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Old 04-22-2008, 10:43 PM
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Default CV rear drive shaft for a 60

Guys,

I have located a front double cardan drive shaft for an FJ 60 and was wondering if i could take it and make it a rear drive shaft. would it be worth it to rebuild it (lenghten it) to make it a rear one or should i start from scratch?

Are the front shafts just as beefy as the rears?

I have a vibration I am chasing in the back and a stock shaft balanced well is not curing it..

and yes, my pinion angle is not "good" it is off by a few degrees.
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Old 04-23-2008, 07:10 AM
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It is very much worth it. Toy CVs are brutally strong. The Chili runs CVs front and rear.

You will still need to make sure your pinion angle is good. Rule of thumb, with leaf sprung rear axles, go 2* down from straight with a CV. This allows for some axle wrap under throttle.

If you measure 8* down after putting in the shaft (and no, you cannot accurately estimate what it will be without actually having the shaft in place), don't figure that you therefore need 6* shims. It doesn't quite work that way, as the axle moves in an arc with the shim in place the match doesn't come out quite even. You therefore may need to 'fiddle' and go through a couple shim options. The rear pinion on the Chili is a tad high (moving the drivetrain forward and changing crossmember location can do that), and some day I need to address that. But currently it causes few issues, maybe some slight vibes on the highway but I've gotten used to it.

When using shims, avoid the aluminum/potmetal shims like the PLAGUE!! They WILL NOT last, and will strand you with a broken centerpin. Use only steel. Shims in the front are bad juju - the exception perhaps being weld-on shims. ANY lift from shims is a bad thing in the front though - axle hop. Torsion bars come to mind as a solution. Some day I will put a torsion bar in the rear of the Chili; hop ain't bad at all, but the difference should be noticeable.

Roger Brown is a great source of shims and will allow you to swap shims with him until it is right. There is a good page on driveline angles and issues on his site.

http://www.4crawler.com/4x4/ForSale/Shims.shtml

Oh, yeah, and my experiences above are SOA. SUA works similarly but in reverse. Kinda. YMMV.
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Old 04-23-2008, 08:16 AM
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"So, if you have the driving shaft turning at say 1000 RPM, the driven shaft will vary from 710 up to 1410 RPM as it rotates, averaging to 1000 RPM. This is what causes a driveshaft to vibrate." (talking about angles being off)

Wow. and all along I thought it was due to an imbalance. This guy is good. First time anybody has been able to explain it to me.

Marco needs to get to work on making these angles all the same. No wonder it really vibrates when it's really putting the power down... this makes a ton more sense. Wow.

I wonder if my output flange is square side to side... when i put the motor in in moved it to the left to make things fit.. I bet that threw everything off... oh jeeze.
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Old 04-23-2008, 08:34 AM
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The only truck CV That isn't strong is 1983 and under front on the mini trucks. (small pattern) They don't SUCK, but they are "less than desireable"

I run double cardan joints front and rear. I have some vibration on the back, and a bit more on the frontThe front is a balance issue from the agricultural spline slip joint.)

The rear vibration is imperfect rear u-joint angles. It vibrates just a little more under load, so I tink it is a little too high. I have chosen to leave it.
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Old 04-23-2008, 08:44 AM
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i run an 85 4runner front shaft for the rear in my 40 and it's great. 36" swampers and a v8 and i'll run 85-90 mph with no vibration.
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Old 04-23-2008, 04:15 PM
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The only problem with 60 series front CV shafts is that Toyota ujoints are not available for the CV. This means that you end up with Spicer which I have broken many times in my 62.
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Old 04-23-2008, 04:51 PM
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oh yikes, thats no good... man that kinda makes me rethink the plan.. maybe thats why the guy is selling it.
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Old 04-24-2008, 07:51 AM
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Yech... interesting detail about cruiser parts. Go minitruck. Should be able to pick one up fairly cheap from Yoda Jim.
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Old 04-24-2008, 09:48 AM
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Quote:
Originally Posted by rover67 View Post
oh yikes, thats no good... man that kinda makes me rethink the plan.. maybe thats why the guy is selling it.
If you don't have too much lift, why not just shim the axle so your pinion and t-case angles are aligned?

At a certain amount of lift, the u-joint operating angles are high enough that you are going to shorten their life and increase the chance of a catastrophic failure, but if that's not the issue, I'd just correct the angles for starters.
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Old 04-24-2008, 12:25 PM
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Nay, I am headed that way... after having looked at this more and more i have learned a lot. I think i need to stick with the regular driveshaft in the rear since the pinion and t case angles are close. The front though, is a different story. I have some crazy vibrations up there as speeds increase and I think it is due to the fact that the front pinion points straight at the t-case.... which i don't want to change since i have my caster where i want it. so... I think that instead of using the CV style shaft in the rear like I was thinking, I need to just get my pinion angle right in the back, and actually use the cv shaft in the front. Kinda the opposite of what I wanted to do in the first place.
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