[ellman605]

Hey all. My jeep I just picked up has a replaced rear axle with 4.10s in it. Is just a d35 so nothing special. Now I've got 4 inches of lift on there on 33s with a 3 speed auto. Running 70mph almost all day everyday, engines running at 3k rpm.

Here's my question. The front axle is still geared at 3.73. I have the front drive shaft taken off now so I see myself with 3 options. I do NOT plan to go any bigger than 33s for the time being or in the foreseeable future.

1) swap in an hp d30 with 4.10s, and keep the 3k rpm. Be aware, the jeep right now is mostly a highway queen.
2) swap back 3.73s in the rear and leave the front alone. I believe finding a rear axle geared at 3.73 will be much easier than a front axle geared 4.10s down here.
3) just had this thought: basically choose one of the two above, as well as swap in an aw4 from a cherokee. I don't know if this is even a worthwhile option but I figured it might be a decent idea with the prevalence of 4.0 4wd Cherokees down here.

If I remember right, 3.73s would bring my rpm down at highway speeds. I could care less about how long it takes me to get up to speed.

Thanks all opcorn:

 

[larjeep]

Yes. The lower the number the lower the rps.

 

[ellman605]

Does anyone else have any input? The jeep takes off like a corvette and still has a ton of power at 70mph, but I feel the 3k rpm is unnecessary and going back to 3.73s I'd still have power left over, and it'd be less strain on the engine. 4.10s would probably be good with a 4 speed auto, but for a 3 speed?

 

[Black Magic Brakes]

Does anyone else have any input? The jeep takes off like a corvette and still has a ton of power at 70mph, but I feel the 3k rpm is unnecessary and going back to 3.73s I'd still have power left over, and it'd be less strain on the engine. 4.10s would probably be good with a 4 speed auto, but for a 3 speed?

What is the RPM range for 3:73's and 30" tires with the 3 speed which is how the factory delivered so many of them?

I'll give you a hint, it wasn't much lower.

 

[Imped]

Yes. The lower the number the lower the rps.

Well, duh. And what will lower RPM's undoubtedly provide the OP?

 

[UnlimitedLJ04]

Running 70mph almost all day everyday, engines running at 3k rpm.

so?

 

[ellman605]

Looks like the consensus is to stick with 4.10s. Prolly will be easier to find a front axle with 4.10s anyway. Thanks all!