Some Guidance Please

When building any Jeep there are 5 basic divisions.
1-Standard
2-Optional
3-Trans Vintage
4- Trans Model
5- Trans Make ( manufacturer )

If no STANDARD MODEL and VINTAGE of Jeep meets your need then consider the factory OPTIONAL components for those models.
The above provides for staying true to factory Jeep production.

If that does it suit your need, then consider the 3 types of modified jeeps.
The Trans-Vintage classification provides for some changes such as a 1955 CJ5 having reverse shackles combined with the post 1965 Dauntless engine.
It’s composed of CJ-5 components but the years are mixed up.
A Trans-Model Jeep build allows for even more deviation so long s it’s sll assembled from genuine Jeep components.
An example might be a CJ2A tub and having wide track Dana 30 front axle.
And finally ones imagination is the limit for any of the Trans-Make builds.
These builds are not pure Jeep and there is no mandated standardization.
Myself I do not even pretend to remotely approach this level of mechanical genius.
The mating of Unimog portal axles with Quadra Trac are far beyond my level of expertise.

Model selection is paramount to every Jeep build because that determines what assemblies will fit.
After model selection the engine selection yeilds the greatest impact on appropriate drivetrain selections.
After all you want to your build to end up as a complete and synchronous system.
So determine what you really expect from the build and proceed accordingly.

 

thats good to know arent the large hole cases super rare?

 

No. All D20 cases are large "hole". The only caveat is you want to find one with the side fill plug rather than the rear plug.

 

Good to know. I am so impressed with all the responses and info and insight. This is hands down the best group

 

For a more detailed discussion of this, look at this thread-
Dana 18 To Dana 20 Conversion Advice

 

Axle setups really aren’t that bad. I’d rather do gears than custom floor work.

Axle gear changes might not scope creep as much as brakes/steering in an Early.

And yes, low end tq is great.

 

I'm at 57:1 I believe. Just to review I think the T18 is 6.32, Dana 18 is 2.46, and my rears are 3.73. Its slow slow with 33's and plenty of on-road grunt. I had side pipes with mufflers (not cherry bombs) and it was louder but not bad. Now that the Jeep is under the knife for power steering its getting a real muffler and we're quieting her down all the way.

 

I have a 231, SM 465, 4:88's, overdrive and 33" tires. I can easily cruise the freeway at 65 mph at around 2600 rpm. My overall crawl ratio is 78:1. I wouldn't change a thing.

 

i just had a d30 with 4.11 and arb locker and off set rear d44 and compressor for the arb drop in my lap for a price i couldnt pass up. so i think ill run with that numbers looked good with sm420 and even std d18

 

Here's another calculator that includes the ratios for most transmissions and t-cases used off road. It also has a compare function so you can look at different setups side by side.

http://www.grimmjeeper.com/gears.html

Mike

 

That's a good one!

 

thats what i use really like it

 

Wow that is a good one. Looks like I have a 68.53 crawl ratio and at 750 rpm I would be doing 1.07 mph, at 3,000 rpm I would be doing 4.3 mph

 

found this awhile back
Drivetrain Final Crawl Ratio Calculator (Engine Rotations Per Tire Rotation)

 

My rig came stock with a V6 and 3.73 gears. When the T14 gave up, I switched to a T18A and 4.10's. With 31" tires, the gearing is a tad too low for street use and the first gear ratio became ridiculous. If I had to do it again, I would opt for the T18 and kept the gears stock.

OD's are a nice touch, but unless you trying to overcome excessively low gearing, isn't worth the trouble since you already have 3.73's in there now.