Rear end question...

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Jan 2, 2001 | 08:27 AM

78 bronco owner

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Joined: Jan 2001

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Rear end question...

Just purchased a 78 Bronco. Has 351M, 4-speed and a bunch of other goodies. The rear end, however, needs rebuilt. How can I tell what gear ratio the rear end has? The tag is unreadable.

Jan 2, 2001 | 04:13 PM

bucket

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Joined: Dec 2000

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Rear end question...

You have 3.50 gears, unless someone's changed them out. '78-'79 Broncos came with 3.50 gearing, with the option of having a Trac-lock (limited slip). There is a way to tell if you have the Trac-lock via a letter in the VIN, but I do not remember how.

Good luck!

Bucket
'79 Bronco XLT

Jan 2, 2001 | 04:17 PM

bucket

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Rear end question...

Almost forgot, for '78-'79 Broncos, check out www.projectbronco.com. Excellent site - they have original color sales brochures of the '78 & '79 Bronco, plus lots of solid technical info on these rigs.

Jan 2, 2001 | 06:13 PM

hillbillyk

Laughing Gas

Joined: Jul 2000

Posts: 851

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From: Elkton, MD

Rear end question...

Try using the vin decoder on this web site, also check the front axle for a tag.

Jan 4, 2001 | 04:06 PM

bronclover

Junior User

Joined: Oct 2000

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Rear end question...

Comparing wheel revolutions and driveshaft revolutions will tell you the gear ratio in the rear end. I believe there is a tech article on this subject on this site.
Hope this helps!

1978 F150 SC 351 C6 FS-$1000
Soon to be Bronc owner!!
1969 Buick LeSabre 400
1941 Farmall "A"

Jan 5, 2001 | 05:55 AM

AlM

Posting Guru

Joined: Mar 2000

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Rear end question...

whew..what happened to the replies here?
here it is again:

http://dirtroad.com/dgr.htm

also can mark shaft and tire, and rollthe bronco forward to count the revs in reverse of waht dirt road suggests..safer!
alsp, can jack up rear (safely) and turn one wheel, if other turns, you have posi..exc, if it is worn out..this isn't a good way to check..

Jan 5, 2001 | 11:42 AM

78 bronco owner

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Rear end question...

Yeah, with the way the rear end is clunking, I don't think the the results of rotation counting would be accurate. The VIN decoder works, but, it needs an axle code. Which is missing from my door tag. The front diff. has no tag either. Looks like I'm gonna have to take out the third member and count teeth on the ring and pinion gear. Oh well, it had to come out anyway....