Need Help IDing Rear Diff

Reply Subscribe

Thread Tools

Search this Thread

Mar 7, 2010 | 10:44 AM

XzXPatrickXzX

Thread Starter

Junior User

Joined: Jun 2009

Posts: 81

Likes: 1

Need Help IDing Rear Diff

I took my truck into work yesterday greased it up and changed the fluid in the rear diff. I seen the metal tag so I figured I would see if you guys could help me identify it. My truck is a '78 F150 351M C6. The numbers and letters on the tag go like this:
D BJ 8 DL
75 9 378 B

Would the 378 mean i have 3.78 gears? I also wrote down every number I seen on the diff housing. Let me know if you need them too. Thanks in advance

Mar 7, 2010 | 11:36 AM

HillbillyDeluxe81

Elder User

Joined: Jan 2010

Posts: 787

Likes: 0

From: Hattiesburg, MS

Actually....no. There is a "2" in front of the 75. You have 2.75 gears.

Mar 7, 2010 | 11:50 AM

XzXPatrickXzX

Thread Starter

Junior User

Joined: Jun 2009

Posts: 81

Likes: 1

im sorry i didn't see the 2, must not have cleaned it off good enough. But thanks

Mar 7, 2010 | 12:09 PM

zaaac

Senior User

Joined: Dec 2008

Posts: 226

Likes: 0

Yes, the ratio is the first numbers in the second row. The first digit is real close to being under the bolt. If there is an "L" in between the numbers it is a limited slip.

Mar 7, 2010 | 12:22 PM

XzXPatrickXzX

Thread Starter

Junior User

Joined: Jun 2009

Posts: 81

Likes: 1

I believe it is a 9 in between but ill go check after my cats get done mauling some gators. But what does the 9 mean? 9"? I can take pics if necessary.