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2014 Jeep Wrangler JK (3.6L Pentastar) Gearing issue


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4 hours ago, M.Seidam said:

Upon instructions from @Veedooshee , see how @Roy Armale Nicly self recovered . 👍

 

@Veedooshee your calmness and ability to deliver prompt and useful instructions is a skill I want to learn from you. Thank you.

Also, thanks a lot for posting this @M.Seidam  because it brings up a very important conversation around a topic that @Brette and I had that day and think might benefit a few people: Gearing Ratios

Apologies in advance for the long post.

@Frederic your input would be very appreciated as a seasoned manual Wrangler driver

To begin, I drive a manual 2014 JK (3.6L Pentastar) with the worst gear ratio (XXXXX Auto said it might be a 3.2)

I bought it used 4 months ago with approximately 33 inch tires on it that I don't want to pay to change till they are worn out. This means that I am completely out of the "effective off-roading combination", see attached chart or this site: https://prodigyperformance.com/blog/jeep-wrangler-gear-ratio-calculator/

If you watch the video, you'll notice a lag between the first attempt (jolty, too much engine) and the last as I went into 4-Lo (smooth recovery)

I know that recovery should happen in 4-Lo, no discussion there, but that affects a lot of other things. Look at how easily I was able to follow instructions when the power was "effective" rather jolt the car around. It also affects my clutch. @Veedooshee you might remember the smell of the clutch from my 4-Hi attempt.

This gearing caused me to lose power several times when the convoy lost momentum in soft sand. I would have to switch to 4-Lo every time to get through areas that should be relatively easy. I never thought much of it because most my off-roading has been on rocks and I'm in 4-Lo for all that.

When we got to the last area and went up the steep hill, the same loss of power happened during my first attempt. I did another attempt in 4-Lo and was able go further easily by starting in 3rd gear and moving up as I gathered speed. THIS IS NOT RECOMMENDED FOR AUTOMATIC TRANSMISSIONS OR CARS THAT HAS AUTOMATIC LOCKERS IN 4-LO. @Brette and I debated even trying, but I had read that it is ok on enough forums and we were relatively close to the road.

I spoke to a few garages about re-gearing (which I think I will do) and a few told me not to re-gear, but to start off-roading in the sand on 4-Lo while using higher gears (4-6) instead of 4-Hi in lower gears (mostly 1and 2). Both options remove the strain from the clutch and enables better management of dune inclines and soft sand, but the second option takes much more attention to the drive-shaft. I am still of the opinion that I should re-gear.

If you have reached the end of this post, thank you for your patience. If it is in the wrong place, I can move it to the Wrangler threads. However, I would appreciate any experience or feedback on the situation.

 

InkedJK_GearRatioChart_Roy.jpg

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@Roy Armale my experience is limited to driving manual with my Pajero. From what I am reading, i come to the following points:

1) every recovery should be in 4lo. Switch to low gear as soon as you find yourself stuck. Don’t even attempt in high gear as you’ll be burning your clutch very quickly.

2) 33 inch tyres are not gonna help you, that’s a fact. While they are still in good condition maybe consider selling them second hand. 
 

3) Driving manual gear in the desert requires you to think about your momentum at all times. Mostly you’ll be driving in second gear and sometimes first. The trick is to know when to upshift or downshift. This will come with practice and practice and practice. To me it feels like you’re overthinking too much especially since you don’t have sand off-roading experience yet.

4) Don’t drive in low gear. You might get away with it for a while, but soon your transfer case internals will be overheating. Low gear is meant to recover and off-road very slowly (like rock crawling). Not for anything faster than 20kmh.

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"Go as far as you can see; once you get there, you'll be able to see further."

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OK.  I am glad that this topic has surfaced.  I have avoided it because I don't want to go against every advice that has been given here.  But for the Wrangler we have two versions:  The rubicon and the others.  I don't know which version do you have, but the Rubicon transfer reduces the gearing 4.0:1 and the other (named sport, Sahara, etc) reduces 2.7:1.  Also the gear ratio that comes from factory usually are 3.71 or 4.10.

