Rear Axle: Determining which diff. I have

[jetboat]

I have 2 diffs. 1 is 59 Hawk V8 stick, the other is unknown. They both have 44 stamped on the lower rite rear,but 1 has a diamond with a C in it, the other has a circle with an A in it. I would like to put my axles out of my 56 pickup in one so I can keep my 5 on 5 bolt pattern??

[StudeRich]

Is the "Track Width" of the "Unknown" one the same as the known '59 Hawk?

The Width of your truck Diff. is wider than a Car Diff. so if one matches your Truck you MAY be good to go.

If they both have Stude. Car width Spring Perch Mounts either will work in a Car, but not a Truck.

Usually THE Most important detail that MUST be known about Diff's. is the Ratio ! That needs to match your Driving Style, Transmission, Engine Power and Weight to be carried in the Truck.

The '59 Hawk Axle should not have been a Model 44 if Original, as '59's had 259 Engines with Model 23 or 27 Axles.

[NCDave51]

And if needing to learn the actual gear ratio, it's as simple as placing the trans in neutral, raising a rear wheel, put a small piece of masking tape on the driveshaft at horizontal, put one at 12:00 on the tire, and turn the wheel until the shaft has made 20 full rotations- counting the wheel rotations as you go.

The ratio is the quotient of 20 divided by (wheel turns). The wheel turns will be some fraction number.

[Mike Van Veghten]

And if needing to learn the actual gear ratio, it's as simple as placing the trans in neutral, raising a rear wheel, put a small piece of masking tape on the driveshaft at horizontal, put one at 12:00 on the tire, and turn the wheel until the shaft has made 20 full rotations- counting the wheel rotations as you go.

The ratio is the quotient of 20 divided by (wheel turns). The wheel turns will be some fraction number.

This does not work with an "open" (non-posi) differential. Doesn't work on a worn out clutch type positraction either..!
Most ring gears have the tooth count stamped on the o.d. Since they aren't in a car, just pull the covers and view the gears.

Mike

[jetboat]

Thanks all, ratio is not a concern except for the low gears in the truck, I was thinking of switching out rear ends in the truck but with the cars being 3 1/2 inches narrower I have a tire rub problem. My 54 3R6 rubs when I corner to hard which I thought was tire size but now I know it has a car diff. In it. The truck being worked on is a 56 ,so I will have to start over.

[Dwight FitzSimons]

I have 2 diffs. 1 is 59 Hawk V8 stick, the other is unknown. They both have 44 stamped on the lower rite rear,but 1 has a diamond with a C in it, the other has a circle with an A in it. I would like to put my axles out of my 56 pickup in one so I can keep my 5 on 5 bolt pattern??

Just FYI:

(1) I assume by "stamped 44" you mean "raised cast-in 44"? On the cast iron housing the "44" won't be stamped in; It will be raised because it was cast in.

(2) The Dana 23/27 is significantly smaller (smaller tubes, smaller housing) than a Dana 44. It is easy to tell them apart side by side.

-Dwight