diff ratio Quest..

[jbell]

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

[ISUZUROVER]

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.

[Suspension Stuff]

So what are your plans?

[cooter]

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

[ISUZUROVER]

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.

[cooter]

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

[ISUZUROVER]

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.

[Slunnie]

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.

[ISUZUROVER]

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?

[jbell]

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

[ISUZUROVER]

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.

[DaveS3]

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.

[jbell]

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

[ISUZUROVER]

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.

[DaveS3]

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

[ISUZUROVER]

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?

[DaveS3]

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

[duncan]

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

[DaveS3]

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? )