Technically speaking given the way a torque converter works the automatic guys actually can run their engines at lower rpms without lugging the engine-- where as you in a manual will have to down shift to increase your mechanical advantage. The real advantage comes when you decide to shift when accelerating or decelerating. That's when your manual gearbox really helps out because you'll shift at point when the car or truck feels better then with the automatic. As you you would be at the mercy of the automated system's programmed shift points. Sure most AT's use some form of simplistic adaptive system where they model their shifting behavior based on your throttle inputs-- that doesn't really help too much when do something like change the tires to a size 5 or 6 inches larger than stock. But on the converse the automatic works better at low rpm and gives you a torque boost.
It is also usually nice that manuals have closer ratio spreads and have more gears which helps to make up for things like changing tires or other modifications.
Personally, I prefer the manual gearbox.
timmy, can you break down in percent time spent on driving in the city, highway, trails? i think that is also important when making this decision. also, please post back your impressions once the gears are in (i am sure you will).
did the dana 30 have any weight in your decision (as far as pinion size concerns etc ...)?
2013 JKUR Billet Silver -> [JKUR - 6 Speed][3.5" MC ARB Lift][35" Nitto Trail Grapplers on 17" RR Satin Black][Yukon 5.13s][MC Front & Rear Bumpers][aFe 3" Hi-Tuck RB exhaust][Warn 10s][sPOD]
Oh yeah, sorry, I put this in my "37" tire upgrade" thread and forgot to repost it over here.Originally Posted by dalearyous
Here's my percentage driving
40% - 0mph-40mph
40% - 40mph-60mph
10% - 60mph-80mph (my sedan makes up any other highway driving as needed)
10% - Off-Road (hopefully this number will increase as I learn the area a bit more)
Great question on the Dana 30! Yep, the Dana 30 did actually weigh into the decision slightly. I've read that 4.88 is really the highest gear you can safely go on a Dana 30 from a strength standpoint. There are people running 5.13's on the Dana 30 front without any issue, but I've seen pictures and the pinion gear suuuuuuure looks small. Knowing that I want to put a supercharger on at some point (if I can stop forking out money for other upgrades first!) I wanted to make sure I had a ring/pinion that could handle the added power. If 4.88 is supposedly the highest recommended, I figured backing off to a 4.56 would give me a nice safe margin if/when the engine has a nice big power bump. The gears and labor are expensive enough that I would be pretty pissed off if I went with 4.88's and then put an SC on and found that I broke the pinion due to too much torque. I purchased Yukon gears, which are supposed to be pretty good, but then I read that basically every "good" gear you purchase for a Jeep these days is all manufactured from the same main supplier (whoever that is, and most likely made in China.) So with that information in mind, it also swayed me to 4.56 to make sure the pinion gear was a little larger.
I'm having a hard time finding a pic I've seen of the difference between 4.56, 4.88 and 5.13 pinions. Here is one though that shows the difference between a 3.07 next to a 4.56 Dana 30 pinion, which certainly shows the dramatic difference in size. You can imagine how much smaller a 4.88 and 5.13 would be.
Here's a pic of a Dana 44 vs Dana 30 of the same gear gear sizing to see how much smaller a Dana 30 is.
Here's a Dana 30 destroyed by 37" tires (not sure what pinion size it was.) The caption of the post was "Yeah, D30 rings and pinions are virtually bullet proof..." (said jokingly in response to someone saying most people don't break D30's.)
2014 Jeep JKU Sahara, Manual - /OlllllllO\ - 4" Metal Cloak lift, 37" Toyo Open Country's on 20" XD Bully Rims, 4.56 Yukon gears, Mopar High Top Fenders, ARB Front Bull Bar Bumper, ARB Rear Bumper, Teraflex HD Tire Carrier, Teraflex Tire Carrier Accessory Mount, Twin Rotopax mount, Hi-Lift Jack mounted on front bumper, Reverse LED work lights, Warn 9.5ti winch, Synergy Drag Link, Trackbar Relocation Bracket, AMP Power Steps, JK1001 Radio, SpiderShade.
I just went from 4.56 on 35's to 37's. Mine is a 13 auto. So far I am happy with the change. My highway rpm is a bit lower for highway cruising which is nice at 75 to 80. As far as on the rocks I really didn't notice any big difference in crawling. I am checking gas milage averages right now. I did the Procal and am checking it against a GPS and some known distances to calibrate it. All in all I am happy with my 37's on 4.56 gears.
Mod, ORE Magnum 44 sleeves and welded C's, RCVshafts, 4.56 gears, Riddler diff covers, JEReel 1350 driveshafts, Evap relocation kit, AEV rear diff skid, JPI transfer case skid, ORE oil pan armor, Advanced Adapters shift cable, RK 3.5 lift with King 2.5 res shocks with adjusters, MB Black Razor 17-8.5 wheels with 37 MTRK's, poison Spyder brawler sliders, in powder coat, PSC front with a Warn Zeon Platinum and PSC BFH rear bumper.PSC Tire carrier. Oh yeah a Cobra75 to squak on.
