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Discussion Starter #1
Hello,

Are there differences between the gearboxes and the differentials of the versions (1300,1600,2000 etc) of the GT (different ratio, and gears)?

I have a 1972 GT 1300 Junior and I don't know what gearbox and differential it has on it.
Can anyone help me find out? Are there any codes on the gearboxes?

Thank You!
 

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Hi Stephan,
1300 JRs gearboxes have a shorter 5th gear; 0.87 vs 0.79 for the other engined models. First through fourth are the same. As for the differential, it is most likely a 41/9 (4.56) ratio non-limited slip.
 

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Discussion Starter #3
Gearbox and differential identification.

Thank You sir,
Is there a way to identify my gearbox and differential?
I am asking because I restored the car to it's original 1300 engine.
It had a 1800 alfetta engine when I bought it and I don't know if they changed gearbox and differential as well.

Thank You!
 

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Thank You sir,
Is there a way to identify my gearbox and differential?
I am asking because I restored the car to it's original 1300 engine.
It had a 1800 alfetta engine when I bought it and I don't know if they changed gearbox and differential as well.

Thank You!
If your box is out of the car you can select 5th and compare the input rotation to the output. 100 turns in gives 87 or 79 out. 10 in gives 8.7 0r 7.9 out.

Same with the axel, hold one wheel end, do a number of turns input and compare to the rotation at the wheel. ( I seem to remember that the wheel count then has to be divided by 2, or was it multiplied by 2) then compute the ratio.

Some times the trans is stamped with a pair of numbers, say 8/43 that indicated the speedo gear's ratio inserted and hence the original axel ratio, I believe.

FWIW

Ken
 
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