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Decode Rear End Axle Tube Sticker

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ArizonaBOSS

Because racecar.
Moderator
8,730
2,734
Arizona, USA
The 302Rs were advertised as coming with a 3.55 but many teams used 4.10s.

Easiest way to tell may be to paint pen or tape a line on the driveshaft near the pinion flange then watch the line while turning one of the axles from the outside. You may need a helper to apply some resistance to the other axle.

The driveshaft should rotate 3.55, 3.73, or 4.1 turns for each complete revolution of The axle flange, depending on the gearset (assuming you are loaded with one of these common ratios)
 
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ArizonaBOSS, thanks for your input. Unfortunately the rear end assembly in my 302R is not an original 302R piece. Its from a salvage car of some sort. I've been able to determine that it has 3.73 (based on the nearly illegible diff cover sticker) but I don't know if it has a T Lok or Torsen. I'm building a separate rear end for the 302R chassis and I'd like to list the S215B 2 rear end as being out of "blank" vehicle. I'm trying to determine is it out of a GT500, Boss 302, Track Pack GT, Std GT, etc???
 
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309
Utah
You have probably pulled the cover by now, but here is the trick to determine what differential is in the axle.

Jack up the car set on stands and disengage the e-brake (if present) and rotate one rear tire. If it is a trac loc (posi) the opposite tire will rotate the same way. If it is an open diff it will spin the opposite direction pretty much the same speed. If it is a torsen it will spin the opposite direction, but will hang up a bit. It can be hard to tell the difference between torsen and open wheel using this method.
 
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