Rear end question??
New User
Joined: Feb 2001
Posts: 5
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Rear end question??
My brother has two Broncos. One is a 77 and the other is a 71. They both have 9 inch rears in them, he thinks the 77 is 4.10 or 4.11 but is not sure about the 71. It came out with a 289 engine. Does anyone know what gearing the 71 cme with? Is it a limited slip? The door jam has the tag, but there is no info written on it. Thanks for any help. Rod
Junior User
Joined: Feb 2001
Posts: 54
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Rear end question??
As a general rule most V8's had 3.56:1 gears and 6's had 4.11:1. There were optional ratios that went from 3.56 to I think 4.56. But so far every bronco I have built followed the above rule. The best way to find out is to look at the tags on the axles, if they are still there. They will be held on by one of the nuts holding the Third member in. If it has a "Trac-Loc" there will be an "L" in the ratio such as: "3.5L" for 3.56 or 4.1L. The L may be after the first number, I can't remember. If there is no "L" then it is probably an open carrier.
Junior User
Joined: Dec 2000
Posts: 80
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From: Lakewood, CO
Rear end question??
If all else fails, Jack up the rear with tires blocked and plenty of jackstands, put the tranny in neutral, mark the driveshaft with a white marker, and have a friend spin the rear tire exactly one complete revolution. Count the number of times the driveshaft spins around, and you have your answer.
