Tag - 3rd Member: 1973 F100

Clutch, transmission, rear axle

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SemperFi
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Tag - 3rd Member: 1973 F100

Post by SemperFi »

Hello, i was looking at replacing the 3rd Member on my 1973 F100.
the Tag
Line 1: WDM-BY4 7JD
Line 2: 75 9 3 5or9 1 B

the rearend ID here http://www.fordification.com/tech/rearends_ford03.htm
says the following.
Ford F100 Pickup '77-'79
Ford F150 Pickup '78-'79 2.75 9 in NL 28

Could this not be the original 3rd Member ? if so, what would be compatible ?

I may have found it, http://www.fordification.net/tech/vin_axle-rr.htm shows that VIN tag and its 17j


Thank you for your help.
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DuckRyder
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Re: Tag - 3rd Member: 1973 F100

Post by DuckRyder »

Actually I don't see BY4 on that list... BV4 yep, BY2 yep, BY4 nope...
Robert
1972 F100 Ranger XLT (445/C6/9” 3.50 Truetrac)

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sargentrs
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Re: Tag - 3rd Member: 1973 F100

Post by sargentrs »

I replaced the 8" in my '64 Fairlane with one from these guys http://www.quickperformance.com/Complet ... c_558.html Drop in replacement and fit and worked perfectly. Your choice of gear ratio and for under $500 for a standard open carrier you cant beat it. They build to order so might take a couple weeks depending on backlog.
Randy
1970 F100 Sport Custom Limited LWB, 302cid, 3 on the tree. NO A/C, NO P/S, NO P/B. Currently in 1000 pcs while rebuilding. Project thread: http://www.fordification.com/forum/view ... 22&t=59995 Plan: 351w, C4, LSD, pwr front disc, p/s, a/c, bucket seats, new interior and paint.
1987 F-150 XLT Lariat, 5.0/C6 auto.
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Re: Tag - 3rd Member: 1973 F100

Post by harlan »

I also have a problem finding what third member I have in my '78 F-100. It is equipped from the factory with the 400M engine, C6 transmission.
The tag I found on the third member is 7HD DM 8J and 387B. No where in the listings for the Ford third member have I seen anything close to these number/letter combination.
Anybody have a clue what I have?
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Ranchero50
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Re: Tag - 3rd Member: 1973 F100

Post by Ranchero50 »

I don't see where it matters a whole lot. Pop an axle out and verify the spline count and measure the yoke to make sure you get the correct U joint and go junkyard shopping for the axle ratio you want. If you want the same ration, pop yours out and check it first. 9" is taller than wide, 8" is wider than tall.
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