Dana 30 is a keeper?

MikeO

MikeO

TJ Enthusiast
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First Post Here…

So, I have a 98 TJ presently running 3.73 on 30in tires. It has a 2.5 in. suspension lift and I will be putting on 285/75/16 tires, 32.8 diameter, 57 lbs + 21 lb. wheel. I think the 3.73 gear ratio is not optimal?
Question One: What would be the optimal gear ratio. (I am never going to 35s)

More… Rather than pour money into re-gearing a Dana 35, I am itching for a Dana 44. However, I have read here that the front Dana 30 is quite sturdy at a lower gear ratio.
Question two: So, am I right that it would be better to re-gear the Dana 30 to match, rather than put on a Dana 44 in the front… at least in the short term?

Thanks…
 
What transmission is in your TJ? Is it an auto or a manual? That will help determine the ideal gear ratio. But no, 3.73 gears will not be optimal regardless, those are some of the worst gears you can get for larger tires.

Your Dana 30 is fine with 33" tires. Throw some Revolution chromoly axle shafts in it and a locker, and you'll have a nice and stout axle that will handle everything you throw at it.

Don't be so quick to dismiss the Dana 35. I wouldn't waste the money upgrading to a Dana 44 only to tun 33" tires. I would build yourself a Super 35. Check out this thread: Should I upgrade my Dana 35 axle?

The Dana 35 can be a very strong axle that handles up to 35" tires very well. Don't believe all the internet talk you hear about the Dana 35 not being up to the job. It certainly is, as long as you build it right and don't drive like a moron.

So, to answer your questions:

1) We need to know if you have an automatic or a manual in order to tell you what gear ratio you'll need.
2) Yes, it would be better to re-gear the Dana 30. Putting a Dana 44 in the front would be a huge waste of money, and not even worth it unless you were spending big bucks on some sort of custom high pinion Dana 44 front axle (i.e. a Currie RockJock or similar). The Dana 30 is more than capable and then some.
 
The 30 will be good with 33's and up to moderate wheeling. Install some 5-760x axle u joints while in there. The 44 is a great swap if you can find one at a reasonable price. Do not dismiss the Super 35 kit from Revolution. It adds 30 spline alloy axles and a choice of lockers, ARB or Detroit. If you don't want or need a locker, some alloy 27 spline axles and a Truetrac will work with 33's and up to moderate wheeling.
Ratios: 4.10 if you have the auto, 4.56 if 5 spd.
 
I second the Spicer 5-760x u-joints as well!

Rob is right on the gearing too, I should have just said that instead of asking which transmission you had.

Also, don't get me wrong, a Dana 44 is a great axle, but don't bother doing that swap unless you get one for a damn good deal. It's not worth paying $800 for one, when you can use the money and just make a Super 35 out of your existing Dana 35 axle.

If Blaine and those guys are doing Johnson Valley (pretty much as extreme as it gets) with a Dana 35 rear and a Dana 30 front, then you'll be more than fine.

Just remember, you can break ANY axle if you're stupid enough, no matter how strong it is.

As long as you're not one of those guys who is way too happy with the accelerator, you'll be more than fine.
 
I have the 4.0L 6 engine and the 32 rh 3 speed transmission. Wonderful advise on not having to go to a Dana 44. Hard to find and the G2s are expensive. Amazing responses. Thanks
 
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Also, I hear you about the 4.10, but I've read here that the difference from a 3.73 and a 4.10 is negligible. Is it a bad idea to just go to a 4.56 with the 3 speed auto??
 
MikeO said:
Also, I hear you about the 4.10, but I've read here that the difference from a 3.73 and a 4.10 is negligible. Is it a bad idea to just go to a 4.56 with the 3 speed auto??
Click to expand...

I personally think you'd be fine with the 4.56 in the auto. In fact, that's probably the route I would go personally.

I have the 42RLE automatic in my Rubicon and I went with 4.88 gears. I also have 32.8" tires as well.

So yeah, I think the 4.56 might be slightly better for you. See of it is preference of course.
 
MikeO said:
Also, I hear you about the 4.10, but I've read here that the difference from a 3.73 and a 4.10 is negligible. Is it a bad idea to just go to a 4.56 with the 3 speed auto??
Click to expand...


