What do you guys think about the rear axles from FJ40's? I don't know much about LC's so I'm kind of in the dark. I'm contemplating using one in the back of my flatfender (350 > SM420 > Spicer18). The width and the offset are what I like about this axle. What are the week points of this axle? How does it compare to a Dana 44? If I don't use this axle then I will likely use a Dana 44.
Here are some specs that I found. I don't really have anything to compare thses numbers to.
The size of the Cruiser axle shaft is comparable to a Dana 60. They do neck down to 30 splines for the side gears at the carrier. 77-older axles are 4.11 with coarse 10 spline pinions, and are weaker. 78 saw 4.11 gears with fine spline pinions. 79+ are 3.73 gears with fine spline pinions. ALL Aftermarket gear sets are fine spline pinion. If you control pinion/axle wrap, they are a very strong axle. Their only disadvantage is the c-clip design. Ring gear is considered 8.875, not the commonly mis-noted 9"+ size. (It's all where you measure) The housings are all steel and easy to weld to, and are quite strong. Disk brake conversions are readily available. Ring-ratios available include 3.73, 4.11, 4.56, 4.88 and if you don't mine trimming a ring gear tooth, 5.29.
DING DING DING!! hahaha I never broke an axle, however, I broke 3 pinions in the rear (2 fine spline, and one coarse spline) and one coarse spline in the front.
HAHA you've got that right. I think I pulled something loading those up the other day.
All the bad stuff people have said is true, but I still like them. With an anti-wrap bar of some kind, I think they are pretty good. I like a heavy axle to keep the CG lower. I have yet to break one, hell, I haven't even broken a birf since I was 16. I must be driving like a sissy. :flipoff2:
OK this is good. I wanted to know the bad stuff along with the good stuff.
Couples questions for the LC fanatics. What is the axle shaft spline count and what is the diameter of the shaft at the neck-down?
I'm confused as to why the pinion is so weak. I found the pinion specs on Dana 44's which are below. The LC rear end seems superior. What am I missing?
nooo, we have a dude at work with a 78 LC and he has only broke an axle shaft where it necks down, but he also has a warn full floater kit for it and disk brakes. the axles in it are 1.5" but still neck down to the stock size in the diff. he has a 330hp 350 in it right now and only breaks newfields in the front. BTW we have pictures of him smoking all 4 tires on one rock ledge.
I never had a problem with my rear end on my fj which I had for 13 yrs and beat the hell out of it and on just about every trail around this area, nothing ever went bad with it, and the guy I sold it to still beats it so it is a solid set up.
Most of the shaft is 1 7/16", it necks down to ~1 7/32" near where it goes into the third member. This neck down area is where most of them break, but I must say that broken axles are not common in my experience.
I don't know why the pinion is so prone to breaking. Axle wrap has a really bad effect on the rear LC axle. SOA arrangements with longer, softer springs contribute to this. I have never broken a pinion and I have been known to romp on it, my friend with 36" TSLs, SOA, and a V8 never broke one and he REALLY romped on it and he never broke one either, we both have coarse splined pinions too, which are weaker. On the other hand, another friend just broke a coarse pinion on Fordyce and he is SOA with the I6. My brother broke one on PAVEMENT in a STOCK SUA Cruiser once! But he can break anything so I wouldn't expect those results.
Basically, it's a good axle and with an anti-wrap bar, I would choose it over a 44. That's just me. Most people would want the best if they go through all of the trouble of a swap. The LC rear is not the BEST, but it suits my needs and many peoples' needs just fine.
It should also be noted that the pinion shaft necks down to 1 5/32" near the splines. This is where I see most of them break. The whole pinion shaft is not 1.575".
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