matching Dana 60 gearset for the salisbury would be a better option, or better still a toyota front diff centre and a matching D60 rear ratio.

I stand corrected on the ratio!

I was going to buy an entire Series 3 rear end swap the centre into my county housing. If I swap the entire center, does this mean I wont need a spacer in the rear?

I know the 4.7 is not as strong in the front but I'm only running 32's and no front locker.........

I'm on a tight budget and this going to be the cheapest way - Series 3 diff =$100, front 4.7 center = $50, also I may be able to sell the 3.54 Salisbury center and come to think of it the front as well to someone who wants to gear up their Series 3!

Mark2 wrote:

ISUZUROVER wrote:Series centres are 4.7:1, not 4.77:1.

You can fit a 4.7:1 ring and pinion into your existing salisbury housing, but you need to use the 4.7:1 diff centre as well. Or make a make/buy a spacer for the ring gear.

A series 4.7:1 front will bolt straight in, and has the same axle splines as a stock county front (10 spline). But as popeye said, they are weak.

A 4.11 front and a matching Dana 60 gearset for the salisbury would be a better option, or better still a toyota front diff centre and a matching D60 rear ratio.

I stand corrected on the ratio!

I was going to buy an entire Series 3 rear end swap the centre into my county housing. If I swap the entire center, does this mean I wont need a spacer in the rear?

I know the 4.7 is not as strong in the front but I'm only running 32's and no front locker.........

I'm on a tight budget and this going to be the cheapest way - Series 3 diff =$100, front 4.7 center = $50, also I may be able to sell the 3.54 Salisbury center and come to think of it the front as well to someone who wants to gear up their Series 3!

If you look - you'll get the series stuff given to you, It normally gets thrown out.

Also you will have to get the pre-loads setup again when you swap salisbury centres. Its not a job for DIY. $$$

Have you worked out Hwy revs with the 4.7 ?

Why do you need to go that slow on a truck that only runs 32's?

With 35's, 4.11's and a County LT230 down a 40deg slope in 1st low I am only doing 1.8kph on the GPS. I could understand it if it was going to be a rockcrawler but geez.

OMG - you want to run 4.7's and 32's!!! I run stock 3.54's on my 3.9D 110 county with 33's and don't have any gearing problems.

The lowest I would run would be 4.1's if it was on 32's and you wanted to do decent highway speeds.

popeye wrote:

Mark2 wrote:

ISUZUROVER wrote:Series centres are 4.7:1, not 4.77:1.

You can fit a 4.7:1 ring and pinion into your existing salisbury housing, but you need to use the 4.7:1 diff centre as well. Or make a make/buy a spacer for the ring gear.

A series 4.7:1 front will bolt straight in, and has the same axle splines as a stock county front (10 spline). But as popeye said, they are weak.

A 4.11 front and a matching Dana 60 gearset for the salisbury would be a better option, or better still a toyota front diff centre and a matching D60 rear ratio.

If you look - you'll get the series stuff given to you, It normally gets thrown out.

Also you will have to get the pre-loads setup again when you swap salisbury centres. Its not a job for DIY. $$$

Have you worked out Hwy revs with the 4.7 ?

At 100kph with my transfer gears (ex rangie) it would be doing 3400 rpm. Standard County is 3100 rpm at 100 km/h. Thats only 300 rpm more.....

I'm finding with the rangie gearbox that it is lacking in on-road performance. I know 4.1's would be ideal but a lot more dollars.....
Andersons in Hervey Bay had a 4BD1 county running 4.7's and 32's. They reckon with the 5 speed box that this was about the ideal ratio. Not sure what transfer gears were in it, I test drove it and thought it went OK.

Mark2 wrote:

popeye wrote:

Mark2 wrote:

ISUZUROVER wrote:Series centres are 4.7:1, not 4.77:1.

You can fit a 4.7:1 ring and pinion into your existing salisbury housing, but you need to use the 4.7:1 diff centre as well. Or make a make/buy a spacer for the ring gear.

A series 4.7:1 front will bolt straight in, and has the same axle splines as a stock county front (10 spline). But as popeye said, they are weak.

A 4.11 front and a matching Dana 60 gearset for the salisbury would be a better option, or better still a toyota front diff centre and a matching D60 rear ratio.

If you look - you'll get the series stuff given to you, It normally gets thrown out.

Also you will have to get the pre-loads setup again when you swap salisbury centres. Its not a job for DIY. $$$

Have you worked out Hwy revs with the 4.7 ?

At 100kph with my transfer gears (ex rangie) it would be doing 3400 rpm. Standard County is 3100 rpm at 100 km/h. Thats only 300 rpm more.....

I'm finding with the rangie gearbox that it is lacking in on-road performance. I know 4.1's would be ideal but a lot more dollars.....
Andersons in Hervey Bay had a 4BD1 county running 4.7's and 32's. They reckon with the 5 speed box that this was about the ideal ratio. Not sure what transfer gears were in it, I test drove it and thought it went OK.

I'll ask Richard tomorrow. When we take the Bushy out on it's maiden voyage.

Mind you, that truck is mostly used for towing so lower gearing is a help.

True, it has a boat behind it most of the time.
Would be keen to hear his thoughts.

Thanks

My 4BD1 powered county with 3.54 diffs, 1.003:1 T-case and LT85 box (0.8:1 5th) has an overall final drive ratio of 2.8:1 in 5th. It happily pulls that ratio on 33's without a turbo. This ratio means about 2700-2800rpm at 100km/h

A 4-speed diesel county (LT95 with 0.998:1 high) has an overall final drive of 3.53:1

With an LT85 and 4.7 diff gears this increases to 3.77:1 and 4.69:1 with an LT95.

To have the same revs at 100km/h as a 4-speed diesel county, you would have to increase the tyre size to 34" for a 5 speed and 42" for a 4-speed.

The 4BD1 in the countys is governed at 3300 AFAIK.

Mark2 wrote: I stand corrected on the ratio!

I was going to buy an entire Series 3 rear end swap the centre into my county housing. If I swap the entire center, does this mean I wont need a spacer in the rear?

I know the 4.7 is not as strong in the front but I'm only running 32's and no front locker.........

If you only have 32's and are easy on it then everything should hold up fine. I have basically the same setup in my IIA, except on 33's. I managed to break one front ring and pinion when I was still on 32's but the new (old) one which has almost no pinion preload has proven to be unbreakable so far.

The front complete centre will bolt straight in. In the rear you will need to put the 4.7:1 pinion into your housing, then bolt the complete centre with ring gear in, and then set up the preload and backlash. This is probably the only expensive part if you cannot set up the diff yourself.

The V8's (mine is a V8)should be a bit more tolerant of higher revs than the diesels.

It still seems like a very cheap way to get a fantastic crawl ratio and much better on-road acceleration albeit at the expense of 400 more rpm at 100 km/h . Plus I could probalbly sell the 3.54 centers for a reasonable amount.

And if I ever track down some overdrive transfer gears it would be be back to nearly where it should be but with the same fantastic crawl ratio (64:1)

Also, lower geared diffs put a lot less strain on the rest of the driveline - gearboxes, transfers, propshafts etc

If you have a V8 then they are a bit happier to rev (if you don't mind the increased fuel bill). Then it should be fine. The high compression V8's should have been fitted with 0.998:1 high range gears, but a lot seem to have been built with 1.1, 1.2 or 1.3:1

You will just need to find a good front 4.7 and go easy on it.