I am trying to identify what rear gear ratio ring and pinion are in the A body 8.25 axle in my brother's Duster. The cover tag is long gone.

The following numbers are stamped into the outer face of the ring gear in this order:

Pentastar
3723584
245
1074
PP
MS
291
HT01
HelixForm3

I figure the 3723584 number is the only one long enough to be a Chrysler part number, ut it doesn't match any 8.25 gearset listed in my 1974 factory parts book. That means that this rear axle must be form some other year a-body. 73, 75, or 76.

I know that Chrysler also stamped the ratio of the gearset into the outer face of the ring gear. If I am reading the numbers right, that means that the gears I have in this axle are either 2.45:1 or 2.91:1. I can live with 2.91:1 gears, but if it is a 2.45:1 I will switch the gears out to the 3.2 gears I have.

Can anyone either (a) check the part number and tell me what gearset I have or (b) tell me if the gears are 2.45 or 2.91:1?

Thanks!

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Casually looking for a Clifford hyperpak intake for cheap.

Pictures, if they help any.

_________________
Casually looking for a Clifford hyperpak intake for cheap.

Count the teeth and divide............

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

Yeah, but that pinion gear is way back in there and hard to count accurately. I was hoping for a cleaner and easier solution. I am going back out now to see if the ratio is stamped anywhere on the housing.

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Casually looking for a Clifford hyperpak intake for cheap.

49 ring teeth / 22 pinion teeth = 2.22727273

Looks like it is a 2.2:1 ratio axle after all.

I am still curious as to why 2.2 is not stamped somewhere on the edge of the ring gear.

_________________
Casually looking for a Clifford hyperpak intake for cheap.

Never heard of a 2.2

If so, you're screwed......


"From what i understand there is no way to modify the 2.2 or 2.45 carrier. You have to change out the carrier for one that has 2.56 or higher gears. that is why I will look for a 96 or older at a U-pull it."

Bottom of this thread by bill55az 04-21-2011, 08:38 PM

http://www.aspenandvolare.com/archive/i ... 903616e713

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

Right, that is why I got the carrier for the 3.2 gears when I bought the gears. I purchased everything out of the center section of the axle.

_________________
Casually looking for a Clifford hyperpak intake for cheap.

2.2:1 was the "economy"/CAFE compliance attempt option for axles in V-8 powered cars.

_________________
Casually looking for a Clifford hyperpak intake for cheap.