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post #1 of (permalink) Old 10-13-2000, 05:04 PM
RedSandDog
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RockCrawling Gearing question

I am gathering the last few parts together for my driveline, but I want to make sure I am not setting myself up for axle problems so please give your opinion of this set up.

I am putting in an NP435 (I am sure everyone is tired of hearing about that) that I want to couple to a Dana 300 with the 4 to 1 Tera kit, and keep my 3.73 axles. I would get decent highway gearing in 2HI but get 98.77 to 1 crawl ratio. I have stock Dana 30/44 with a Trak-Lok in back and will lock the front too.
My concern: are those axles and (I assume) stock gears up to the task of a 100 to 1 crawl ratio? Is that too much torque? I have the funds to do the axles or the Tera kit but not both. What do people think?


'74 CJ-5, 258, NP435, D44 w/LockRite
(OK, well the np435 is in the garage next to the Jeep)
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post #2 of (permalink) Old 10-13-2000, 05:14 PM
**DONOTDELETE**
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Re: RockCrawling Gearing question

IMO the 30 is gonna be your weak link, but if you don't go over 33" tires you will be OK. You might want to upgrade the 30 to Warn axles, but I think you said you are low on funds. One thing, a stock Track-Lock is also pretty wimpy, you would do very good to replace it. It is not a good rock crawling diff, I tried for a while with one, too easy to fool, went with a Detroit.

Brad
ORC Land Use Section Editor
http://www.off-road.com/land
Vice-Pres. Rock Garden 4 Wheelers, Farmington, NM
post #3 of (permalink) Old 10-13-2000, 05:21 PM
**DONOTDELETE**
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Re: RockCrawling Gearing question

Wish I could be more help. I'm trying almost the same set-up except for the tranny. I'm looking for a NV4500 right now. I used a lot of info from BBSs and some math/engineering caculations. I think I'm going to end up with a couple of axles from a 76/77 Bronco tucked underneath. I'm real interested on the opinions and experiences of the old hats of this BBS as well. Sounds to me like a very strong set up so far. What kind of power plant were you going to torque all this with? Twisting an axle gets real easy with that type of reduction. Remember, the more splines on the axle the better. If you have to have a weak link, the axle is easier to work on and cheeper than the gearing.

Tread lightly and stop to smell the roses - Traveler
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post #4 of (permalink) Old 10-13-2000, 05:23 PM
RedSandDog
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Re: RockCrawling Gearing question

Yah, that Trak Lok came with the Jeep when I got it, and I don't think much of it. I would prefer Detroits front and back. I am looking at 32" tires, so the 30 should be OK (hope).

'74 CJ-5, 258, NP435, D44 w/LockRite
(OK, well the np435 is in the garage next to the Jeep)
post #5 of (permalink) Old 10-13-2000, 05:28 PM
RedSandDog
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Re: RockCrawling Gearing question

I am going to keep the 258, go with Howell EFI, an RV cam and maybe deck the block to bring the compression up a little. Not a real high HP thing but should be drivable on the rocks. My real concern is that if I have most of the torque multiplication happening before the axles that they be up to handling it from the driveshaft.

No likey when things breaky.

'74 CJ-5, 258, NP435, D44 w/LockRite
(OK, well the np435 is in the garage next to the Jeep)
post #6 of (permalink) Old 10-13-2000, 05:30 PM
RedSandDog
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My bad, LockRite, not Trak Lock

Sorry my bad, that was my old Jeep. It has a LockRite, and I am not real crazy about it.

'74 CJ-5, 258, NP435, D44 w/LockRite
(OK, well the np435 is in the garage next to the Jeep)
post #7 of (permalink) Old 10-13-2000, 05:54 PM
**DONOTDELETE**
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Re: My bad, LockRite, not Trak Lock

Well, you might want to pick up a used outer shaft and a couple used inner shafts along with a u-joint or 2.

Brad
ORC Land Use Section Editor
http://www.off-road.com/land
Vice-Pres. Rock Garden 4 Wheelers, Farmington, NM
post #8 of (permalink) Old 10-13-2000, 06:33 PM
 
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Re: My bad, LockRite, not Trak Lock

I also think your axle u-joints would be the weak link. I have a mildly build 258, with 4.27 gears/ARB's/33 and I like to think I am very conservative on the skinny pedal, but I managed to break an axle u-joint a few weekends ago.
Luckily, I had a spare axle shaft, but next time it breaks in with the Warns!
Bob in MA

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post #9 of (permalink) Old 10-13-2000, 07:06 PM
 
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Re: My bad, LockRite, not Trak Lock

The 3.73 gears being not that low are going to put a lot more strain from the diffs back to the engine. I would think that you may want to carry some extra 1310 drive shaft, and out put shaft yokes, U joints, straps/U bolts, and possibly even slip shafts.Or go to the 1330 or 1350 yokes and Joints. Dont forget its not just how easy the motor can turn the wheels, but where the stress loading occurs, with lower gears not as much stress is placed on the drive shafts.

Jeff
89 Wrangler
I take my Jeep "On the Rocks",usually "With a Splash of Addrenalin"
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