david85
Full Access Member
What rear end are you running in the rig with 3.08 gears???
I'm still running the factory original sterling 10.25" rear axle assembly which is theoretically available from factory with 3.08s (though I've yet to see a stock original sterling with 3.08s). When I bought the truck years ago, aftermarket gear cutters like Motive Gear still offered a 3.08 ratio for this differential. I think it came in at $330 delivered to my door. Fuel savings paid off the investment in less than three months since it was (and remains) a long distance highway rig.
However gear cutters have determined most guys want lift kits, and bigger tires. For that, you need lower gears, not taller gears. So 3.08s are not available anymore. Sometimes you can still find an online webstore that shows a listing and price, but if you call them they will tell you the same story - not available anymore. I've even contacted a few suppliers to ask them if there is any plan to start selling them again. Basically, they produce a large run at a time, and only of the ratios they know they can sell in quantity. In their opintion (and mine), 3.08s will never be as popular as 4.10s, 4.11s, or 4.56. 3.33s can sometimes still be found but its not much of a drop from 3.55. Believe me, you're not the first guy to ask me about these gears and I wish I could give you a better answer. It may have changed since I last looked but I doubt it.
The one option you may still have is to find the rear end out of a light duty F250 from the early 1980s. Supposedly those were actually produced in small numbers with a 3.07 ratio dana 61 semi-floater. Its not as strong a differential, and still very rare though.
Anyone with 4wd (or aspirations of 4wd) also need to be aware that only the dana44 front axle is available with 3.07 ratio gears. This is again very rare and since most guys aren't interested in a wheeling rig with tall gears, there is little motivation for aftermarket support. The Dana50 and Dana60 only go down to 3.54. The exception is the low pinion dodge dana61, which is available with 3.07s. Unlike the ford 6.9/7.3IDI equipped trucks, many dodge cummins equipped trucks did come from factory with 3.07s.