What do you this Diff is from

Hi guys
On Saturday on our way to have the 2a MOT,d we notice that the gearing was a bit OTT with having the HRTC and Def 3.54-1 diffs fitted so when we got back i decided to pull the rear diff out and fit one of the old diffs back in and after checking each diff and making sure they wss the right ratio i discovered that one of them was 4.7-1 and the other was 2.3-1 which is a lot higher ratio than the 3.54-1 Def diff i removed and just wondered where or what it was originally from

Are you sure both sides where moving freely when you checked as your numbers suggest 1/2 of 1st test.

I noticed that, was it rather late at night......?

cornish rattler said:

Hi guys
On Saturday on our way to have the 2a MOT,d we notice that the gearing was a bit OTT with having the HRTC and Def 3.54-1 diffs fitted so when we got back i decided to pull the rear diff out and fit one of the old diffs back in and after checking each diff and making sure they wss the right ratio i discovered that one of them was 4.7-1 and the other was 2.3-1 which is a lot higher ratio than the 3.54-1 Def diff i removed and just wondered where or what it was originally from

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This is a bit hard to read. Are you saying you have been running different diff ratios front and rear!!!!!

No such thing as a 2.3:1 as far as I know.

Blackburn said:

Are you sure both sides where moving freely when you checked as your numbers suggest 1/2 of 1st test.

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Yes had half shaft in both sides 1 full rotation of the halfshaft flange to just over 2 rotations of the diff flange

300bhp/ton said:

This is a bit hard to read. Are you saying you have been running different diff ratios front and rear!!!!!


No such thing as a 2.3:1 as far as I know.

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Not me the p.o was but the odd diff ratio diff was in the front and the 4.7-1 diff was in the rear, i fitted 3.54 diffs whilst doing the rebuild inc a 200tdi conversion but found out the gearing was far to high, had an HRTC fitted as well

I don't think you could fit a 2.3:1, the crownwheel would be too small.

If you have the diff out of axle mark crown wheel and turn drive pinion till the crown wheel mark comes back to the same place count the turns of input.
The 4.7 to 1 is the ratio of teeth on crown wheel and teeth on pinion driving it..
If you turn input with halfshafts in you need to see both halfshafts turn the same amount in the same direction.
Try this calculator need to count teeth on pinion which is connected to drive flange expect 10 then teeth on crown wheel think 47.
https://www.differentials.com/technical-help-2/differential-gear-ratio-calculator/

Yes which is the same as with diff on axle rotating the wheel once to 4.7 turns of the diff flange if a 4.7-1 diff, I did do what you said this morning just incase I was doing it wrong and was egzackly the same as me doing it the way I did it
re did as you said with the odd diff out of axle and still got 2.3-1 ratio so just wondered what it was out of really don't think it was out of anything land rover or rover tbh but just

cornish rattler said:

re did as you said with the odd diff out of axle and still got 2.3-1 ratio so just wondered what it was out of really don't think it was out of anything land rover or rover tbh but just

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Something is out of whack here - As Blackburn said in post #8, 10 pinion teeth and 47 crown wheel teeth will produce a 4.7:1 ratio diff ..... now, .... as rob1miles said in post #7, the crown wheel is going to be too small ( to fit the sun and planet carrier etc., inside ) - if the pinion in this diff has the same number of teeth, then to get to 2.3:1, you'll need a 23 tooth crown wheel, which will be tiny given the optimum tooth profile is more or less constant in this application....

Got any pictures of this diff please? I'm curious as to what is going on

Ok will take pic's tomorrow

I know that KAM did a 2.81:1 crown wheel pinion set for the Land Rover diff so it's perfectly feasable that someone produced a 2.3:1 CWP.

Not took pic yet just got up but i remember noticing the sun part of it is a lot smaller than the 3.54-1 diff but the crown wheel looks the same size, can't coment on the 4.71-1 diff as its already fitted.

Citizen Kane said:

I know that KAM did a 2.81:1 crown wheel pinion set for the Land Rover diff so it's perfectly feasable that someone produced a 2.3:1 CWP.

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That would seem incredibly tall gearing though. What would the use be?

Forget my last post its the colour that makes the sun part smaller but here are some pic's, the black diff is the 3.54-1 diff and the silver diff is the 2.3-1 diff

In looks there isn't much diffrence but there is a vast difference in ratio

Look the same to me.

Proof will be in the pudding i supose but as i've just fitted the 4.7-1 diff and knowing the 3.54-1 diff was too high i don't see the point in trying it but will see

tottot said:

Look the same to me.

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+1 - look identical to me too.

@cornish rattler - have you counted the teeth on the crown wheel and pinion in each diff ?