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Jeep Dana 30 axle ratios?
I have a JK Unlimited and it's time to upgrade the axle ratios. I run a 3" lift and 33" tires, mild off-roading, looking for a little more torque, but don't want to go overboard. 3.73 stock is what's in there now, am considering 4.27 or 4.56. What would you all suggest and why? Please, keep in mind that I don't rock crawl, but need to maintain a good highway manners. Thanks!!
P.S. I am leaning toward the 4.56, but bigger or more is not always better. Happy Holidays!!
5 Answers
- JoeyLv 41 decade agoFavorite Answer
You didn't specify if your Jeep is a manual or automatic, it makes a huge difference in the JK because of the difference in the OD transmission ratios .69 in the auto vs. .84 in the manual.
To get your Jeep running in proper range you're going to need really low gears if you have an auto - 4.88:1 should be acceptable - some guys even run 5.13's with the auto - and yes, that is for a daily driver with moderate off road use, not rock crawling.
With the .84 ratio in the manual you can do 4.10's and be good.
These recommendations are for highway driving at 70 mph with 33" tire and should allow for full time use of 6th gear (manual) and 4th gear (OD - auto) and mild to moderate off road/trail use.
- 1 decade ago
I just got 4.56 gears installed on my '98 TJ and I run a 4" lift with 33" tires. Compared to the stock 3.73 I am actually getting slightly better gas mileage on the highway because the engine was having to work so hard before and now I just barely have to touch the gas pedal to go 70 on the interstate. It has gobs of acceleration too! The reason I chose to go with 4.56 gears is because when my 33" tires burn out I am planning to go up to 35" tires. If you are going to stay at 33" tires then I might suggest that you go with the next higher gearing ratio (numerically lower) but if you have thought about throwing a body lift or bigger suspension lift on your JK and 35" tires then 4.56 gears would be a good choice for you!
- Anonymous1 decade ago
I say for the money it cost to upgrade the axles, you could swap in junk yard 1/2 ton chevy axles. There stronger. Unless you plan on ever going high than a 37 inch tire, they will be great choice for long term seeing you like to tinker with your rig.
- 5 years ago
There should be a tag bolted on the cover that has the ratio stamped into it. If the tag is missing you will need to pull the cover. The tooth count is stamped into the side of the ring gear (example 8-28) would be a 3.50:1 ratio. you can also count the # of teeth on the ring and pinion gears, but the pinion gear is hard to see with out pulling the carrier out.
- ?Lv 41 decade ago
Your going to be turning allot of RPM with 33s and 4.56 gearing on highway. Here is a gear calculator to help you with your decision:
