6th Gear?

[Chugiakguy]

Knock yourself out with this gear calculator: http://www.grimmjeeper.com/gears.html

Step 1: Aisin D478
Step 2: NP241/NV241/NVG241
Step 3: None
Step 4: run the numbers on whatever gear ratio you want: 3.45 ... 4.10 ... 4.56 ... etc...
Step 5: Stock Tires ( 255/75R17 )

I spent a long time with this calculator before I decided on 4.10's

Thanks again, 230yj! I really appreciate all the info.

Sponsored

 

[Blazing Saddles]

Hi all,

I am new to the forum. I have the 4.88 rear axle and I am just below 2500 rpm at 65 mph.

That is expected. With the 4.88 gearing on the stock 33s (I believe this option is Rubi only) you are not expecting normal RPMs at high speed. My wife's sport is around 2k at highway speeds 70-80mph). However, she has the auto, which is amazing. It is also important to note if you have the 4.88s on a manual or an auto, as both options are available now. With the low gearing and the 100:1 crawl on the 33s, you aren't really looking to top end, but for power at the low end. Where I live, you are much more likely to be cruising at 45 mph than 60+. This change matters significantly with the way you will drive. If you add in towing, I would suspect gearing is a valid concern.

 

[Chugiakguy]

Knock yourself out with this gear calculator: http://www.grimmjeeper.com/gears.html

Step 1: Aisin D478
Step 2: NP241/NV241/NVG241
Step 3: None
Step 4: run the numbers on whatever gear ratio you want: 3.45 ... 4.10 ... 4.56 ... etc...
Step 5: Stock Tires ( 255/75R17 )

I spent a long time with this calculator before I decided on 4.10's

That gear calculator can be totally engrossing! I've already been playing with it, but I'm going to have to look at it more closely later on. Thanks!

 

[18Celtics]

Hello, and welcome to the forum 18Celtics!
I am fairly new here myself.

Can we assume that you have a Rubicon, with 33' tires? Just trying to make a frame of reference for your observations with your 4.88 gearing.

Thank you Chugiakguy.
Yes, i have the Rubicon with 33s.

 

[18Celtics]

That is expected. With the 4.88 gearing on the stock 33s (I believe this option is Rubi only) you are not expecting normal RPMs at high speed. My wife's sport is around 2k at highway speeds 70-80mph). However, she has the auto, which is amazing. It is also important to note if you have the 4.88s on a manual or an auto, as both options are available now. With the low gearing and the 100:1 crawl on the 33s, you aren't really looking to top end, but for power at the low end. Where I live, you are much more likely to be cruising at 45 mph than 60+. This change matters significantly with the way you will drive. If you add in towing, I would suspect gearing is a valid concern.

Definitely not looking to go faster than 120 km/h.
I plan to go for a 3.5 inch lift with 35s, which I why I opted for the 4.88.

 

[Chugiakguy]

02/2022 Prices:
Dana/Spicer 4.10 Gear Sets Front/rear: $349 x 2 = $698.00
Eaton M186 Front ELocker: $1049.00
Yukon Gear Install Kits: $279 x 2 = 558.00
Gear Installation (each axle): $499.00 = $998.00
Tazer JL Mini Programmer: $299.00
+ TAX
Total Parts/Install out the door: $3,785

Hey Toothirtytj, I noticed that in your breakdown of the costs of your regearing, you included a Tazer Mini.

Forgive me if this is an ignorant newbie question, but for what exactly did you need the Tazer Mini? I can understand having to use it to reset the shift points with an automatic transmission, but since you have a manual, what needed to be reset with it after your regearing?

 

[toothirtyj]

Hey Toothirtytj, I noticed that in your breakdown of the costs of your regearing, you included a Tazer Mini.

Forgive me if this is an ignorant newbie question, but for what exactly did you need the Tazer Mini? I can understand having to use it to reset the shift points with an automatic transmission, but since you have a manual, what needed to be reset with it after your regearing?

The Tazer is used to tell the vehicle what the new gearing is. Without doing so will cause the speedometer/odometer to be off which can also play havoc with the transfer case thinking it's operating too quickly in 4 low throwing malfunction codes and setting off idiot lights on the dash.

I also use the Tazer to keep the Stop/Start disabled without having to press the dash button every time I start the Jeep.

 

[Chugiakguy]

The Tazer is used to tell the vehicle what the new gearing is. Without doing so will cause the speedometer/odometer to be off which can also play havoc with the transfer case thinking it's operating too quickly in 4 low throwing malfunction codes and setting off idiot lights on the dash.

I also use the Tazer to keep the Stop/Start disabled without having to press the dash button every time I start the Jeep.

OK, thanks! And that makes perfect sense.

I've long known about the need to reset the speedometer & odometer (or the computer that controls them) after going to larger tires, but of course with a different diff gearing, all that would be off as well. Sorry for the stupid question!

 

[toothirtyj]

OK, thanks! And that makes perfect sense.

I've long known about the need to reset the speedometer & odometer (or the computer that controls them) after going to larger tires, but of course with a different diff gearing, all that would be off as well. Sorry for the stupid question!

Have you made a final decision on your gearing choice?

 

[Chugiakguy]

Have you made a final decision on your gearing choice?

Not definitely, but I am strongly leaning towards the 4.56.

One factor aside from that choice, though, is finding out if there is any local shop here in Southcentral Alaska who can even do the regearing, or who would be willing to.

I'd be willing to consider tackling it with some help, but a regearing is well beyond my automotive experience, and I wouldn't consider it on my own without some help from somebody with significantly more mechanical experience.

 

[MJ48]

So I'm not the only one!

I'd be very curious to know how your regearing goes for you, BBack, especially as we have virtually the same Jeep (mine is a 2022 2-door Willys Sport).

There are speedt/ gearing/rpm /tire size charts available on the internet to guide you in your gearing selection.

 

[MJ48]

I am always intrigued by what other manual drivers see. I am in 6th gear by 50-55 mph and stay in it constantly. I can only imagine that people that have an issue with 6th gear are either using sport gearing or trying to move a lot of weight. I have 4.88s on 33s. I also live in an area that goes up over 3k in elevation in about 10 miles or so.

It's the 4:88's that make the difference

 

[Blazing Saddles]

It's the 4:88's that make the difference

Absolutely. These threads go all over the place because of differences in gearing and tires.

 

[Red Willy]

Well, I just ordered gears and set up install with our local shop. Since i am going to stick with 33s and 90% of my seat time is on road, I went with 4.10. After mulling over charts of rpm vs speed, and considering my light usage off road, I think it's going to be my best overall choice.

 

[Cutterone]

I really want to go 4.56 in my 2021 Sahara 6sp. It's not on the highway much. Whoever thought the combination of the 3.45 gears and the spacing of ratios in the 6sp was a good idea should be demoted!!! The 6sp should have come with 4.10 in all, option to 4.56 or 4.88 in rubi...

Sponsored