1973/79 F100/150 & 1978/79 Bronco

1973/79 Ford Light Truck Parts Catalog ~ Section 40 ~ Parts List #88

WDM-CN = Ford 9 inch / 31 spline / 3.50-1 / non Limited slip

2-D6TZ-4234-A .. Axle Shaft-31 spline / Use w/ 1/2" brake backing plate bolts.

2-D8TZ-4234-D .. Axle Shaft-31 spline / Use w/ 3/8" brake backing plate bolts

Note: Ford changed the brake backing plate bolt sizes in 1979, why there are two different axles for the same application.

 

Bill, Where EXACTLY in parts list 88 does is typed 31 spline ?

I didn't see any referral at all to spline count.

Perhaps ...it is because I have the old version ?

 

I was just explaining my axle situation( wanting limited slip or trac-lock or posi traction) to a couple of guys at work, they said all ford 4x4 had limited slip, I said they were wrong, so we went out to the parking lot with packed snow, I started her up and put it in second gear let the clutch out and both rear tires were spinning, then put it in reverse and only the drivers side spun, put it in second again and hit the gas and both tires spun agian , put it in reverse and only the pass. tire spun. What kind of a set up do I have ? tag numbers are listed:
WDW CN 9EB
3 50 9 361 A

Maybe there is a L between the 3 and the 5 on the gear ratio, I will look again tonight, there is definitely a space between the 3 and the 50. It looks like this 3 50. Is there normally a space between these numbers on the tag?

 

Now it is WDW and not WDM ?

 

Sorry,my mistake, it is still WDM. I gota watch the detail, thanks Mil1ion.

 

The spline info isn't in the parts list.

I added the spline count along with the axle part numbers to assist the OP.

> > Go to parts list #88, find the axle part numbers that refer to WDM-CN.

Then go to Ford basic part number 4234 = Section 41, pages 6 & 7.

Read down till you find the correct part numbers.

Not only is the spline count given, but other pertinent info like measurements.

 

WDM-CN = Parts List # 88.

Verbatum from the Ford parts catalog:

Ford WDM (Non Locking) Service Parts List 88.

If your truck had Limited Slip originally, the axle code suffix (CN) would have been different.

Then it would fall under: Ford WDM (Locking) Service Part List 193.

Limited Slip is an option. So 2 or 4WD could be had with LS...IF the customer ordered it.

 

I am looking a NOS Detroit locker. The old box looks like a ford box with the number M-4201-D31. I would like to know if this will fit my 1979 F150 9" rear axle with 31 splines? Did Ford use Detroit locker in there 9" rear ends on the F150's if so this is likely a oem part ??

 

No ...they were Limited slip or Traction Lock

A locker is no good on the street ... It's meant for the strip

 

Subscribing ...

 

I finally got to the yard and pulled a 3rd member out of a 1979 F150 rear axle 9" with the axle code 3L50. Just for information can anybody tell me what these numbers mean that are on the 3rd member or differential. What looks like a tag with two screws reads 9A10. Stamp in the metal below this tag like thing is W-4205.

 

Million, could they have been special ordered from the factory with locker installed or would it have been a dealer installed option? I ask simply because I know of vehicles coming with what was called a no-spin rear end which I believe is another name for detroit locker type rearends. I bought one from a guy about 15 yrs ago that he said was no-spin and found that was actually a detroit locker, he just wanted to change his ratio for better mileage and I just figured I would use it someday and am running it right now to see how well it works and except for the squirllies when it resets it works quite well..

 

I finally got to the yard and pulled a used trac loc differential. It cam out of a 1979 F150 4x4 with a 9" Ford rear axle, with a tag that read 3L50. I took the center or 3rd member out, was told it was in good working order when the engine failed in the truck. I would like to know what these numbers are on the center differential. It looks like a tag is on the part, but it is really molded into the metal to look like a tag with two scews, it reads 9A10.
Then stamped below into the metal it reads W- 4205. Any help with these numbers, thanks.

 

9A10 is 79 Jan 10th date code
w-4205 could be a casting number or foundry number.