These stock axles strong enough??

[sakodye]

Ok, so I have a '63 Willys CJ5 with the model 25 front and Dana 44 rear axles, a small lift and 33" tires, a chevy 283 and the T90 and T18. The axles have 5.38 gears and lockers, which I assume are the powertrax lock-rite lockers. Are those lockers ok or are they junk? Also, I know the axles suck, but think if I'm easy on the skinny pedal I'd make it through the rubicon? If I do try the rubicon, what parts are likely to break? - so I'll have an idea of what to carry with me.

Also, wtf is a lunchbox locker??

[WA-HCRC]

search, btw, suprized the 25 hasnt died yet.

[1972CJ5+1]

I saw a couple of 30/20 and 30/44 combos on the rubicon and they had no issues. I'm sure it had more to do with driving style than anything else. Use the turnouts and bypasses and stay off of the skinny pedal and you should be fine. I assume you mean d18, not a t18 (two transmissions) even so, with 5.38s you have a pretty decent crawl ratio. I would expect to see front axle ujoint area to be the first to go followed by front ring and pinion followed by driveshaft ujoint or a lockout hub. The lower ring and pinion helps the driveshaft, but hurts the axle shafts and hubs. The rear 44 isn't the strongest, but should work fine if treated nicely. Time for a front axle upgrade. A pair of 44s or a 44/60 might be nice. Not too $$$, but significantly stronger than now.

[budget76]

get rid of the heep and buy a scout :flipoff2:

[sakodye]

Thanks 72cj5 - that's the type of opinions I was looking for. I'd heard the weakest part of the 25 front was the spider gears, but since it's got a powertrax locker it doesn't have the spiders (correct me if I'm wrong) so I was just wondering what might be next to go.

And yes I meant d18, and I figured out what a lunchbox locker is, and no I don't want a scout!

[66CJdean]

Since you have the T90 I expect that you won't have much problem becase you will be wheeling at such a high speed IE: not a good crawl ratio. But once you change that 3spd out for a 4psd you will probably start breaking things. It is up to how hard you push it.

[sakodye]

Ok dean, you say once I change out the 3 sp for a 4 sp, so that must be a common swap? To what 4 sp? What's the advantage? Does it have a much lower first?

[66CJdean]

4spd is refering to a 4spd tranny. 4 gears where your T90 is 3spd... 3 gears. Most truck 4spd we all put in Jeeps are twice as low in 1st gear as your T90 so low range is reall low and slow but that = more engine torque to the wheels so breaking an axle is much more common.
Example
T90 has a 3 to 1 first gear X your low range in the Spicer 18(2.43) X 5.38 in the diff's = 39.22 That means for every 39.22 revolutions of the motor = 1 rev of the tires
Now take a common 4spd like a SM465 it has a first gear of 6.65 so take 6.65X2.43X5.38= 86.94 rev's of the motor = 1 rev of the tires.
So the down side to all this gear reduction is it doubles the amount of torque the engine can apply to the tires or to break axles in this case.

[sakodye]

Ok ok, I knew that you meant a 4 spd tranny - I'm not that new!! I've just always had an auto in my K5 and never worried about a manual til I got this jeep. So, I was just unfamiliar with how much lower the first gear is on a 4 speed than on my 3 speed. Sounds like it'd be nice to have. Is it an easy swap? How much different is the case length?

I don't care about breaking the axles much, as long as I don't end up stranded somewhere. I'll run them til I break them, then just have an excuse to go bigger.

[1972CJ5+1]

Just to add to 66CJdean's info: There are some 4 spds with less reduction if there is a specific ratio you are looking to obtain. A t-18 for example is often desired for the 6.32:1 1'st gear ratio, but can be had in a 4:1 ratio also. One nice thing about the granny first in the sm465,420 and the t-18 (6.32:1) is that the 2nd-4th ratios are pretty close to your current 1st-3rd. This allows you to still drive in a similar manner as before, and just use first when you need it. The t-18 4:1 is a typical close ratio truck 4spd without the large ratio change from 1st to 2nd. Just another option. Breaking an axle might leave you stranded. If it is a front, you can likely unlock the hubs and put it in 2wd. Assuming you can get out of where you got stuck in 2wd. If it's a rear, you have issues with a semifloat. Depends on where it breaks and how. I agree with 66CJdean: "It is up to how hard you push it."

[d.d.machine]

I had a 68 cj5 with a Fhead T90, D18 , D27 and D44... I beat the chit out of it for about 5 years and the only parts that went out a lot was the 27 front ... I switched in a 25 and never busted axles agion... I think what saved mine was the motor could not put out chit for power. Damm I miss that hunk of junk.