In my experience in Chile, running the Atacama Raid for days (and talking with my many sand offroaders friends in the north of Chile.  They have Wranglers JK with 3.71 that they use on 4LO all the time when off-roading without any issues. (and we drove all day long for days).  That with 33" tires.  I don't know about the other brands of vehicles, but the Wrangler you can drive on LO for several hours (if it is a sport model) with no issues (I have done it many times).  They recommend that you don't drive faster than 40 MPH when on low, and I hardly go that fast on the dunes.

For the Rubicon it is a different story.  The fact that the transfer reduces 4.0:1 in LOW seriously limits the speed when in low.  

Again, I don't know about the other brands, but the wrangler I know can handle the 4 LO with no issues.  And if your gears are 3.21 even more.

P.S. You will have to be very careful with your temperature.  When you increase the revs for long periods, engine temp goes up.  When you go on 4 LO engine revs go up.  On the other hand, your gearbox can overheat when off-roading on HI, because the oil doesn't circulate fast enough (this is for the wranglers, again)

P.S.2 Ohh but your car is manual, so you don't have the gear box temperature issue.

Edited by Alexander Alcala
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  • 2 months later...

Hi Everyone, 

Reviving this thread after a long period of travel and then a return to Dubai!

I got my gearing and differentials checked, 2 things popped up:

  1. I'm on a 3.71 (not great for 33 inch tires)
  2. I have a clutch-based LSD (wears out in the desert and was causing some of the issues)

So, I've re-geared to 4.56 and swapped the clutch LSD with an e-locker. This has helped a lot with desert driving.

@Frederic the consensus from the Wrangler drivers that I've been talking to around tires is that larger ones help reduce the drag from our differential since the only way to get clearance for that is tire size and not a lift. With the re-gearing, the tire size seems to work and is aligned with the chart that I shared. 

I'll write back once I have more experience and am talking less theoretically!

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It is absolutely true.  I had 35's and now 37's in my jeep.  4.56 has been the solution since the beginning.  The lift is only to create space for the bigger tires, as you said, the clearance is provided solely by the increase size of the tires.  Enjoy your improved ride

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6 hours ago, Roy Armale said:

Hi Everyone, 

Reviving this thread after a long period of travel and then a return to Dubai!

I got my gearing and differentials checked, 2 things popped up:

  1. I'm on a 3.71 (not great for 33 inch tires)
  2. I have a clutch-based LSD (wears out in the desert and was causing some of the issues)

So, I've re-geared to 4.56 and swapped the clutch LSD with an e-locker. This has helped a lot with desert driving.

@Frederic the consensus from the Wrangler drivers that I've been talking to around tires is that larger ones help reduce the drag from our differential since the only way to get clearance for that is tire size and not a lift. With the re-gearing, the tire size seems to work and is aligned with the chart that I shared. 

I'll write back once I have more experience and am talking less theoretically!

Hi @Roy ArmaleHow is the e lockers in the desert? Have you installed it only on the rear or rear and front. My understanding is that it has a ball bearing system which will cause the diff lock to engage only after quarter or half rotation of the wheel once you flip the switch and again disengages and reengages when you go in reverse. Does that cause any issue? Did you consider air or manual lockers as an alternative. Would love to hear more as I was exploring locker installation options as I have no diff lock currently (as it is a sports trim) and the general consensus i got from the online community is to go with air lockers. @Alexander Alcala do you have any recommendation on lockers. 

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12 hours ago, Roy Armale said:

Hi Everyone, 

Reviving this thread after a long period of travel and then a return to Dubai!

I got my gearing and differentials checked, 2 things popped up:

  1. I'm on a 3.71 (not great for 33 inch tires)
  2. I have a clutch-based LSD (wears out in the desert and was causing some of the issues)

So, I've re-geared to 4.56 and swapped the clutch LSD with an e-locker. This has helped a lot with desert driving.

@Frederic the consensus from the Wrangler drivers that I've been talking to around tires is that larger ones help reduce the drag from our differential since the only way to get clearance for that is tire size and not a lift. With the re-gearing, the tire size seems to work and is aligned with the chart that I shared. 

I'll write back once I have more experience and am talking less theoretically!

