Rubicon question

He is going to have to buy a speedo gear from the dealership, according to the ring and pinion gear he already has. I used this link to figure mine out:

I really think its a bad idea not to change the gears with that size tire, might be doable with 3.73 but my jeep had 3.07 with a manual transmission when I went to 33's and it was so bad I didn't drive it until I could buy the gears.

Troy

Oh I totally agree with you about gear changing. My CJ7 has 33's and I'm running 4:10 gears. They are about as high as I'd go with 33's. 4:56 would be a better choice at a minimum for him. Some people have to find out for themselves. He will. It s funny he's a nice guy, he comes to me for advice all the time, but never takes it. Then finds out later I was right.... Go figure. You can lead a horse to water, but making him drink is his own decision, eventually he'll get thirsty though. Rich

Replacing the speedo gear would hold true for any Wrangler except the Rubicon. The Rubicon IIRC uses a tone ring and induction pickup in the t-case for the speedo signal...remember, it uses a different Tcase than the standard Wrangler. Hence, the computer probably *will* have to be recalibrated. Or you can get a Superlift TruSpeed speedo recalibration unit, but I think a trip to the dealer will probably be less expensive.

O crap I wasn't thinking when I saw the RUBICON part, lol. He's running

Troy

Good info Matt... I didn't know that...

JimG

All Rubicons have 4.10's. 35's won't be too bad, 5th gear will lack power, only be good for flat or down hill. I put the speedo gear in my TJ after the gear change... worked great! Very easy to do.

I have 3.73 on my 2000 TJ with 33" and you can really tell it when you get in the mud, or just doing a water crossing. Need to bump mine to 4.10's or

Tom

transmission

He will do the same thing you'd be doing -- switch the gear in the speed sensor.

He ought to be able to find the speed sensor on the output of the tcase in essentially the same place as on your CJ. The sensor spins around because it is mounted on a gear that mates to something inside the tcase. Swap the gear to recalibrate the speed sensor.

There is no need to buyit from the dealership, any speed shop should carry them.

I agree with you, BUT the Rubi comes stock with 4.10 gears anyway, so it may work out okay. I stick to 4.56s if I was doing it, so the 4.10s won't be too bad.

Jeff, the Rubicon 4:1 T- case IIRC doesn't use a speedo gear, it uses an induction pickup sensor on a tone ring inside the case.

I've heard that before too but I can't imagine how it would do that unless there is some kind of sensor, I'd guess a GPS module.

That said, I am skeptical.

No, the Rubicon has no way to self-calibrate its own speedometer. The dealer must reflash the computer but I don't think they have a way to reflash for any tire as large as 35".

And the Rubicon's performance with its 4.10 axle ratio with 35" tires and the 5-speed or 6-speed tranny would absolutely suck big-time. Performance would not be so bad with that combination if it had an automatic though.

Jerry

L.W.(ßill) Hughes III wrote:

That is the combo I'm currently using. While not ideal, I'm not a rock crawler so with the auto trans it is satifactory. There has been nothing that 4LO didn't get me out of.

tw _____________________________________________________________________

"There is a very fine line between 'hobby' and 'mental illness'."

Pronunciation: 'jEp Function: noun Date: 1940

Etymology: from g. p. (G= 'Government' P= '80 > No, the Rubicon has no way to self-calibrate its own speedometer. The

i have 456 with 35's and bought a new speedo gear at the dealer it was only

The computer is capable of being properly calibrated for 35's w/ stock gearing by the dealer's computer too, but it's not possible with numerically higher gear ratios. For what you'd pay them, though, the Dakota solution is probably a better deal overall since if he ever does change gears, he just needs to reprogram it again.

-jd

Rich wrote: