Need help shopping for new gears

[bobthetj03]

That was the first thing I changed on my TJ. The PO had 33" E rated Toyo MTs on 17" rims. Those tires were so loud and the ride was pretty awful. I found a set of TJ MOABs on CL and got 32" Duratracs. Big difference in ride quality and noise level. You'll like those KO2s. I hope the 50-60 vibes go away with your new tires.

If they do, I could almost live with the 65+, almost. I also took advantage of some free shipping and ordered the last 2 rear lower arms which will complete my control arms selection. I don't expect this addition to change anything in the vibe department.

 

[LCL-Dead]

What kind of monster did I unleash on the forum?! Jebus.. Sorry @Chris, haha.

So I had to drive to Raleigh today and I had to take the Jeep because the wife needed our van for kid stuff. This is the first time I've willingly taken it up over 65mph since I installed the lift and tires (Flipping OD off for me is a legit habit at this point, something I learned from this forum).

I kept OD off up to 70, then turned it back on and pushed it a bit further up to 75 (of course, without a current speedometer calibration I'm sure I was closer to 82-84mph) and then set the cruise control to see if OD would kick on. Now I get what was meant when "hunting for OD" was mentioned back on Page 1 of this thread. I hunted around the speedometer for about 5 minutes trying to get it to shift into the OD gear before throwing in the towel and dropping it back down to 63 with the OD off, keeping the RPMs for the trip at around 2750-2800.

Overall it did well, but I'll be throwing up another thread with a little video I took when I got home to see if someone can tell me what I broke. Poor girl hasn't seen sustained speeds/road time like that since I brought down to NC from Maryland.

 

[Chris]

What kind of monster did I unleash on the forum?! Jebus.. Sorry @Chris, haha.

Don't worry, you're always going to run into the folks who like to tell themselves they don't need to re-gear. It's probably a 1 to 500 ratio, something like that.

But, for those of us who have experienced a before and after re-gear, the difference is night and day. I have no idea why you wouldn't want to re-gear. I've done it twice now and would do it all over again in a heart beat!

 

[AndyG]

Don't worry, you're always going to run into the folks who like to tell themselves they don't need to re-gear. It's probably a 1 to 500 ratio, something like that.

But, for those of us who have experienced a before and after re-gear, the difference is night and day. I have no idea why you wouldn't want to re-gear. I've done it twice now and would do it all over again in a heart beat!

It's like sex . Do it once , and you will want to again . And again .

I really sense the ones that dont regear are normally those that bought the jeep set up wrong ..because if you bought one and slapped a lift and 35's on it , you would know the first test drive that things really changed for the worse.

A 4.0 , of all engines , (legend that it is ) , is like all small to mid bore in line engines , it just doesn't make enough massive power and torque all over to pull big tires if the gearing is stock ...it is awesome down low to mid and fine on top , but all that good stuff goes out the window fast when you increase tire size.

And gearing isn't some exclusive club here , it's done all over the world , especially on competition and modified vehicles , including motorcycles (change sprockets )

 

[Rob5589]

I say it all the time: people skip gear swaps and talk themselves into poor performance because a re-gear is expensive and they have nothing to "show" for it. People complain about 1800 for a gear swap but will run 2k in wheels and tires. You can see the money put into wheels and tires but not into gearing.

 

[LCL-Dead]

One last quick question to reignite the thread:

Switching from 4.10s to 4.88/5.13 (Still undecided between the two), how is this going to affect daily driving in 1-3rd gear on the auto? This thing is my DD to/from work (13 miles, mostly highway). I'm curious how the gearing will affect the lower speed maneuvering/response.

 

[AndyG]

One last quick question to reignite the thread:

Switching from 4.10s to 4.88/5.13 (Still undecided between the two), how is this going to affect daily driving in 1-3rd gear on the auto? This thing is my DD to/from work (13 miles, mostly highway). I'm curious how the gearing will affect the lower speed maneuvering/response.

basically you're going to do everything you're doing right now with more power and less pedal.

You will shift less if it's a manual.

you will be able to pass cars and contend with traffic like you never have.

it really won't change the handling but you will get noticeably better acceleration.

You will feel like you slept in a Holiday inn last night.

 

[Jerry Bransford]

One last quick question to reignite the thread:

Switching from 4.10s to 4.88/5.13 (Still undecided between the two), how is this going to affect daily driving in 1-3rd gear on the auto? This thing is my DD to/from work (13 miles, mostly highway). I'm curious how the gearing will affect the lower speed maneuvering/response.

Don't be undecided on the 4.88 vs. 5.13, don't even CONSIDER 4.88. Your engine and especially your transmission will be much happier with the 5.13. Don't worry about the 5.13 at all, those who regeared to 5.13 with 33" tires loved it. 5.38 is barely enough for my 35's, I wish I could have gone even deeper than 5.38.

 

[AndyG]

I don't have 35 inch tires but I have enough experience changing gear ratios out to tell you to listen to Jerry... A gear job is a pretty good chunk of change and you might as well get the maximum benefit.

Anyway you slice it, and I know it is a fantastic power plant, a 4.0 engine is just not that big. it's great for a 3000 pound Jeep but if you're going to put big tires on it, you've got to compensate.

Jerry and I are not in cahoots... I would not associate with anyone that would be friends with someone like me.

 

[LCL-Dead]

Don't be undecided on the 4.88 vs. 5.13, don't even CONSIDER 4.88. Your engine and especially your transmission will be much happier with the 5.13. Don't worry about the 5.13 at all, those who regeared to 5.13 with 33" tires loved it. 5.38 is barely enough for my 35's, I wish I could have gone even deeper than 5.38.

Aye Sir!

 

[A. Paul]

Don't be undecided on the 4.88 vs. 5.13, don't even CONSIDER 4.88. Your engine and especially your transmission will be much happier with the 5.13. Don't worry about the 5.13 at all, those who regeared to 5.13 with 33" tires loved it. 5.38 is barely enough for my 35's, I wish I could have gone even deeper than 5.38.

I seldom hear of anything higher than 5.38s. If anything higher was available, how much deeper gearing would you want?

 

[Sean Allen]

Curious if power adders come into play when choosing your gears? For example if you only drove up in the mountains or pull a camper occasionally, and you had a supercharger or were stroked and had something like 50% more power than stock, could you essentially overcome the fact that you were geared slightly higher (like 4.56 on 35's with a 6spd or 4.88 on an auto) with the extra power the engine is producing? Or does HP not play a role because gear ratio, RPM and tire size will be what they're gonna be mathematically? Id assume you'd have more grunt pulling a grade etc. and might not even notice? Or does it come down to a re-gear being significantly less money than supercharging or stroking in order to achieve the same result, getting up hills with ease.

 

[Jerry Bransford]

I seldom hear of anything higher than 5.38s. If anything higher was available, how much deeper gearing would you want?

5.89 is available for Dana 44 axles but 5.38 is as low of a ratio as is available for the TJ Rubicon's axles when they have the OE Rubicon lockers installed. Incidentally in ratio-speak, 5.89 is a lower ratio than 5.38 is. If I ever replaced my Rubicon lockers with something else I would consider regearing to 5.89.