Newbie Questions

Hi All,
I had bought my '01 TJ 4.0L Auto a few months back and as part of figuring out what it has and what I need to add to my wish list, I am confused about
the axle ratios on my TJ. All the material I have read on the internet and even Jeep website (www.jeep.co.nz) says that Dana 44 on a 4.0L Auto comes with 3.73 axle gearing, but my build order printed by the dealer said mine came with Dana 44 4.0L Auto and 3.07 axle gearing. I didn't believe it, so I raised one front tyre and rotated it four times and counted 6.25 rotations on the front propeller shaft, which basically confirms that I do have 3.07. I also finally found the manufacturers tag on the pumpkin saying something something Spicer and then a bunch of number that had 3.07 stamped in the beginning. So my questions are:
1) How difficult and expensive would it be to go to a higher ratio? (addition to my wish list)
2) Whats the biggest tyre size I can go with 3.07 (assuming re-gearing is expensive). Currently I have 225/70 R16 BFG AT KO on 16 inch five spoke Jeep Icon Alloy wheels. I do want to get bigger tyres once the current one are all worn out because currently the Jeep is sitting too low (I have been scrapping my fuel tank skid plate on some trails).
3) I also wanted to take the diff / tranny / ac wents a little higher than where they are. It rains often and heavily in Auckland and getting water in weird places is not uncommon. I have found the ac went, which just unceremoniously ends in the firewall. I have also found the went on the front axle, which actually has a rubber hose that ends at the top at the same level at the upper most point on the radiator (great). But I could not find any wents on the rear axle or the transmission. Any guidance would be appreciated as to the locations and sizes so that I could buy rubber hoses to extend them to reasonable height.
Thanks you all for taking the time to read and answer my queries. This has been a great group and I have learnt a lot about Jeeps just by reading posts for the past few months.
Kind regards TW
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about
and
so
Are you sure it's a D44, I also thought they only came with 3.73's.

About $1,000US for parts and should be done by an experienced mechanic with the proper tools. Labor (and any parts markup) would be extra.

one
been
You could probably go as far as 31's but you will loose power. Much more and you will need re-geared and some kind of lift. Those BFG's won't ware out till about 40K miles.

Both my axles have vent tubes (D30 & D44) but none on the tranny.

has
No worries, mate!
--
JimG
80' CJ-7, 258 CID
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figuring
comes
mine
do
3.07
with
is
than
water
Your tcase has a vent tube too.

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You would think I would remember that since I was the one that put the 4 to 1 kit in it!
Thanks for the memory jog :-) JimG
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Yes, I have confirmed it by sight and matching to shapes on the internet. Also, build order from the dealer listed it as Dana 44. Additionally, the mechanic at the dealers said that TJ Renegades in NZ only come with Dana 44 (he wasn't sure about the gearing options though).

with
Great, another addition to my wish list. I thought those things were expensive (USD 1.00 = about NZD 1.80).

ware
I will just have to drive around a lot to get them worn out! I have got about 35k kilometers on them now, which is just about half way.

Looks like I will have to go under the TJ again, but this time with a torch and some coffee.

Thanks.
TW
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torch
When you say torch, some will think you are going to burn a new vent hole yourself (with an acetylene torch), or keep your coffee hot. Having traveled "down under" a bit, I recon you're talking about a flashlight.
JimG
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Man we live in an interesting world. Yes, I meant flashlight but unfortunately it has been raining for the past 24 hours and I don't have a covered garage. I'll just have to wait.
TW
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hole
Wait for what? Just fire up that torch and go check the gas tank. You'll be warm enough soon ... :-)
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be
Don't put ideas in my mind.... Its not raining so far this morning, so I might be going under it soon.
TW
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Sadly its probably true - I have the 3.07s for now.
Dave Milne, Scotland

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about
and
so
First, you want a lower ratio, which is a higher numeric value.

one
been
You will be stuck at 30" tires for the most part. You need to change some suspensiion stuff to get bigger than 30s under there anyway. Actually, you can fit 31s but the gears will not work out very well.

The diff vents should be pretty close to the level of the intake system. If the intake sucks up some water, the diffs getting wet will be the least of your problems.
The trans has a vent that closes if it goes under water, the tcase has a vent hose that is attached to the firewall, and the rear diff has a vent hose that goes up inside the fender.

has
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Now see, I wondered about that and left it alone...
Mathematically speaking, wouldn't a higher "ratio" be correct, which correspond to a "lower" gear? For example: If you use a higher (50:1 vs. 25:1) gas to oil ratio in your chain saw, you are adding more gas to the oil.
Naturally we all know that the higher the number (ratio), the lower the gear and visa versa. Maybe we should only use "higher" and "lower" when referring to gears.
Just pickin' :-)
JimG
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gear
Your fuel analogy is flawed. 25:1 is a richer mixture than 50:1, but 50:1 gears are easier to turn than 25:1. (not that this would be a very useful gear ratio for an automobile).
In the fuel ratio, you are using 25 parts of gas for each part of oil, or 50 parts of gas for each part of oil. If you have a 25:1 fuel ratio, then you have twice as much gas as compared to the 50:1 ratio that you suggested.
But, an engine with a differential of 25:1 must work harder than one with a 50:1 ratio. You will not get as much work done with the 50:1 ratio, but the work that is done will be with less strain on the engine, assuming we are not talking about running around at redline.
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50
Bzzzzt ... wrong answer. 50:1 is a richer mixture. Think of what burns in the combustion chamber ... fuel and air. The oil is for lubrication and cooling and doesn't burn. 50 parts fuel to 1 part oil results in more fuel being delivered when compared to 25:1. You will have to lean out your jetting to accommodate running at 50:1.
--
- Jeff
- ........................ then again, what do I know.
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A 50:1 mixture is 50 parts of gas for each part of oil. A 25:1 mixture is 25 parts of gas for each part of oil. Given the same amount of oil, there is twice as much gas in the 50:1 mixture. Or, given the same amount of gas, there is less oil in the 50:1 mixture.
The discussion is about gear ratios, and the gas mixture was thrown in to illustrate gearing questions. I only pointed out that the fuel mixture analogy is flawed when used to illustrate gearing issues.
Gears are a lower when the numbers used to express them are numerically higher, gas is "thinner" when the oil/fuel mixture numbers go up.
wrote

50:1
useful
or
you
in
fuel
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And I only pointed out your misstatement. Regardless of the earlier discussion, 50:1 is richer than 25:1.
--
- Jeff
- ........................ then again, what do I know.
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Is that the way you richen your two cycle? God Bless America, ill O|||||||O mailto: snipped-for-privacy@aol.com http://www.billhughes.com /
-jc wrote:

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Yes. Forget about the oil when considering the richness of mixture and concentrate on the fuel/air ratio. Oil is for lubrication and cooling of the internals. More oil = less fuel + same air = leaner. Less oil = more fuel + same air = richer.
--
- Jeff
- ........................ then again, what do I know.
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So rather than jetting it, you just remove the lubrication. God Bless America, ill O|||||||O mailto: snipped-for-privacy@aol.com http://www.billhughes.com /
-jc wrote:

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of
No. Remove lubrication to the point that the motor is still adequately lubed but not spooging out the exhaust and then jet appropriately. In practice it's a bit of back and forth until you find the perfect balance. Using different oil will change the lube/spooge/jet equation. Some lubricate better, some burn more, so on.
--
- Jeff
- ........................ then again, what do I know.
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