Hi @Roy Armale

Larger tyres will indeed provide a bit of lift, but i find a lift kit more helpful for that as bigger tyres will now mess with your gearing.

I do not understand your issue with LSD. The rear locker is only being activated in case you get stuck, so why would it wear out prematurely or cause issues ? E-Locker is more helpful for rock crawling where you would engage it more often.

"Go as far as you can see; once you get there, you'll be able to see further."

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13 minutes ago, Frederic said:

Hi @Roy Armale

Larger tyres will indeed provide a bit of lift, but i find a lift kit more helpful for that as bigger tyres will now mess with your gearing.

I do not understand your issue with LSD. The rear locker is only being activated in case you get stuck, so why would it wear out prematurely or cause issues ? E-Locker is more helpful for rock crawling where you would engage it more often.

Hey @Frederic

Lift: The lift kit is better than larger tires. The main benefits of the lift are approach angle, break-over angle, departure angle, and clearance. With an independent suspension, all that applies evenly. However, with a fixed axle, the clearance part does not apply to your differential because it is “under” the springs, so it does not get lifted. For rock-crawling, this is less of an issue because you manage it through articulation, line, avoiding rocks under you where the differential is located. On sand, especially when cross-crossing, you don’t have that option, so wranglers can face differential drag on the sand. Larger tires help with that one aspect.

LSD: nothing against it! My comment was on clutch-based LSD (does not apply to plate or torsion, which are better for desert) because our tires spin a lot in the sand and the LSD will kick in very often and at high speed (anytime the tire speed is not aligned). It will work, but its clutch pack will wear out quickly and affect your diff oil over time. It doesn’t affect your driving experience negatively, just your wallet. I had the option of repairing mine, putting a plate LSD (Yukon) or an e-locker. I decided to experiment with the e-locker.

E-Locker: Helpful on larger dune climbs when you want uninterrupted evenly distributed torque to the tires during the climb. My experience is limited here, but I’ll keep trying out the different options and report back on the “real world” effect.

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6 hours ago, Anoop Nair said:

Hi @Roy ArmaleHow is the e lockers in the desert? Have you installed it only on the rear or rear and front. My understanding is that it has a ball bearing system which will cause the diff lock to engage only after quarter or half rotation of the wheel once you flip the switch and again disengages and reengages when you go in reverse. Does that cause any issue? Did you consider air or manual lockers as an alternative. Would love to hear more as I was exploring locker installation options as I have no diff lock currently (as it is a sports trim) and the general consensus i got from the online community is to go with air lockers. @Alexander Alcala do you have any recommendation on lockers. 

Hey @Anoop Nair 

I’d rather not give any advice till I’ve got more experience and trial. 

What I did:

  1. Have a 2014 sport with a clutch-based LSD that wore out (some models have it, you can check yours with your VIN, it’s called trac-lok, different from BLD which is on most Wranglers)
  2. Considered Yukon LSD, ARB Air Locker, and Eaton-Style E-locker rather than replacing it with another trac-lok.
  3. Saw that Air Lockers work best, but need a big and expensive setup, so decided against it because I’d rather put the money in bypass shocks.
  4. Saw that e-lockers have the issue you mentioned, but has been reduced with the new models. Also, in the sand the effect of the half spin is not as impactful as when you’re stuck on a rock. Plus, I’m a believer in locking when you begin the challenging section, not when you get stuck.
  5. Spoke to some wrangler enthusiasts and ex-racers who agreed on e-locking.
  6. Installed it and now testing with/without in different situations to see how it feels.
  7. Did not put a locker on the front because the Dana 30 diff has a chance failing with a locker when you push it and I don’t find that a risk worth taking.

Keep in mind, this is all research-based and theory. I’m not the right person to give advice, I’m just outlining my process. More experienced Wrangler desert drivers would be better suited to advise.

Edited by Roy Armale
Added point on front locker
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thanks Roy @Roy Armale for the detailed explanation. I am curious to see how the e-lockers work in sand in real life situations, let's wait and see. By the way, do you mind telling me how much was the cost for e locker and how was the quote for the air locker with compressor set up. thanks again 

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