[bibby]

hey guys i just am wanting to buy a NT diff center which is 3.9 gearing but the person dosent know if its a NT or WT center is there anywhere on the crown gear or something where you can work it out?

[matth27]

Count the teeth on the crown wheel and divide them by the number of teeth on the pinion

[bibby]

There in the housing its kinda hard to count

[atari4x4]

Check the circle spin ratio...

[bibby]

How? Or where??

[killazook]

Ratio is 3.9:1
Jack the car up mark the tyre and the tail shaft spin tail shaft about 3.9 times so roughly 4 tyre should of made 1 revolution not accurate but thats the only other way with taking it out

[bibby]

It is out though

[atari4x4]

is the diff centre out of the housing, if so count the teeth as discribed.... if the diffs are complete but not fitted to the car, do what killa zook said & measure the circle spin ratio by turning the tailshaft & seeing how far the axle turns.

[bibby]

The center is out but the pinion is behind all the crown gears and stuff its okay mine are nt and the ones i bought are wt

[atari4x4]

WTF, i was confused before, now i'm confuddled.

count the teeth on the crown wheel... put a paint mark on the 1st one & start counting, same goes with the pinion.


the pinion gear is the star shaped one below where the hose connects to the top. (it's a vacuum operated GV front diff so ignore the crap)

[fordem]

OR - mark the crown wheel and rotate the input flange - how many revolutions of the input for one revolution of the crown wheel?

[Jazzor]

NT difs have 8mm holes in the flange and WT difs have 10mm holes in the flange MOST of the time (I have heard there is some odd models or people could have swapped flanges). That's how I tell them apart in my spares collection .