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Recommended gearing for Sahara V6 with 3.45 gears on 35s with a rear D44

What gears should I go with on a Sahara V6 on 35s with a rear D44?


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CarbonSteel

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I voted 4.56, but if you have really heavy tires/wheels and/or have added lift kits, skid plates, winch, etc. you should entertain 4.88. The 3.6L is pretty gutless overall all and is impacted more so than the 2.0T or 3.0T when adding all of the things that people do.
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aldo98229

aldo98229

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British Columbia just imposed fuel rationing for the next 11 days as a result of all highways being cutoff with multiple slides and flooding. Private vehicles are limited to 10 gallons per visit; all non-essential travel is prohibited.

I was planning to take the Jeep; we were going to go off-roading up Squamish Valley. I guess that plan’s now off, especially with my 13 MPG.

I think I’ll be taking the Fiat Spider instead; the tank takes only 10 gallons and I can get 30 MPG without even trying.
 

Pismo61

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4.56 maybe 4.88s,8th gear is pretty steep.Id rather over gear a little because you have to take into account the lift height(wind resistance), the added weight of the tires and what ever added weight you have not just the tire size.I learned this in my TJ days.Id keep what you have and just make it better.Mpg wise eh maybe 1-2 better no guarantee there.I only drive 6000 miles a year so I dont care as much about gas prices.Still care but not as much and Im in Ca. 4.70 a gallon average.
 

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4.56 would keep the engine at above 2,000 RPMs, which perhaps explains why XR owners are seeing 15-17 MPG.
With my stock 3.6L/3.46/32"/6MT, I got better fuel economy turning 2500 in 4th gear than I did turning 1700 in 6th. I proved this to myself tank after tank of gas.

After moving to bigger tires, my fuel economy was in the 15-17 range on 3.45 gears, and it's still in the 15-17 range on 4.56 gears. The RPMs I'm turning make far less difference than the size of my contact patch, and the profile I'm presenting to the wind. Plus since I went to 4.56 gears, I also have to expend fuel to go DOWN hills at speed. The final drive ratio is low enough to cause a braking effect that has to be counteracted pretty much at all times, and very little coasting is possible now.

I'd expect the XR to be very similar.
 

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I have a Sahra with a Dana 44 rear, 2.5 Mopar lift and 35" tires. I decided to go with 4.88. I purchased them today, and have them installed soon!
Let me know how it works out!
 

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You're looking at highway performance. So here's what I look at: What speed is the engine turning at 70mph? (I use the grimjeeper calculator)

With factory tires and gears, it's turning 1620 rpm in 8th.

With 35" tires, and factory gears, it drops down to 1484, and, as you've observed either won't shift in or won't hold 8th gear.

So, we want an axle ratio that'll slightly exceed the stock RPM, to give the engine just a little *more* power in top gear, to compensate for the increased rolling resistance and wind resistance.

4.10 takes you up to 1763. That might be enough, although you sometimes hear of Rubicon owners who also gripe that it won't stay in 8th with 35s.

4.30 goes up to 1849 RPM - 200 higher than factory.

4.56 goes up to 1961 - 300 higher than your factory RPMS, but still below 2000 RPMS.

On the highway, you can probably notice an increase of 300 rpms, but only if you try.

So, for your use case, I'd probably pick between 4.10 and 4.30.

If you drive "like there's an egg between your foot and the gas pedal" 4.10 is probably more economical of the two.

But if you drive more "normally" 4.30 probably gets to and holds higher gears sooner, and more than makes up for the incremental rev increase, and feels more "driveable" in general.
 
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Quick update:

Yesterday I stopped by my local drive line shop to inquire about re-gearing my Sahara on 35s.

They do recommend going to 4.56 gearing for my setup.

Shooting the sh*t, they tell me that the "new" D44 axles on JLs are not really D44s, even though that is what FCA calls them. This so-called "new generation" D44s on JLs are more like a hybrid between a D35 and a D44, or a "super D35" as one of the techs put it —i.e., a D35 with a number of D44 upgrades.

A few months back a customer comes in to regear his 2020 Sahara: the VIN shows that it has a rear D44. They order the parts, but as soon as they put the Jeep on the lift they can tell it isn’t a “real” D44. Sure enough, the parts don’t fit. In the end they make it work, but only after they spend two weeks figuring out exactly what parts are needed for the regearing.

They want me to bring my Jeep back on Monday to put it up on the lift. I will know more after they take a look.

Apparently this is also the reason there still are so few aftermarket LSD and locker options for JLs.

This is a bit of a bummer.
 

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Quick update:

Yesterday I stopped by my local drive line shop to inquire about re-gearing my Sahara on 35s.

They do recommend going to 4.56 gearing for my setup.

Shooting the sh*t, they tell me that the "new" D44 axles on JLs are not really D44s, even though that is what FCA calls them. This so-called "new generation" D44s on JLs are more like a hybrid between a D35 and a D44, or a "super D35" as one of the techs put it —i.e., a D35 with a number of D44 upgrades.

A few months back a customer comes in to regear his 2020 Sahara: the VIN shows that it has a rear D44. They order the parts, but as soon as they put the Jeep on the lift they can tell it isn’t a “real” D44. Sure enough, the parts don’t fit. In the end they make it work, but only after they spend two weeks figuring out exactly what parts are needed for the regearing.

