So the time has come to upgrade. I'll be moving from 295's to 35's. I'm still running my stock gears and I guess my question is do I need to regear? She is has been my DD for the past 2 years however, after upgrade she will become my weekend ride. I have a 08 JKU with 2.5 Pro Comp lift, superchips flashpaq and aFe CAI. Any and all suggestions are welcome. Thanks in advance.

 

Do you need to.... No. Should you...... Yes.

 

Need to??? Kind of I do have to have tires. My 295 KO's only have about 20% left.

 

I think he is referring to whether you need to regear...

 

Auto or manuel? 3.21 or 3.73?

 

Auto. 3.73

 

I ran 33's on my 3.73's and an auto trans for years. I could get from Denver to the Eisenhower Tunnel at 65 mph but I did run it in Drive 2 at 5500 rpm's and had to keep the momentum up to do that.

35's would turn my 3.73's into an unacceptable dog. If you have to go 35's then you need to re gear. And re gearing is darned expensive.

Do some homework on some charts and see what you can live with. If you are going to re gear you should make it worthwhile. So I would think 4.56 minimum to 4.88. It is all a matter of gas mileage in the end. You go 5.56 and it will run fine, top out under 75 mph and suck gas.

It is all a trade off.

 

Only you can decide if you 'need' to regear.

Get the 35's and drive it. When you see just how gutless it is on the freeway, you will reach down and press the OD Off button, and find that the rpm's come up to a more usable level.

Then you can open the faq's and find the rpm charts, and start plugging numbers in. (divide the rpm by .69 to get od off rpm's). You just might find that the rpm's for a 3.8 auto with 3.73's and 35's and OD Off is pretty darn close to a 3.8 auto with 35's and 5.38's with OD ON.

And then you can search and read through about a thousand other threads asking the exact same question. You will find a fairly large percentage of people will suggest that you regear to 5.13's. (though there will of course be a few that will recommend 4.88 or 4.56, and even a few that will recommend that you replace the front d30 with a d44 so you can run 5.38... )



Anyway, going od off will help on the freeway until you get sick of the lack of power and spend the money for new gears.

 

Thanks that helps a ton. One last question, I've been told I need to reinforce the C's and Gussets with going to 35's. Is this true?

 

Depends...

You won't know if you actually need gussets (or sleeves/truss) until after you find out the C's (or housing) are already bent.

That's why you will see the 'cheap insurance' statement used so often when talking about gussets - just because no one can actually tell you whether you will or won't have any problems. (Many people run bigger tires offroad and never have a problem, others have bent c's or broken the front housing just hitting potholes or curbs while running stock tires onroad).

Maybe your best bet is to check around for prices on the various options and then talk to a few shops to get labor rates. And while you're there, also get an idea on the cost to fix a problem after the fact --> offset balljoints + labor to 'fix' bent C's (and then the gussets + labor to keep them from bending further), or, gut the housing and straighten bent tubes (and then sleeves/truss + labor to keep it from bending again).

That way you can make a more informed decision on which housing upgrade(s), if any, are right for you. (don't know about you, but actually comparing the numbers side by side helps me make decisions. Ya know, since the C's are fairly well known to be on the weak side, $150 for a gusset install now makes more sense to me than the 'chance' of $800 for offsets + gussets later)