4.88, 5.13 or 5.38 debacle

Jeff 71

Jeff 71

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Joined
Feb 2, 2019
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Indiana
Hello Everyone
I have gone over the countless number of threads about gearing but there is always something that doesn't relate to what I want to do.
I have a 2006 LJ 4.0, 4 speed 42RLE Automatic that is 3.73 geared with a Dana 30 in the front and a HD Dana 44 in the rear with trac-lok.... ugh.... running on 33's

This is NOT a DD just a weekend trail rig where I am slow and steady through trails and some rock crawling - I have to drive it home so I have no plan of just "sending it" LOL

I am looking for a gear where in 4 wheel low and in 1st gear it allows me to meander up and over the trail and rocks, while staying off the skinny pedal

Maybe a throttle controller?

So my plan is to change the Dana 30 to a Dana 30 HP and add a Spartan Locker and go with 4.88 or 5.13 gears and run 35's.
In the far future run 37's.
Yes I know 37's are to much for the Dana 30 HP and will do another swap in the future.

What is the best gear for this type of trail rig?
4.88 or 5.13? 5.38?!?
Thick gears for the 30?
will a 5.38 even fit in a D 30?

I typically have 2 hours of travel on the highway/interstate to get to most of the trails.
Fuel economy isn't a issue as it is just a weekend rig
 
5.38s will not fit into the Dana 30. The deepest you can go is 5.13 and I believe only Revolution Gear & Axle provides that ratio. If you have plans for 35s, then gear for them now. Otherwise you are going to regear twice and waste money. With the 42rle, you will need 5.13s (ideally 5.38, but we already know they wont fit). A hand throttle is certainly useful, but with the auto, you should be able to meander over any obstacle without having to hammer down. 37s are also to large for the Dana 44. You dont need the HP 30 unless you are trying to get your driveshaft up and out of the rocks.
 
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5.13 all the way. Had 4.88s with your exact same setup and deeply regretted having not gone to 5.13.
 
5.13 is all you need to know. Think twice about the 37s.
 
5.13, judging by the shine on your Jeep, there is no reason to go over 33's, therefore, you do not need to look at 35's and the mess that comes with properly fitting them.
If you want a lower gear, like super crawl, you'll be dropping 4K on an atlas or looking for a Rubicon 241; the 231 in 4L and 5.13's does really well going slow.
I drive my 5.13/33's/42RLE a lot on the highway, my fuel mileage improved 1-3 mpg depending on how I drive it. I have no issue running 75 mph comfortably. It also does very well on the trail.
Stop over thinking it and go with 5.13 as 100's of other threads say to do. Save your money for other stuff.
 
Don't even CONSIDER 4.88, you would absolutely HATE that ratio with your 42RLE and 35" tires. 5.13 is the best ratio available to you. 5.38 would be better but your front Dana 30 won't accept anything more than 5.13.
 
Thanks for confirmation of 5.13’s guys.
I picked up the HP Dana 30 cause it was cheap and can always just sell it.
I am definitely gonna look at the hand throttle.
When on the trails and going up rocky incline my foot is constantly bouncing the skinny pedal.
 
Sooo
To continue the debacle I am looking at putting in the Spartan locker in the front HP Dana 30 and an air locker in the rear Dana 44 and am now second guessing myself.
My concern is there will be times it is driven on snow covered roads and I hear bad things can happen with lunchbox lockers.

My current plan:
Front- Change to 5.13's and install the Spartan
Rear- Change to 5.13 and install an air locker
 
I’m not changing the gearing decision.
5.13 all the way.
I just need to be swayed a little on the lockers.
I think I’m gonna go with the spartan on the front and air in the rear.
I can’t afford 2 air lockers
 
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I agree with a rear selectable. Just not sure about the auto front in the snow. I don't have experience with one on snowy city streets.
 
What about rock climbing
Is the rear more important or the front?
Trying to get up on a rock edge will the rear push up?
Currently that’s my biggest issue with out a locker
 
There are some out there that suggest if your going to go with just one selectable locker to put it in the front axel. What say the TJ guru's? I've been thinking of locking the front and staying with the LSD in the rear.
 
MutantNinjaTJ said:
There are some out there that suggest if your going to go with just one selectable locker to put it in the front axel. What say the TJ guru's? I've been thinking of locking the front and staying with the LSD in the rear.
Click to expand...


I spent about two seasons with a locked front and LSD rear. It got a lot done, but there is no comparison to having both ends locked again.

The rear gets the most weight and traction during a climb and would benefit the most from a locker. Though considerations like the Dana 35 and inexpensive lunch box lockers are reasons why so many lock the front first.

If I were to redo the lockers on my Rubicon, I would strongly consider an auto front and a selectable rear. But snow in the city would be an argument to keep the selectable front.
 
The 5.13's have arrived :)

BUT,
They didn't send reverse cut for the HP 30 so I have 2 options
1- Forget the Dana 30 swap - LP to HP - and just go with what they sent and install on the LP 30 with the Spartan or
2- Get the correct gears and do the HP swap?

Is there really a huge gain from doing the swap?
 
Jeff 71 said:
The 5.13's have arrived :)

BUT,
They didn't send reverse cut for the HP 30 so I have 2 options
1- Forget the Dana 30 swap - LP to HP - and just go with what they sent and install on the LP 30 with the Spartan or
2- Get the correct gears and do the HP swap?

Is there really a huge gain from doing the swap?
Click to expand...

Whether it's a "huge gain" is subjective. If however you want 30% more strength at the gear set and higher clearance at the driveshaft, then it's worth it. Since you plan to run 35" tires and already have the HP Dana 30, the real question is why wouldn't you wait for the correct gears and do it right the first time? You'll regret it if you don't!
 
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