gears vs transfer case

JLUin818

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forgive me in advance if this is a dumb noob question....

i have a Sport on 35s with auto transmission. some times when offroading there is a difficult obstacle to climb up. its like the jeep doesnt have enough power to get up and over it so i have to give it more gas.

is this more of a result of the Sport's transfer case or its gearing? ie, which one should i upgrade to tackle this occasional issue? obviously both would be ideal but if i could only do one, which one should it be?





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ThirtyOne

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With the manual I would definitely say transfer case. With the auto, I'm not sure.
 

whiteglad

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If 4 low (2.72:1 in the sport) isn't enough gearing, you need to do one of these:
1. rubicon 4:1 transfer case
2. stiffer differential gearing (must do front and rear the same)
3. shorter tires
 

beaups

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forgive me in advance if this is a dumb noob question....

i have a Sport on 35s with auto transmission. some times when offroading there is a difficult obstacle to climb up. its like the jeep doesnt have enough power to get up and over it so i have to give it more gas.

is this more of a result of the Sport's transfer case or its gearing? ie, which one should i upgrade to tackle this occasional issue? obviously both would be ideal but if i could only do one, which one should it be?
If “giving it more gas” gets you up and over, you have enough power and there’s nothing more to do.
 

DOOKEY

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the stock 3.45

Alright. So here's the math.

The 850RE has a 4.71 first gear and 3.13 second gear. Here are your current crawl ratios.

4.71x2.72x3.45 = 44.20:1 respectively.
3.13x2.72x3.45 = 29.37:1 respectively.


Changing the math around can show you what is capable if you change the tcase gears.

4.71x4.0x3.45 = 65:1.
3.13x4.0x3.45 = 43.19:1.

If you leave the case alone and change out the gears in your axles.

4.71x2.72x4.56 = 58.42:1.
3.13x2.72x4.56 = 38.82:1.

So we'll focus on this one alone.
New case gears. 4.71x4.0x3.45 = 65:1.
New axle gears. 4.71x2.72x4.56 = 58.42:1.


There ain't that much difference. So I'd go with what you plan to use more. Plan to drive more on the road? I'd do the axles. Plan to go off road more? Do the case. Unless you plan to go to bigger tires in the future. I'd try to gear my axles only once. If you plan to go up in tire size the case may be the bigger benefit.
 

Yondu_JLU

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Alright. So here's the math.

The 850RE has a 4.71 first gear and 3.13 second gear. Here are your current crawl ratios.

4.71x2.72x3.45 = 44.20:1 respectively.
3.13x2.72x3.45 = 29.37:1 respectively.


Changing the math around can show you what is capable if you change the tcase gears.

4.71x4.0x3.45 = 65:1.
3.13x4.0x3.45 = 43.19:1.

If you leave the case alone and change out the gears in your axles.

4.71x2.72x4.56 = 58.42:1.
3.13x2.72x4.56 = 38.82:1.

So we'll focus on this one alone.
New case gears. 4.71x4.0x3.45 = 65:1.
New axle gears. 4.71x2.72x4.56 = 58.42:1.


There ain't that much difference. So I'd go with what you plan to use more. Plan to drive more on the road? I'd do the axles. Plan to go off road more? Do the case. Unless you plan to go to bigger tires in the future. I'd try to gear my axles only once. If you plan to go up in tire size the case may be the bigger benefit.
I swear this guy always has the best responses. 👍😂
 

zeebo56

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Alright. So here's the math.

The 850RE has a 4.71 first gear and 3.13 second gear. Here are your current crawl ratios.

4.71x2.72x3.45 = 44.20:1 respectively.
3.13x2.72x3.45 = 29.37:1 respectively.


Changing the math around can show you what is capable if you change the tcase gears.

4.71x4.0x3.45 = 65:1.
3.13x4.0x3.45 = 43.19:1.

If you leave the case alone and change out the gears in your axles.

4.71x2.72x4.56 = 58.42:1.
3.13x2.72x4.56 = 38.82:1.

So we'll focus on this one alone.
New case gears. 4.71x4.0x3.45 = 65:1.
New axle gears. 4.71x2.72x4.56 = 58.42:1.


There ain't that much difference. So I'd go with what you plan to use more. Plan to drive more on the road? I'd do the axles. Plan to go off road more? Do the case. Unless you plan to go to bigger tires in the future. I'd try to gear my axles only once. If you plan to go up in tire size the case may be the bigger benefit.
From what you stated here it seems it is not a huge difference between doing one or the other (gears vs case) when offroading is desired but with gears you also get the benefit of daily driving. So changing gears out also helps with offroad ability and should be noticeable.

@JLUin818 and I were having a discussion and curious which would yield more benefit offroading, T case vs differential gear upgrade and how much difference there would be. You provided great info, thank you.
 
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JLUin818

JLUin818

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Alright. So here's the math.

The 850RE has a 4.71 first gear and 3.13 second gear. Here are your current crawl ratios.

4.71x2.72x3.45 = 44.20:1 respectively.
3.13x2.72x3.45 = 29.37:1 respectively.


Changing the math around can show you what is capable if you change the tcase gears.

4.71x4.0x3.45 = 65:1.
3.13x4.0x3.45 = 43.19:1.

If you leave the case alone and change out the gears in your axles.

4.71x2.72x4.56 = 58.42:1.
3.13x2.72x4.56 = 38.82:1.

So we'll focus on this one alone.
New case gears. 4.71x4.0x3.45 = 65:1.
New axle gears. 4.71x2.72x4.56 = 58.42:1.


There ain't that much difference. So I'd go with what you plan to use more. Plan to drive more on the road? I'd do the axles. Plan to go off road more? Do the case. Unless you plan to go to bigger tires in the future. I'd try to gear my axles only once. If you plan to go up in tire size the case may be the bigger benefit.
most of that doesnt make any sense to me but the last paragraph does lol. thank you for the information and im sure it will benefit many Sport owners.
 

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