Rear End Ratio (1 Viewer)

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Oh...Durka Durka Durka.
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Welcome.


Stock would be 4.11



Good luck!


-Steve
 
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The standard Land Cruiser differential ratio was 4.11 from 1955 to 1978, but it was not the only one available. On very early FJ45's (pre-1967), 3.70's were available as an option, and on FJ25's and pre-1965 FJ40's, 3.36's were also an option, albeit an incredibly rare one. In 1979 3.70's were introduced, on FJ40's and FJ55's until 8/80, when the FJ60 replaced trhe FJ55. 3.70's continued in US-spec FJ40's until the end of production 8/83.
This is a formula to help figure out what r&p you have.
mph x gear ratio x trans ratio x 336 ÷ Tire Diameter = RPM Tire Diameter
Example:
70 mph x 3.73 (gear ratio) x .67 (trans ratio) x 336 ÷ 27(tire diameter) = 2176RPM
70 mph with a 3.73 ring and pinion over drive transmission in 4th gear with a 27" tire will perform at 2176 RPM
Another way to determine your r&p ratio is to place transmission in neutral and elevate one tire. Mark tire and driveshaft, turn tire two complete revolutions while counting number of turns of the driveshaft. This is your Actual Gear Ratio. i.e. 3 turns + 3.00 ratio, 4.1 turns = 4.1 ratio, etc.
Hope that helps!
 
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Since we're talking gear ratio trivia... There were also 3.70:1 diffs available in some years of FJ55s. Coarse spline pinions. I've had a couple of these go through my hands. Can't remember which rig they came out of (I was breaking down a few of them at the time), but I'm pretty sure they were pre-'76.


Mark...
 
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PabloCruise said:
What transmission are we talking here?


That was an example calculation he plagiarized from another site. The only transmission I can think of at the moment has a 0.67 final ratio is a 200-4R.
I think I've seen somewhere some dodge stuff that uses the same.


The 700-R4 is, if I remember correctly 0.70 and most NV4500's are 0.73.

To get some fast easy RPM numbers there are several online calculators:
http://www.csgnetwork.com/multirpmcalc.html
 

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