1977 rear end needs decoding please
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JB is not part of the suffix, is separate. But, it doesn't really matter, because...
All prefixes that begin with WDM are Ford 9" rear axles without Limited Slip. The ratio as noted on the ID tag is 2.75-1
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From: Simi Valley, CA
If the OP posts the correct tag number, I can then look up the axleshaft spline count. It's a rigmarole, cuz first you gotta look up the axleshaft that matches the tag number in the rear axle parts list, then...
You gotta go to to the axleshaft spec charts and find that part number.
It could also have either the tapered roller axle bearing/seal combo, or the large ball type axle bearing, which has a separate seal.
There is no way to know which type it has, until the axle is pulled.
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My first look at the chart seemed to show only 31s for his year, ratio and "WDM". But I went back it's really about 50-50, so forget everything I said.....
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From: Wrights community
well it's been raining for the past 6 hours. I aint gonna swim to it. but pulling the axle is not one thing I want to do soon. Is there an easier way to drain the rear end fluid out? What weight lube should I replace it with?
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The only other options to servicing the rear are to either pump out the fluid or tap the case add install a drain plug. I have pumped it out and you will get ~ 85% of the fluid out by my estimates.
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WDM BR comes out to 2.75, open diff, 31 spline axles, 9" ring gear.
The rest is date and plant code.
Ford Rear Axle Assembly Identification - Page 03 - FORDification.com
The rest is date and plant code.
Ford Rear Axle Assembly Identification - Page 03 - FORDification.com
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From: Wrights community
thanks for the reply, but how can I tell which plant and the date? is there a chart for that too? The chart you posted says the rear end was built from '78-'79. My truck was built in 1976 as a 1977 model. another question I have about different rear ends, is there a chart with all the different special uses for which the rear end ratios were built for? I've been told mine is for gas mileage and minor towing. Which I have yet to see any decent gas mileage.
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The date code goes "year/month/day" as so:
6 = 1976/ J = September / B = doesn't work. Could it be an "8" for the 8th day of the month?
ON EDIT: Ford uses alpha and numeric codes in the date codes. In this case, the "B" would be for the week of the month, "B" being the second week. See the kevinstang link.
http://www.kevinstang.com/Ninecase.htm
Classic Mustang Part Number Decoding Guide
Plant code, don't know.
Does it matter?
Chart for the uses? This was just after the first gasoline supply and price shock of the '70s. 2.75s are a desperate attempt to gain mpg from a vehicle that, as you are experiencing now in the continuation of gasoline price shock, does not get good mileage.
Because your engine makes a resonable amount of low end torque, it will tow smaller loads easily.
I would not be surprised to see errors in the on-line charts like the one I listed above.
6 = 1976/ J = September / B = doesn't work. Could it be an "8" for the 8th day of the month?
ON EDIT: Ford uses alpha and numeric codes in the date codes. In this case, the "B" would be for the week of the month, "B" being the second week. See the kevinstang link.
http://www.kevinstang.com/Ninecase.htm
Classic Mustang Part Number Decoding Guide
Plant code, don't know.
Does it matter?
Chart for the uses? This was just after the first gasoline supply and price shock of the '70s. 2.75s are a desperate attempt to gain mpg from a vehicle that, as you are experiencing now in the continuation of gasoline price shock, does not get good mileage.
Because your engine makes a resonable amount of low end torque, it will tow smaller loads easily.
I would not be surprised to see errors in the on-line charts like the one I listed above.
Last edited by 85e150; Jun 3, 2012 at 09:14 PM. Reason: correct date code.
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From: Wrights community
The tag does have a B in 6JB. And thanks for the replies. I am flabbergasted at the info I have found and have been told. I am wanting to restore the truck all the way when I get the money.