Outer Limits 4x4 Board

Getting some 4.1 centres second hand just wondering
what the tooth count is on the crown wheel so I know
i'm getting the right ones... If I counted right the standard
diff is 46 teeth..

Thanks Jeff

Should be 41 crownwheel and 10 pinion (if a GBR ROVER diff).

Crownwheel tooth count / Pinion tooth count = diff ratio.
4.7:1 ROVER diffs are 47 crownwheel teeth / 10 pinion teeth = 4.7

3.54 diffs must have 13 pinion teeth if your CW tooth count is correct.

So what are your plans?

sorry dont mean to say u are wrong isuzu but that is not always the case


43 and 9 is a common one 4.77 or 4.8 it is usually called (hilux)
41 and 9 are considered a 4.5 diferent manufateres us different tooth counts Which is why it is common for say a patrol 4.1 and a hilux 4.1 to spin at slightly different speeds
the best way to check is to count crown teeth and divide by amount of pinion teeth

cooter wrote:sorry dont mean to say u are wrong isuzu but that is not always the case


43 and 9 is a common one 4.77 or 4.8 it is usually called (hilux)
41 and 9 are considered a 4.5 diferent manufateres us different tooth counts Which is why it is common for say a patrol 4.1 and a hilux 4.1 to spin at slightly different speeds
the best way to check is to count crown teeth and divide by amount of pinion teeth

I assumed the question was about rover diffs. That was right wasn't it jbell???

If you count both sets of teeth you can work out the ratio whatever the diff.

what rover came with 4.1 or are they all after market?

cooter wrote:what rover came with 4.1 or are they all after market?

Aftermarket from GBR, KAM and Maxi-Drive.
Also possibly one of the Rover car (p6B?) ratios but not sure.

I'm pretty sure my Rover type 4.11's have 9 teeth on the pinion and I cant recall for the crownwheel, though its not the 4.1 10/41 combination.

My Toyota 4.1's on the other hand are definately 10 on the pinion and 41 on the crownwheel.

Slunnie wrote:I'm pretty sure my Rover type 4.11's have 9 teeth on the pinion and I cant recall for the crownwheel, though its not the 4.1 10/41 combination.

My Toyota 4.1's on the other hand are definately 10 on the pinion and 41 on the crownwheel.

The 41/10 numbers were for the GBR ring and pinion. KAM or others might be different?

Yes isuzu it is for rover diffs.. Had a look at the 4.1s
& the crownwheel count was 37 teeth. Im not getting
them until I know they are what I want...4.1s.....
Id better go back & count the pinion as well.

Another diff question the 4.7 out of a series 3 how strong
are they??? was it just the axles on the series landys that
were weak??? mainly a salisbury diff question!!!

Ive got a V8 county with 34s but going up to 36s & I want to
get my gearing back on track. Went ok on 34 but 36 would
push it..

cheers Jeff

jbell wrote:Another diff question the 4.7 out of a series 3 how strong
are they??? was it just the axles on the series landys that
were weak??? mainly a salisbury diff question!!!

I assume you are talking about a S3 LWB (109) since you mentioned salisbury diffs...

The rear salisbury 4.7 is extremely strong, I don't know anyone who has broken one. You cannot just swap R&Ps though, you need to swap centres too, as the crownwheel flange is in a different place.

The front is another matter, a rover 4.7 is the weakest rover ratio. I have seen some people get a good life out of them (even on 35's) when they are easy on the right foot and mechanically sympathetic, but the average driver on 36s would probably break a fair few. Again you have to change the diff centre to fit the 4.7 ratio (or use a ring gear spacer from MD or elsewhere).

One option is to use the 4.7:1 ring and pinion made for the 6x6 perentie, which are front-specific and made for the 3.54 carrier, but the list price is $1700 for one ring and pinion!!!

A better option would probably be to put a toyota centre in the front axle, and fit a matching Dana 60 ratio to the salisbury.

Or get a KAM/GBR 4.75 gearset - who knows how strog they really are though?

Im on 36's and 3.54s which is bearable but not ideal.
New car is having 4.5s so should be about right.

A few guys down here who are running 38's are using 4.7s and have broken a few.

Look into what ben said though, Dana rear gear set and a toyota front. That was my original plan, but it wasn't going to be ideal for me.

Dave.

Thanks guys for your replys.. Think Ill look into the dana rear
& toy front idea if the 4.1s arent enough..

Been tooth counting today 3.5=46crown 13pinion
4.1=37 "" 9 """

DaveS3 what centres are you going to use to get 4.5 ?????

cheers Jeff

jbell wrote:Thanks guys for your replys.. Think Ill look into the dana rear
& toy front idea if the 4.1s arent enough..

Been tooth counting today 3.5=46crown 13pinion
4.1=37 "" 9 """

DaveS3 what centres are you going to use to get 4.5 ?????

cheers Jeff

If the diffs have 37 crownwheel teeth and 9 pinion teeth then they are 4.11.

If you go the toy/D60 route you have the choice of 4.1:1 4.3:1, 4.5:1/4.56:1, 4.88:1.

Bundera - but good luck finding one.

I was give 2 good LP 4.5 runner centres are having hell finding one for a reasonable amount of $$$ (Sub 800 )

If any one that reads this has one

DaveS3 wrote:Bundera - but good luck finding one.

I was give 2 good LP 4.5 runner centres are having hell finding one for a reasonable amount of $$$ (Sub 800 )

If any one that reads this has one

Dave, why not run a sals in the rear with 4.56:1 D60 gears?

Getting my sals windened is becoming a PITA, then getting correct hubs to convert to disks ect

getting a spacer for the ring gear, bearings - not sure exactly whats involved.

Its still an option, but there are more custom parts than the toy conversion

Jeff when you guys are talking of using toyota fronts dose this conversion just bolt up if so why not use the diffs out of a Hiace which are 5.29s and are the exact same center as a hilux this is what ive got in the zuk centers bolt straight in to a lux housing nothing to do

The problem with the front is that you need a HP due to the track rod which runs behind the housing. The LP interferes with this.
For the rear, that would be no problem - you would just have to use aftermarket HP gearset (if they even make them? )