Sweet Jeep Gunner! Love the color. Glad to hear that you like the 4.56's on 37" tires. My gears finally arrived and I'm scheduled for April 16th for the install. Feels like I'm waiting forever to get these gears in!!! With the 35" tires and the 3.73 gears, the Jeep was drivable and fun. Going to 37" tires, it's still drivable, but it's lost some of the fun factor. I'm having to balance the clutch/gas a lot more, which takes the fun out of it.
Took it off-road this weekend. Stuff the right rear 37" tire and of course it rubbed on the fender ;-) The need for upgrades never stops. Can't believe the price these manufacturers want for flat fenders. I'm toying with the idea of going the cheap route and cutting the stock fenders, then I can also get the shape I want. I figure if I cut them and don't like them, I can pick up lightly used ones on Craigslist for dirt cheap and try again. Naturally I was looking at your flat fenders on your Jeep!
2014 Jeep JKU Sahara, Manual - /OlllllllO\ - 4" Metal Cloak lift, 37" Toyo Open Country's on 20" XD Bully Rims, 4.56 Yukon gears, Mopar High Top Fenders, ARB Front Bull Bar Bumper, ARB Rear Bumper, Teraflex HD Tire Carrier, Teraflex Tire Carrier Accessory Mount, Twin Rotopax mount, Hi-Lift Jack mounted on front bumper, Reverse LED work lights, Warn 9.5ti winch, Synergy Drag Link, Trackbar Relocation Bracket, AMP Power Steps, JK1001 Radio, SpiderShade.
Yes they do cost. But I ended up resting on 2 wheels and my right rear fender on this little spot. All I got was some rash on the fender lip. If I had not had a good solid fender on it I would have banged up a door like my buddy did on the jeep right behind me. It was well worth the bucks.
Mod, ORE Magnum 44 sleeves and welded C's, RCVshafts, 4.56 gears, Riddler diff covers, JEReel 1350 driveshafts, Evap relocation kit, AEV rear diff skid, JPI transfer case skid, ORE oil pan armor, Advanced Adapters shift cable, RK 3.5 lift with King 2.5 res shocks with adjusters, MB Black Razor 17-8.5 wheels with 37 MTRK's, poison Spyder brawler sliders, in powder coat, PSC front with a Warn Zeon Platinum and PSC BFH rear bumper.PSC Tire carrier. Oh yeah a Cobra75 to squak on.
Got my new gears installed finally (4.56.) So far, I'm very happy with them. I think 4.56 on 37" match pretty well to the feel of a stock wrangler with the tow package (ie. 3.73 gearing.) I do think that I could have gone with 4.88 gears and I would have been just as happy. I've got a set of 35" studded duratrac tires I run in the winter, so the 4.56 gears will probably work better with the smaller winter tires than what the 4.88 would have.
Gas mileage on the way home from the shop was round 19mpg at around 60mph. I was able to cruise in 6th gear at 60mph with some slight hills and it still had enough power for the cruise to handle it, but it's still tall enough that I'm right at 2k RPM @ 60mph and getting good gas mileage.
Just removed the OEM front bumper tonight, the new ARB bumper and winch is going on tomorrow! Temps are forecast at 70 degrees this next week, so it just might be time to go into summer-time mode and get the doors and top off!
2014 Jeep JKU Sahara, Manual - /OlllllllO\ - 4" Metal Cloak lift, 37" Toyo Open Country's on 20" XD Bully Rims, 4.56 Yukon gears, Mopar High Top Fenders, ARB Front Bull Bar Bumper, ARB Rear Bumper, Teraflex HD Tire Carrier, Teraflex Tire Carrier Accessory Mount, Twin Rotopax mount, Hi-Lift Jack mounted on front bumper, Reverse LED work lights, Warn 9.5ti winch, Synergy Drag Link, Trackbar Relocation Bracket, AMP Power Steps, JK1001 Radio, SpiderShade.
The difference between 4.56 and 4.88 is bigger than you think. You made the right choice ESPECIALLY if you want to run duratracs.
I recently bought a 2016 Unlimited, auto-trans. I am having 3.5 superflex lift installed with 37" Toyo MTs. Were you saying that the two members that drove the autos preferred the 4.88 to the 4.56. Thanks. There is just so many different opinions and "experts" on regearing.
Where do you live? mountains? or highways?
If you want to keep your truck a good highway cruiser, go 4.56. If you are looking for maximum crawl, 4.88.
I had 4.88s, and it was too much gear for me as a daily driver. Turned a rocket into a pig. (well not really, but bad enough to change again)
What are your current gears?
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