Gear/ Carrier Set up

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Buds Garage
Posts: 2
Joined: July 9th, 2021, 1:38 pm
Vehicle Year: 1980
Vehicle Make: Jeep
Vehicle Model: CJ7

Gear/ Carrier Set up

Post by Buds Garage »

Hello all,

I have seen many suggestions on gear set up and I am at a cross roads to make a decision. First here is the build I'm working on.
Frame off restoration 1980 CJ7 - I bought this not running so I have never driven it before to know its characteristics.
1980 CJ7 Renegade
3.08 gears
Building 4.6L Stroker with T176 4sp trans, Dana 300 transfer
Dana 30 front(narrow) AMC20 rear (narrow)
2-2.5" lift
31' tires (would like to stay 31's but if the lift is too much and I need to fill in the wheel wells a bit I would be open to go 32's or 33's)
Any opinion on tire size to lift?

This is fun weekend Jeep that will mostly cruise around town, camping, beach driving ( some highway driving to get to destinations) and would like it set up so my wife and kids will enjoy driving it as well.
All charts point to run 3.73 - 4.11 gearing however the break point of having to switch the front carrier is 3.54.
1) With the added power and torque with the stroker would 3.54 ratio be sufficient with 31's?
2)What is I need to go up to 32 or 33's -
3) if I need to switch carriers is it a straight swap that I can just get a 3.73 and up case and switch internals?
4) is there a different carrier or locker that I should look into based on my application

Thanks for your input, Unfortunately I was not able to drive it prior to know the characteristics so I would like to hear personal experiences.

Thanks,

Kevin
TJryder
Making Progress
Making Progress
Posts: 75
Joined: July 29th, 2018, 1:03 pm
Stroker Displacement: 4.6
Vehicle Year: 2000
Vehicle Make: Jeep
Vehicle Model: TJ

Re: Gear/ Carrier Set up

Post by TJryder »

Hi,

I just did a regear on a stock renix 4.0 and AW4 sloshbox with 3.55 stock. I went to 4.88 on 31's despite the fact that max recomended is 4.56.

If you have a manual - I guess it would be an AX15 unit?

1.st gear on auto box is created by torque converter.

If you compare manual AX15 with 3.08 gearing and 2-nd and up are almost identical to 1-2-3-4 with final gearing of 3.55

With super low gearing that I did on 31-s - the toy is now drivable. Before it was a dog. At 60mph I get arround 2.300rpm from an engine. Going any faster - would be pushing it.

The down side of super low gearing - the driveshaft spins much faster and you get in the resonance pretty soon. I did correct the angles - but SYE with low gearing I guess is a must.

Would I do it again? Yes

Stock setup:
On the TJ I have - 1-st gear on a NV 3550 is 4.01 (3.83 for AX15) with final gearing of 3.07 and transfer case gearing of 2.72 you get 33:1 in crawl mode
On XJ I have AW4 - 1-st gear is 2.8, diff ratio is 3.54, transfer case is 2.72, final crawl ratio is 27:1. With torque converter efect - you are prety much on the same level.

So if manual - I would toss those 300$ more for new carriers and go 4.11 and be done with it.

Just my 0.02$
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Buds Garage
Posts: 2
Joined: July 9th, 2021, 1:38 pm
Vehicle Year: 1980
Vehicle Make: Jeep
Vehicle Model: CJ7

Re: Gear/ Carrier Set up

Post by Buds Garage »

Thanks TJryder,

I have a t176 4speed manual. If I had a 5speed 4.11, 4.56 would be a no brainer. Just trying to find a good compromise with the 4speed for light off road and highway driving.
TJryder
Making Progress
Making Progress
Posts: 75
Joined: July 29th, 2018, 1:03 pm
Stroker Displacement: 4.6
Vehicle Year: 2000
Vehicle Make: Jeep
Vehicle Model: TJ

Re: Gear/ Carrier Set up

Post by TJryder »

T167: 1-st: 3.56, hi gear 1
AX15: 1-st: 3.83, hi gear 0.79

So it is 7% taller in low gear and 20% lower in high gear

So it is close to stock TJ without using fourth gear.

It will do 20% more rpm in top gear. Try driving one at thar RPM to see if it is OK for you.

IMH it should feel the same or even less rpm with 4.11 at 60 as my XJ with 4.88 gearing (0.75 × 4.88 = 3.66)

Yet - 4.11 will give yo 20% more Tq on wheels at takeoff.

IMHO
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TJryder
Making Progress
Making Progress
Posts: 75
Joined: July 29th, 2018, 1:03 pm
Stroker Displacement: 4.6
Vehicle Year: 2000
Vehicle Make: Jeep
Vehicle Model: TJ

Re: Gear/ Carrier Set up

Post by TJryder »

Oh, forgot to mention, try to use this calc to work over through your scenarios:


https://www.4lo.com/calc/gearratio.php
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