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Discussion Starter · #1 ·
So I am about ready to do a gear swap. I have a 2.5l stock 30-35danas. Looking at doing an 8.8 swap and changing gears in both the 30 and 8.8. Is 4:88 low enough? Shoud I go with a 5:?? Anyone have a similar set up? It's not a DD. thanks.
 

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4:88s are the tallest gear you can put in the stock differentials.
 

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What do you want the jeep to do?

Any hwy?

Only trail?

Yes, the D30 and D35 can only handle up to 4.88, and you obviously want the front and rear to match no matter what axle you install.

You didnt mention what tires you are going to run, is that what you mean with "35" in the title? That will also make a difference to what gearing depending on what you want the jeep to do.
 

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With a 4.88 gear, and 35" tire, assuming an AX5 trans behind the 2.5, you will be doing 2388 rpms, in 5th gear, at 60. That to me suggests its not low enough unless you will spend more time on the highway than on the trail. A 5.50 or more would get you into the power band of the motor.
 

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Discussion Starter · #5 ·
camarozz said:
What do you want the jeep to do?

Any hwy?

Only trail?

Yes, the D30 and D35 can only handle up to 4.88, and you obviously want the front and rear to match no matter what axle you install.

You didnt mention what tires you are going to run, is that what you mean with "35" in the title? That will also make a difference to what gearing depending on what you want the jeep to do.
Yes it already has 35 inch tires on the stock 4:10 gears. I do not drive it in the HWY. it is not a daily driver. I do drive it on trails and some around town occasionally. I guess if nothing lower than a 488 will fit in the D30 then that is my answer. I thought some ran 5:38 but they must have different axles if they won't fit.
 

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Yeah, thats probably it.

4.88's will help, but again if you want it to be more useful for your lifestyle I would consider much lower. It just depends on what you are willing to live with. There is no requirement to use 5th gear either. 4th gear with 4.88 will get you to 2800 ish RPM at 60 which is very usable.

Now if you were to use smaller tires, that would also help. Like 33's would make 5th usable, and according to the calculator I have it suggests the tallest I would use with 4.88's.
 

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Discussion Starter · #7 ·
camarozz said:
Yeah, thats probably it.

4.88's will help, but again if you want it to be more useful for your lifestyle I would consider much lower. It just depends on what you are willing to live with. There is no requirement to use 5th gear either. 4th gear with 4.88 will get you to 2800 ish RPM at 60 which is very usable.

Now if you were to use smaller tires, that would also help. Like 33's would make 5th usable, and according to the calculator I have it suggests the tallest I would use with 4.88's.
I was thinking lower than a 4:88 too. However I can't seem to find a lower gear to go in the Dana 30. Are you aware of where I could get a lower gear? Some posters on this thread have said that 4:88 is the lowest. Also I already have the 35s on the jeep. So changing tire size isn't an option.
 

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You cannot get a gear ratio lower than 4.88 in the d30 or d35. You have to change to another set to get a choice like that.
 

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Discussion Starter · #9 ·
camarozz said:
You cannot get a gear ratio lower than 4.88 in the d30 or d35. You have to change to another set to get a choice like that.
Thanks that what I thought. You had mentioned in your previous post if i wanted it to be more usable you would go lower than 4:88. I didn't know that you meant swapping axles.
 

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There is a page on "Novak Adapters" that gives you an easy to fill out formula.You put in what you are running and it will show MPH & RPM. You can put in different tire size, gearing ect.. and it computes it for you.You will have to look around their page it might be under transfer cases, I,m not sure.Dont know if this applys to your question, but there you go.
 
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