Jeep Tech Question

[Ivanite]

Need some help. I'm at the end of upgrades on my Jeep. Now it's time to work on the drive terrain. It's got a 2" lift with 33's and it has a 4.0 in her. I have just about lost the use of 5th on the highway. I'd like to re-gear it. Should I go with 4.10, 4.56, 4.88’s? What do you run? When I re-gear I'm going to put a locker in it. I was thinking about an Aussie. Anyone have one? What about an ARB or E-Locker. What is best do you think? I have also heard of a Super35. Don't really know what that is. Does anyone have it? The Jeep has factory Dana 30 and 35 axles. Will these hold up? I don't really want to do and axle swap. I'm just trying to get 5th gear back and locked up and better crawling ability. Jeep is a 1997 TJ.

Thanks

[LWR2]

I have a 4 inch lift and 33's with my YJ 4.0 and I have 4.10 gears. Really a change from the 3.73 gears.

LWR2

[LWR2]

here is how I found what I wanted.

http://www.grimmjeeper.com/gears.html

LWR2

[LakeJake]

I had a 4.0, lifted 4 inches, with 33's, running 4.10 gears. It could crawl and cruise on the highway just fine.

[dropem]

I'm running 4.88 gears with 37's. I'm thinking you should go with 4.10's.

[LWR2]

When changing tire size, it's hard to get back to exactly where the factory set things. For example, a new Jeep Wrangler might come from the factory with 3.73 gears in the axles and tires that are about 32 inches tall. A popular upgrade is a lift and 37" tall tires. If you wanted to swap out gears to match the tire change, you'd start with a calcluation like this:

Old Gear Ratio × New Tire Size ÷ Old Tire Size = New Gear Ratio.

Plugging in the numbers you end up with:

3.73 × 37 ÷ 32 = 4.31.

Trouble is, nobody makes 4.31 gears for the Jeep axles. You can get 4.10's, 4.56's, 4.88's and 5.13's. So which do you choose? The rule of thumb is that you always round up. The biggest reason you would want to do that is because larger tires are harder to move. Not only are they heavier, they're typically wider so they have a larger contact patch on the pavement and they offer more rolling resistance. It takes more to push it down the road. In this case, you'd pick 4.56 gears to end up with performance that's close to where the factory put it. A lot of people will take it a step farther and go to 4.88 or even 5.13 gears depending on what they want to get out of their Jeep. But 4.56 gears would be the closest to factory performance.

[Birdymon]

That Dana 35 is really weak. Gears will add the leverage it takes to break an axle easier. Lots of info on Jeepforum.com and other forums. I am going to a much stronger axle next. Surprised I havent broken the stocker yet wheeling in Colorado with 35's and a 4.6 stroker motor...

[TimH]

A friend of mine had a 97 TJ, 4.0, automatic, on a 4" lift with 35's. He was running 4.56 gears in his. We used to drive it up to Mason for the Katemcy Rocks events and it handled both highway and crawling very well.

You could probably get away with 4.10 gears just fine on the 33's.

[outlook8]

I would go 4.56 with that setup. I had 4.10s in my old TJ with the 4.0 and 35s and it was fine too. Currently I have a JK with 35s and 4.88s.

Be careful with the lockers, you are going to break your axles. Hell, I had Dana 44s on my TJ and broke the front more than once...

[Brooks]

Scroll to the bottom and enter the ratio of your fifth gear. See what gets you back to where it was stock or a little more RPM.

http://www.csgnetwork.com/multirpmcalc.html

[Rubi513]

I have 35s on my 04 Rubicon. I went from 4.10s to 5.13s. If I had it to do again I probably would have went with 5.38s. However, I have the automatic transmission.

[Ivanite]

That Dana 35 is really weak. Gears will add the leverage it takes to break an axle easier. Lots of info on Jeepforum.com and other forums. I am going to a much stronger axle next. Surprised I havent broken the stocker yet wheeling in Colorado with 35's and a 4.6 stroker motor...

Yea that's what I here. I only do lite trail riding. That's why I was asking about the Super 35 rear axle upgrade. I don't want to spend the money on all new axles.

So are all of you saying just re-gear and forget about a locker?

I have been to the Jeep forums and read alot but I trust the opinion of you guys alot more

[Ivanite]

Here she is by the way....

[jeepntx]

Stay away from the D35. That money is better spent towards a new axle, either a TJ D44 or putting a bracket kit on an 8.8.

My '99 had a 2" and 33's with 3.73 gears. I had zero issues on the highway or the trails, power-wise. But the engine wasn't exactly all stock...

[dropem]

Yea that's what I here. I only do lite trail riding. That's why I was asking about the Super 35 rear axle upgrade. I don't want to spend the money on all new axles.

So are all of you saying just re-gear and forget about a locker?

I have been to the Jeep forums and read alot but I trust the opinion of you guys alot more

I just went with gears and no locker. I only do lite trail riding and mudding as well. I have not had any problems and I'm running a larger tire then you.