Author Topic: 2012 JK  (Read 486 times)

Offline rockman

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Re: 2012 JK
« Reply #6 on: February 04, 2019, 08:34:54 PM »
What size are the tires out of curiosity?
The tires are an inch taller than stock which adds to the issue. The Jeep guys must figure that soccer moms don't have interest in bigger tires. On the other hand, they built the first Rubicon in 03 and it's damn near perfect even with 35s. Different gearing, motor and tranny.

Offline yamaha225

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Re: 2012 JK
« Reply #5 on: February 03, 2019, 10:54:45 AM »
What size are the tires out of curiosity?
'97 TJ, 4 really angry squirrels under the hood, AX-5, 31 MT/R-K's, 44:1 crawl ratio, 8000 Smittybilt X2O winch, Sanden OBA, 2.5 inch RC spring lift, Custom Fab Rear bumper, Ford 8.8 Rear Axle with 4.10's and Trac Lok Limit Slip, Dana 30 Front Axle with 4.10's and a Aussie Locker, Metalcloak Rear Upper Control Arms and Trackbar

Offline rockman

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Re: 2012 JK
« Reply #4 on: February 02, 2019, 09:13:45 PM »
Jeep first used the 6 speed back in 06 for the TJ and it was put in the 4 banger all the way up to the current 3.6. It appears to be the same transmission that works with all ranges of motors and gear ratios and that's part of the problem. The other part is that the new short stroke motors don't have a good bottom end and they need a lower first gear to make up for it. The TJ had a different tranny for the 4 cyl. than the 6cyl. but the JK appears to only have 1 for everything. The highway gears are part of the problem but we'll get good gas mileage on our trip. It will work for us, I'm just disappointed that Jeep didn't design it properly.

Offline yamaha225

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Re: 2012 JK
« Reply #3 on: February 02, 2019, 06:36:37 PM »
While I don't have experience specifically with the 6 speed in the JK, I do have experience with multiple 6 speed manuals. 2 of which were in 2nd gen Tacomas with the 4.0 V6. The Toyota 6 speed has a first gear that's plenty low. The gear spread is as follows:

1st   4.17
2nd   2.19   
3rd   1.49   
4th   1.19   
5th   1.00   
6th   0.85

I've now dealt with Toyotas new 6 speed in the third gen Tacoma that's paired to their new 3.5 V6 which I hate.

The gear spread is actually better in my opinion as it has 2 overdrive gears, however the new engine is anemic under 3000 rpm and makes all its power above that. So having a 0.71 overdrive is great for fuel mileage but you have to downshift all the time. The old 4.0 made lots of grunt down low and you could lug it around in 6th all the time. I think the 4.0 with the new trans would be great.

1st   3.98
2nd   2.02
3rd   1.32
4th   1.00
5th   0.85
6th   0.71

The jeep NSG370 6 speed appears to have the following gear ratios:

1st   4.46
2nd   2.61
3rd   1.72
4th   1.25
5th   1.10
6th   0.84

Without any experience with the 3.6 engine that first gear seems like it would be really nice. I'd wager that a axle gear change to 3.73's would make a world of difference. All three tacomas have had at least 3.70 or deeper axle gears. The third gen actually has 4.30 axle gears.

As for skipping gears I skip them in every 6 speed I've driven, including my Accord with the 3.0 V6 and 6 speed manual. That said, I also will use those same gears in other driving situations. The most common of which is towing with the Tacoma. They're nice to have then.

Good luck with the new rig! We need some pics!
 
 
 
'97 TJ, 4 really angry squirrels under the hood, AX-5, 31 MT/R-K's, 44:1 crawl ratio, 8000 Smittybilt X2O winch, Sanden OBA, 2.5 inch RC spring lift, Custom Fab Rear bumper, Ford 8.8 Rear Axle with 4.10's and Trac Lok Limit Slip, Dana 30 Front Axle with 4.10's and a Aussie Locker, Metalcloak Rear Upper Control Arms and Trackbar

Offline TJKDave

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Re: 2012 JK
« Reply #2 on: February 02, 2019, 04:20:51 PM »
When do the lift and tires get put on?  New gears?
99% of your JK questions answered here thanks to  JLC08JK on JeepForum for this information:

http://www.jeepforum.com/forum/f96/jeep-jk-frequently-asked-questions-will-rub-links-popular-threads-1074059/

Offline rockman

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2012 JK
« Reply #1 on: February 01, 2019, 08:44:21 PM »
About 6 weeks ago we bought Sue a JK Jeep Wrangler that we will take on our trip to Utah. It's a red hardtop with the 3.6 motor, 6 speed stick, 3.21 highway gears and low miles. We enjoy the smooth ride and the way it handles but I'm not impressed with this transmission for this combination. It shifts great but 1st gear is too high and it stalls easily. After that there are too many gears for the powerful 3.6. Also, reverse is located close to 6th gear so whenever you try to jam it into reverse at 50 miles an hour it makes a bad noise. There's no excuse for this fiasco but we're getting used to it. I just skip 1 or 2 gears almost every time and it handles it well. It's really a nice vehicle and maybe I'm just spoiled with the old Rubicon.