They want me to bring my Jeep back on Monday to put it up on the lift. I will know more after they take a look.

Apparently this is also the reason there still are so few aftermarket LSD and locker options for JLs.

This is a bit of a bummer.
I would definitely not let that shop touch your Jeep. They have no idea what they are talking about.
 

jessedacri

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Quick update:

Yesterday I stopped by my local drive line shop to inquire about re-gearing my Sahara on 35s.

They do recommend going to 4.56 gearing for my setup.

Shooting the sh*t, they tell me that the "new" D44 axles on JLs are not really D44s, even though that is what FCA calls them. This so-called "new generation" D44s on JLs are more like a hybrid between a D35 and a D44, or a "super D35" as one of the techs put it —i.e., a D35 with a number of D44 upgrades.

A few months back a customer comes in to regear his 2020 Sahara: the VIN shows that it has a rear D44. They order the parts, but as soon as they put the Jeep on the lift they can tell it isn’t a “real” D44. Sure enough, the parts don’t fit. In the end they make it work, but only after they spend two weeks figuring out exactly what parts are needed for the regearing.

They want me to bring my Jeep back on Monday to put it up on the lift. I will know more after they take a look.

Apparently this is also the reason there still are so few aftermarket LSD and locker options for JLs.

This is a bit of a bummer.
The new D44s are certainly different than the JK ones but they're not D35 hybrids. I think the worst thing I've seen about them is that one of the roller bearings that the rear pinion uses is ball bearings to reduce contact and improve economy vs the typical large flat rollers to distribute load better as the previous gens do. And the front axle cast FAD housing sucks and shouldn't exist - I bent my axle there and had to go to an Ultimate D44.

I went 4.88s on 35s with the V6 and auto and it is nothing short of amazing both on and off road. 4.56s would be fine too but the 4.88s really let this drivetrain shine.
 

Stuckinthesand

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Quick update:

Yesterday I stopped by my local drive line shop to inquire about re-gearing my Sahara on 35s.

They do recommend going to 4.56 gearing for my setup.

Shooting the sh*t, they tell me that the "new" D44 axles on JLs are not really D44s, even though that is what FCA calls them. This so-called "new generation" D44s on JLs are more like a hybrid between a D35 and a D44, or a "super D35" as one of the techs put it —i.e., a D35 with a number of D44 upgrades.

A few months back a customer comes in to regear his 2020 Sahara: the VIN shows that it has a rear D44. They order the parts, but as soon as they put the Jeep on the lift they can tell it isn’t a “real” D44. Sure enough, the parts don’t fit. In the end they make it work, but only after they spend two weeks figuring out exactly what parts are needed for the regearing.

They want me to bring my Jeep back on Monday to put it up on the lift. I will know more after they take a look.

Apparently this is also the reason there still are so few aftermarket LSD and locker options for JLs.

This is a bit of a bummer.
Might want to look for a shop that truly understands differentials if they thought this was the same D44 as the previous models.

Currently, if you have purchased the new JL Wrangler, you have Dana 30 front and Dana 35 rear axles, unless you specifically bought one with upgraded Dana 44s. All Rubicon JL owners have a Dana 44 front and rear axle. However, these aren't your father's Dana 30, 35, 44 axles though as Dana has made these stronger and lighter than any other generation. So much so that these are not interchangeable with earlier generation axles.

https://media.spicerparts.com/cfs/f...JBaf/PERF-JLADVANTEK-42018.pdf?store=original
 
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aldo98229

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Might want to look for a shop that truly understands differentials if they thought this was the same D44 as the previous models.

Currently, if you have purchased the new JL Wrangler, you have Dana 30 front and Dana 35 rear axles, unless you specifically bought one with upgraded Dana 44s. All Rubicon JL owners have a Dana 44 front and rear axle. However, these aren't your father's Dana 30, 35, 44 axles though as Dana has made these stronger and lighter than any other generation. So much so that these are not interchangeable with earlier generation axles.

https://media.spicerparts.com/cfs/f...JBaf/PERF-JLADVANTEK-42018.pdf?store=original
No need to belittle the shop; it is very reputable. It just so happens that this is a small town, and they haven’t come across many JLs yet. The fact that they made it work for that 2020 Sahara speaks of their diligence.

The “issue” I have —if we can call it that— is that these “new and improved” axles don’t really exist outside of JLs. It would seem FCA asked Dana to develop these “hybrid” axles for JL (and JT), but they haven’t really caught on anywhere else. To the point that five years later, Eaton still refuses to develop a TrueTrac for them.
 
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The new D44s are certainly different than the JK ones but they're not D35 hybrids. I think the worst thing I've seen about them is that one of the roller bearings that the rear pinion uses is ball bearings to reduce contact and improve economy vs the typical large flat rollers to distribute load better as the previous gens do. And the front axle cast FAD housing sucks and shouldn't exist - I bent my axle there and had to go to an Ultimate D44.

I went 4.88s on 35s with the V6 and auto and it is nothing short of amazing both on and off road. 4.56s would be fine too but the 4.88s really let this drivetrain shine.
What kind of real-world MPG are you getting with the V6, 35s and 4.88s, if I may ask?
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