Which transfer case to buy for lower crawl ratio?
- Thread starter Emmitt Forbush
- Start date
You may want the Ford 435 and install the dodge 23 spline output shaft and tail shaft housing, the ford is the correct input and the dodge is the correct output.
I have an Atlas in my YJ, they are not loud at all, the drive shaft and twin stick shifter is the hardest thing to accommodate.
Not really. You'd have to go from 3.73 to an approx 5.55 axle ratio to equal the offroad benefit of changing the 2.71 tcase 4Lo ratio to 4.0.
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Why? Not being a dick, but why is the DS difficult to accommodate?
I’d been eyeing a 2-Speed atlas for a while but if that’s the case, I’m not dropping another $800 on driveshafts when I just replaced mine.
On any TC swap unless you replacing with the same exact model Drive shaft work is required in most of the case if not in all.
I've been around several of the Tera units. They are typical Tera. They have a design flaw but if you kept them under the over rev limit, they were a viable solution to this exact problem. I installed several, and they did exactly what they were supposed to do as long as you didn't over rev them.
They aren't difficult to measure and install, they just aren't cheap. If you haven't set up the twin sticks or the cable shifters, you are in for some joy.
EzPeezy
TJ Enthusiast
You're of course correct for offroad ability. I was thinking more for all-around enjoyment and usefulness.
Yes but this thread was about a better crawl ratio. The tcase has the most effect on that.
xxdabroxx
TJ Addict
Not sure what it would take to fit but a NV4500 has a pretty darn low 1st gear.
NV4500 Specs
1st 3.83:1;
2nd 2.33:1;
3rd 1.44:1;
4th 1.00:1;
5th 0.79:1, and
Reverse 4.76:1.
NV3550 is
1st 4.01:1;
2nd 2.32:1;
3rd 1.40:1;
4th 1.00:1;
5th 0.78:1, and
Reverse 3.57:1.
Crawl ratios with 4.56 and np231 (2.72) for reference:
4500: 69.5:1
3550: 49.73:1
AX15: 47.5:1
Crawl ratios with 4.56 and 4.0 transfer case
4500: 102.33
3550: 73.14
AX15: 69.85
NV4500 Specs
- Forward Speeds: 5
- Dates Produced: 1992 - 2005
- Case Length: 12.375
- Stock Adapter Length: 6.25 Dodge & 8.125 GM
- Bellhousing Length: 6.50 GM
- Case Material: Cast Iron
- 1st Gear Ratio: 5.61 or (6.34 GM 92-94)
- 2nd Gear Ratio: 3.04 or (3.44 GM 92-94)
- 3rd Gear Ratio: 1.67 or (1.71 GM92-94)
- 4th Gear Ratio: 1.00
- 5th Gear Ratio: 0.73
- Reverse Gear Ratio: 5.04 or (6.24 GM 92-94)
- Transmission Weight: 195Lbs
- Max Engine Torque: 460
- Gross Vehicle Weight Rated: 15,000
1st 3.83:1;
2nd 2.33:1;
3rd 1.44:1;
4th 1.00:1;
5th 0.79:1, and
Reverse 4.76:1.
NV3550 is
1st 4.01:1;
2nd 2.32:1;
3rd 1.40:1;
4th 1.00:1;
5th 0.78:1, and
Reverse 3.57:1.
Crawl ratios with 4.56 and np231 (2.72) for reference:
4500: 69.5:1
3550: 49.73:1
AX15: 47.5:1
Crawl ratios with 4.56 and 4.0 transfer case
4500: 102.33
3550: 73.14
AX15: 69.85
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If you guys really, really want the lowest possible crawl ratio then it's time to think automatic transmission. The torque converter in an automatic gives what is in effect an infinitely low 1st gear ratio.
xxdabroxx
TJ Addict
Where is the fun in that Jerry... LOL
I think the sm420 and sm465 are more common swaps for that low 1st gear.
This is what Novak has to say about the NV4500:
"The NV4500 has an initially attractive overdrive gear, but with a low gear of only 6.34:1 (early units) and a gear span of 7.71 and 5.61:1 (later and most common units) and a gear span of 6.96, its position against the heavy-duty four speeds (SM465, T18, SM420 or NP435) is not a lot better. Choosing the right axle ratio and tire size in conjunction with the right transmission is a smarter strategy than using overdrive as a patch to the system. "
Too bad Jeep didn't read this little footnote when they built the 42RLE.
"Choosing the right axle ratio and tire size in conjunction with the right transmission is a smarter strategy than using overdrive as a patch to the system."
"Choosing the right axle ratio and tire size in conjunction with the right transmission is a smarter strategy than using overdrive as a patch to the system."
xxdabroxx
TJ Addict
Overdrive helps you to be able to run a lower rear axle ratio though and still be highway friendly. That rear end ratio has a lot to do with your crawl ratio too.
Looks like the 4500 with AA's kit is almost 2" longer than a stock transmission though which would be problematic.
Looks like the 4500 with AA's kit is almost 2" longer than a stock transmission though which would be problematic.
MallCrawlOnTons
TJ Enthusiast
Cmon. A web wheeler like you doesn’t know about the current aftermarket 300 case out there.
Edit: https://behemothdrivetrain.com/products/dana-300-colossus-case?variant=18205764386934
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MallCrawlOnTons
TJ Enthusiast
To the op. I would do a doubler before I started swapping transmissions. Especially when thinking about an old school granny geared 4 speed or a one ton granny gear 5 speed.
Rubicon case, doubler, or aftermarket 300 case with jb’s gears then atlas. That’s the order I would look at getting a lower crawl ratio personally.
Rubicon case, doubler, or aftermarket 300 case with jb’s gears then atlas. That’s the order I would look at getting a lower crawl ratio personally.
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