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Rear Axle Ratio?

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Bruno_69z28

Senior Member
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I'm looking at buying a used TR4 rear end. Is there a way of telling the ratio without taking it apart? I turned the axle one revolution and the pinion turned aprox two revolutions.

Bill
 
Well, if you could be sure that you're looking at an original and undisturbed unit, you could check the serial number: CTC prefix for for 3.7:1; BTC for 4.1:1.

Barring that, try turning both axles (or flanges or drums) in the same direction at the same time, and then count the number of turns of the input flange. You need to do it that way due to the "differential" action.
 
Thanks Andy,
I can't find the numbers on top of the rear end (as shown in the Bentley manual). Is there another area where they might put the numbers?

Thanks again,
Bill
 
[ QUOTE ]
...I turned the axle one revolution and the pinion turned aprox two revolutions...

[/ QUOTE ]

Sounds like only one side was turning so the pinion would have turned either 1.85 or 2.05 revs. Okay, those are both about 2.

Use a bit of tape and a clear mark and try again. You might try turning it 10 times and counts the number of times the mark goes by -- 18.5 or 20.5 -- to be sure what you're seeing.
 
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