BroncoII4x4.com

I have a 1986 Bronco II and I was told the rear axle would eventually need replaced. At one point, I bought an '85 BII for a transmission swap. Is there any difference in the rear ends from '85 to '86 (i.e, gear ratio or something) that might be of benefit to me or is there another year of BII I should be seeking out for a better gear ratio? I commute in my ride (120 miles round trip, 5 days a week) but I ain't afraid to take it out on the weekends and tear up the trails so I want something that is ideal for said situations.

Thanks!!!

If you change the rear gear ratio you'll need to change the front to match it. As for as the ratio goes 3:43 is a common ratio as is the 3:73 the 4:10 is a little tougher to find but there are some flaoting around. The 3:43 will be better for fuel economy as long as your on fairly flat ground and not pulling/hauling much weight. You need to check your ID tag on your rear end to see what ratio you have. There's a code in the door jam that tells what it came with, but it may have been changed at some point in time.

Here's a small chart with codes for the ratio

Bronco II
42 Regular 2640 3.45
44 Regular 2640 3.73
47 Regular 2500 4.10

D2 Limited Slip 2500 3.45
D4 Limited Slip 2640 3.73
D7 Limited Slip 2500 4.10