There is really no need to regear from 3.73 to 4.10 while running 33s with the 32rh. I've been running that combo for five years, and I think if you do a little searching on the net not many people will advise you to spend the money on such a negligible jump.

I absolutely would not regear to 4.56 on 33s with the 32rh. If you were planning on 35s, yes, but your original post said that is not in your plans.
 
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4.56 is pretty deep on a 1:1 final drive, like 3300 at 70. If you don't mind running 60-65 on the fwy, yea, 4.56 would be awesome.

3.73 to 4.10 isn't a huge change and may not be very noticeable with the jump to 33's. Ideally with the 3 spd and 33's, something like 4.30 would be great but unfortunately not available for your diffs.
 
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I wouldn't worry about it. I have driven plenty of miles on 33's with 3.73 gears, 4.0l and the ax15 5 speed. It's not bad. You downshift, but 70 is fine on the highway.
 
You will get lots of opinions with gears.

My goal with gears is to run with performance rpm specs of my Jeep at OEM. For you that means 33's with 4.30, but that ratio isn't available, so I'd go with the next best thing, 4.56. 4.11 wouldn't even be worth it.

Can you live with something less than optimal? Maybe. That's why I'd get the tires first, then drive it awhile and decide. If you can't live with it, regear. I've found that there are different strokes for different folks. For example, some live in hilly country, others live in flat places. That could make a big difference as to whether you can live with being undergeared. My .02c
 
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32RH, 33s with no intention of ever going to 35s, 4:10s are optimal! It's exactly what I'm running. I jumped from 3.07s to 4:10s so I can't speak to 3.73s but I would imagine it can't be that bad. Mine is a daily with a few Offroad trips a year. 4.10s woke mine right up and got me back in the power band.

*I read and asked around for over 2 years before I forked up the cash. I believe it was a guy named Jerry who has answered this question several times on other forums. He has owned and worked on a lot of Jeeps and knows his stuff. And he was dead on with his advice. Only thing I would advise, if you're doing a lot of highway driving be prepared to be running in the 3000 rpm range at 70-75ish range (don't remember exactly). This scares some in concept, but is actually optimal for the i6 4.0. (Again, ask those who have the set up.) Many who haven't experienced it first hand will disagree.

3.73 = lower RPMs at 70mph, 4.56 = higher RPMs at 70mph

Another thing that can make a major adjustment in throttle response and shift timing is adjusting your kickdown/throttle cable. If you don't know what I'm talking about look it up or reach out and I can help you out.

But overall, for the health of your vehicle, 4.10s are where you want to be. Browse the forums, Check the charts, and hear from people who have actually done the swaps themselves. And for reference, those with manuals or 4 speed autos are entirely different.

**for the price, I would stick with 3.73s. If you ever wanted to go to 35s, then skip 4.10s and go to 4.56. But if you have the expendable cash, and you aren't going over 33s, you want 4.10s. I'm getting 14.5-15 mpg which is much better than the 10-11 mpg I was averaging before the upgrade.

But as I said, make some adjustments to the kick down cable, drive it around, and tweak it based on the shift points you desire. 15-30 mins of tweaking might surprise you!

Not my video, I know it says Cherokee, but for the 97-02 TJ it is the same cable. Newer TJs changed it to a plunger system.


*I would recommend holding the cable in place before and while the beige clip is removed. Adjust it to your preference, then set the clip back in place and let go of the cable. I say this because my cable has minor load or tension that will reset the cable and counteract my adjustments.


Sent from my iPhone using Tapatalk
 
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Ranger_b0b said:
I wouldn't worry about it. I have driven plenty of miles on 33's with 3.73 gears, 4.0l and the ax15 5 speed. It's not bad. You downshift, but 70 is fine on the highway.
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The Ax15 has much lower gears than the 32RH. To compare, you would basically have to start out in 2nd, then 3rd, then 4th and stop shifting. The 5 spd 1st gear is 3.83 vs 2.74, a huge difference. (Not my numbers, from Grimm Jeeper)
 
Rob5589 said:
The Ax15 has much lower gears than the 32RH. To compare, you would basically have to start out in 2nd, then 3rd, then 4th and stop shifting. The 5 spd 1st gear is 3.83 vs 2.74, a huge difference. (Not my numbers, from Grimm Jeeper)
Click to expand...

I missed where OP said he had the three speed auto. Thanks for clearing that up. I would still try it before I dropped another 1200 on gears
 
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