Rear end decode

7173Mustangs.com

Help Support 7173Mustangs.com:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

Tnfastbk

Well-known member
Staff member
7173 Mustang Supporter Member
Moderator
Joined
Sep 13, 2010
Messages
7,772
Reaction score
307
Can anyone decode this tag. I know its a 9 inch 2.75 ratio. Trying to figure out what it came out of, etc..........

00t0t_9R3FIt06ydQz_0fl0bv_1200x900.jpg


 
Roy, I can get close to the answer. This format was adopted in 1969 and was used till the end of 9 inch production in 1986. So the date decodes as 1978, May, 4th week (8ED). The WDM-BV4 decodes as F-100 1977-1979 OR F-150 1978-1979 31 spline axles, ratio 2.79, open diff. The 351B matches the paper tag that would have been wrapped around the left axle tube, driver's side. It was used to keep things straight on the assembly line. It also identifies ratio and T-LOK or open diff. Secluff may be able to get you more information. This all assumes that my reference material is accurate. Chuck

 
According to my information, a WDM-BV4 came from a '78-'79 Ford F150 Pickup, 2.75 :1 ratio, 9 inch non-locking, 28 spline axles.

Oops, looks like Chuck beat me :)

 
Last edited by a moderator:
Hello Chuck,
Hard to add any info to anything you or Don C post. All of your posts are always thorough and accurate. The date code does verify that this particular differential came from a '78 F100/150 series truck with 28 spline axles. This housing saw duty from '73-78. The '79 version became a little more complicated with variables such as tapered roller bearing or ball bearing and 3/8 or 1/2" backing plate mount holes. The lower right, "351 B," was also the plant code.  
Nice to see something of this age with the tag still on it. It reminds me of many exasperating encounters with beat to H*ll farm trucks and clueless mechanics. They would usually bring in a box of busted parts with a burnt oil and raw sewage aroma, with no tag, serial number, or differential code off the data plate. If you were lucky, they might add that they are pretty sure it's a Ford.  '79 and prior, Ford did not use production dates on truck applications but utilized before and after serial number ranges. If you did not sell the truck when new and they don't know where it was sold originally...Good Luck!!   OK, I'm done!  :biggrin:

 
Steve, Thanks for the clarification. My WRONG reference listed 31 spline. Chuck

 
So probably not a 5x4.5 lug pattern. I'm looking for something for my rat rod. I bought an explorer disc brake rear end but after stripping all the mounds found out that the center section off set was to much for my car. So money wasted at this point and need something fast. From what I can tell some off the 1990's mustangs will work and I'm sure some granada and such also. Not real particular at this point but have to have 5x4.5 for the wheels to work.

31202.jpeg

 
Roy, It is a long read but my allow you to salvage the 8.8.  https://www.trifive.com/threads/my-explorer-8-8-install.151663/

Chuck
My problem is on the "short side". When we put it where it needs to be the caliper is way to close to the frame rails and the, for lack of better terms, quarter panel. We could modify the sheet metal but I would rather not. Looks like a 94-98 Mustang 8.8 is what I need. Found a couple but they are a little pricey for me. Thanks for looking around for information.

I got this from another web site:

1979 and newer Mustang brake facts:



- 11"and smaller brakes fit under 15"+ wheels, 12" brakes require 16"+ wheels, and 13"+ brakes require a 17" or larger diameter wheels

- 1994-1998 Mustang rear axles are 3/4" wider on each side than a 79-93 Mustang.

- 1999 and newer Mustang rear axles are about 1 7/16" wider on each side than a 79-93 Mustang.

- 94 and newer Mustang 8.8 will bolt into a 79-93 Mustang but will require brake line adapters.

- Lincoln Mark7 LSC, SVO Mustang and Fox Body Saleens use a rear axle that is 1.25" wider per side than the 87-93 Mustangs.

- 94-95 spindles share the same track width as 79-93 spindles.

- 96 and up spindles have an 8mm wider track width.

- 79-93 Mustangs all use 9" drums with 7.5 and 8.8 rear axles.

- 4.0 liter Rangers use a wider 8.8 rear axle and 10" drums.

- Explorer 8.8 rear axles are 1" wider per side than a Ranger or Aerostar with a 7.5 rear axle.

79-93 Mustangs use a 57 inch wide rear axle. 94-98 Mustangs use a 58.5 inch wide rear axle. 99 and newer Mustangs use a 59 7/8 inch wide rear axle. Lincoln Mark7 LSC, SVO Mustang and Fox Body Saleens use a 59.5 inch wide rear axle

 
We may have found a solution. By swapping both axles to opposite sides looks like it will center the differential and make it usable after all. Will know more shortly.

 
Back
Top