Going to 4.88 or 5.13 for 37s?

[dcm80401]

You are missing the point--it is a non-issue because it will not be happening as often on those 10 speed transmissions because the engines in front of them develop enough torque that the transmission does not have to drop to a lower gear to compensate for the loss of torque.

It is the same for 392 and 3.0TD engines. You do not see them complaining about losing 8th gear after installing larger tires and not re-gearing. Why? Because the engines make enough torque to deal with the loss of gearing and thus the transmission does not have to drop into a lower gear (e.g. lose 8th gear).

If the 3.6L was the 3.0 TT that is in the Wagoneers OR was making 350HP and 400 LB-FT, this would also be a non-issue, but the 3.6L does not produce enough torque at lower RPMs which it would be running with larger tires and not re-gearing to compensate.

3.6L = 285 HP and 260 LB-FT
2.0T = 270 HP and 295 LB-FT
3.0TD = 260 HP and 442 LB-FT
3.0TT = 420HP and 468 LB-FT
392 = 470 HP and 470 LB-FT
Ford 2.7TT = 330 HP and 410 LB-FT

Do you now see why it is an issue with the 3.6L? If the 2.0T was not turbocharged, it would be more of a problem with it too--but the turbo helps to compensate.

I am going agree with you.

4xe 375 HP and 470 lb -ft
My 4xe Rubicon wieghs in at 6100# I can hit 8th gear (not very often)on I-70 in Denver and have no problem going up to the Eisenhower. Offroad no problems at all. Stock 4.10.

I considered going 4.88 once (if ever) software update comes out. I don't think I need it.

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[CarbonSteel]

Im running KO2’s with 5.13’s with the 2.0 and at 75mph Im at 2200 rpms. I am getting 19.2 mpg right now with winter blend and winds the past week or so in the low teens.

What size K02's? I would expect your RPMs to be higher with 37" or smaller tires.

 

[TylerV76]

What size K02's? I would expect your RPMs to be higher with 37" or smaller tires.

37’s D rated. Ko2’s run pretty small though. Just under 36 mounted.

 

[JeepinJason33]

I’ve been reading that gearing will definitely void my warranty, at least for the axles. Would having 37s alone void my warranty if I ended up having problems with my stock axles within the warranty timeframe?

When my lockers stopped working (known issue fixed by Tazor), they immediately offered to replace the axles. Was ridiculous as it is just oil in the sensor, but apparently the sensors were on backorder and the axles were not. Anyway, they knew I had the gear change and were still going to replace the axles. The problem was that they would not regear it or take out the gears from the axles that were in place. So, I would have needed to again pay the labor to get all of that done. Fortunately, the Tazor patch/plug bypass worked.

 

[CarbonSteel]

37’s D rated. Ko2’s run pretty small though. Just under 36 mounted.

Interesting; with 37" K02 Load Range C, I am at exactly 2500 at 75 with 5.13 (3.6L though).

 

[TylerV76]

Interesting; with 37" K02 Load Range C, I am at exactly 2500 at 75 with 5.13 (3.6L though).

Im sure you have but you changed tire size with a tazer or jscan right?

 

[CarbonSteel]

Im sure you have but you changed tire size with a tazer or jscan right?

Yes, of course (both gear ratio and measured tire size).

 

[Rodeoflyer]

I’ve been reading that gearing will definitely void my warranty, at least for the axles. Would having 37s alone void my warranty if I ended up having problems with my stock axles within the warranty timeframe?

Think about what you would need to warranty on the axles. it's .0001% issue, mainly if you overfill and blow out the seals. OR you if beat on your jeep really hard beyond what you think is humanly possible and twist an axle spline? You're still within $1k repair bill with you at fault.

And there are other options to remove the sensors etc. I typically wait 15k miles. If you don't have an engine/driveline failure in 15k miles, it will (likely) go 100k (maybe 200k) with proper maintenance.

 

[TylerV76]

Yes, of course (both gear ratio and measured tire size).

Yeah I forgot to do the tires at first and was hitting about 24-2500 rpms at what I thought was 75. Turns out it was about 78-79 lol.

 

[CarbonSteel]

Yeah I forgot to do the tires at first and was hitting about 24-2500 rpms at what I thought was 75. Turns out it was about 78-79 lol.

I have checked my speed multiple times against other vehicles and radar units and it is accurate.

I will assume the difference is due to 2.0T versus 3.6L (though that really should not matter assuming both are 8 speeds).

 

[kapk22]

When my lockers stopped working (known issue fixed by Tazor), they immediately offered to replace the axles. Was ridiculous as it is just oil in the sensor, but apparently the sensors were on backorder and the axles were not. Anyway, they knew I had the gear change and were still going to replace the axles. The problem was that they would not regear it or take out the gears from the axles that were in place. So, I would have needed to again pay the labor to get all of that done. Fortunately, the Tazor patch/plug bypass worked.

What are you referring to when you say “tazor patch/plug bypass”?

I have the Tazer Mini and set the tire size accordingly. I did see I could change the gear ratio in the settings. Is this what you are referring to?


I was considering adding a throttle controller for $70. Not planning on a full programmer. I don’t like the turbo lag, but the power is pretty good, still with the 37s and the 2.0.

 

[At Risk Ute]

Went with 4.88s for my JLR with the 2.0T and 37” KM3s.

Still in the 500 mile highway break in period so haven’t wheeled yet. However, big Improvement around town and running up the mountains.

Tranny getting less of a workout. Should have regeared earlier.

 

[kapk22]

Went with 4.88s for my JLR with the 2.0T and 37” KM3s.

Still in the 500 mile highway break in period so haven’t wheeled yet. However, big Improvement around town and running up the mountains.

Tranny getting less of a workout. Should have regeared earlier.

Nice flex!

I am leaning toward 4.88s now, after reading someone getting into 8th gear at 45mph all the time and rpms running too high on the highway. My tires are a bit larger than yours though, and more aggressive (37x13.50r20 Nitto Mud Grapplers) I wonder if that much of a difference in size would make a noticeable difference in gear changes and rpms. I cannot afford gears at the moment anyway. I appreciate the feedback, as always.

 

[At Risk Ute]

Nice flex!

I am leaning toward 4.88s now, after reading someone getting into 8th gear at 45mph all the time and rpms running too high on the highway. My tires are a bit larger than yours though, and more aggressive (37x13.50r20 Nitto Mud Grapplers) I wonder if that much of a difference in size would make a noticeable difference in gear changes and rpms. I cannot afford gears at the moment anyway. I appreciate the feedback, as always.

I’d take @CarbonSteel ‘s advice. 4.88 for the turbo and 5.13 for the na motor.

 

[Gorilla57]

I’d take @CarbonSteel ‘s advice. 4.88 for the turbo and 5.13 for the na motor.

Exactly. Only reason I’m still 4.88 is due to my Livernois tune. The 3.6 now makes just enough HP to push my heavy rig on 37’s up the mountains.

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