FE-FC Holden Discussion Forum

Technical Board => General Technical => Topic started by: Not Happy Jan on April 24, 2017, 02:04:23 PM



Title: Diff ratio
Post by: Not Happy Jan on April 24, 2017, 02:04:23 PM
How do you workout what the ratio's are in a diff?
Nick


Title: Re: Diff ratio
Post by: mcl1959 on April 24, 2017, 04:11:52 PM
Do you mean by looking at it or by testing it.
All Holden diffs except 3.89 have the ratio stamped on the flange where the Uni is bolted on.
So if there is nothing on the flange, it's a 3.89:1 ratio.
You can test it manually (fairly roughly) by counting number of turns of axle compared to tailshaft. Ie, turn the tailshaft around 10 times and count how many times the axle turns. Divide your answer by 10.

Ken


Title: Re: Diff ratio
Post by: FCRB26 on April 24, 2017, 05:52:12 PM
 3.89 will have a Key way and 4 bolts holding the tailshaft on
3.55 3.36 have all short nuts and bolts the whole way around
2.78 and 3.08 have a long drain bolt and the next bolt up is a long one too.

And like ken said its written on the dust cover and the pinion wheel.


Title: Re: Diff ratio
Post by: Errol62 on April 24, 2017, 07:01:31 PM
Count the number of teeth and divide crown wheel by pinion.


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