| Subject: |
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Re: Re: Re: 8 3/4 or dana? |
| Name: |
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JimmieD |
| Date Posted: |
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Mar 6, 06 - 7:13 AM |
| Dodge-Link |
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http://www.firmfeel.com/default.htm |
| Message: |
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The 8 3/4" is a very strong axle, but still no comparison to a Dana60 9 5/8".
The 8 3/4 usually requires some work to set it up right: largest pinion is the late '489 carrier setup, at 1 7/8". Next is the '742 carrier which has a 1 3/4" pinion. You don't want a '741 as they are too puny for any real power. The problem with the '489 is that the pinion depth is set with a 'crush sleeve, as a collar that crushes according to applied torque on the pinion nut. It's much easier, but under high horsepower the sleeve can be 'self-crushing' and blow the whole R & P to smithereens! Ask me how I know.... The fix is to upgrade to the aftermarket solid spacer in place of crush sleeve which makes a VERY stout rear, but you then have to set pinion depth with shims which requires a gauging set or lots of trial and error. Gauges are over $100, but trial and error with red lead gear marking compound works fine if you're patient.
Two different limited slips were available, Spicer clutch type [used in casting # '657, '741, '742] or Auburn cone type use in casting # '489. Either one works very well, but the Auburn is not rebuildable for the average guy without a machining operation which some claim causes a weaker unit and other problems. You can buy a brand new Auburn limited slip from any of several vendors. The new clutch packs are readily available for the early units for about $100, the new Auburn is around $300.
You can use the preferred 1 7/8" pinion from a 489 case, in a '489 case, with the early clutch type limited slip, with a solid crush sleeve and have a very stout rearend. To calculate shop rates to set one up estimate the value of your truck and multiply by 3 or 4, on a good day. You can do it yourself. Also the 1 3/4" pinion 742 is suitable as is for most truck applications of medium duty to at least 400 h.p.
2 different axles available on 8 3/4", but DON'T use the tapered: use later flanged semi-floating. Both types of axles require that the axles be pulled to lube outer bearings.
Dana 60 has a MUCH stronger axle housing, much stronger carrier, better bearings, larger diameter pinion, full floating axles, self-lubricating outer bearings and is much stronger in every way than an 8 3/4. Most are 8 lug, but Ford used a lot of 5 lug.
I opted for the 8 lug D60, and swap to an 8 lug 3,500 lbs front axle, even though I had all the brandy new parts to set up the '489 8 3/4" just right. For my needs much cheaper and easier, and never have to mess with it again....! Sorry this was so long.
JimmieD |
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