The tag says: V 420 F
73 10 5 5E09

It's been painted so I'm pretty sure that's it.... Someone told me if I get different rear end I could get some better fuel mileage so I was just curious about what one I even had but couldn't find anything on it

 

I think it says you have 4.20 gears in there at the moment (if they are original) what RPM's are you turning at 70 MPH?

Just bear in mind, if it is a 4x4 you will have to swap out both front and rear gear sets.

These rears are a 10.5" sterling also, front will either be a Dana 50 or 60

 

When I bought the truck, the guy said he put a rear end in from a junk yard cause something happened to the old one... If it is a different one then my front for 4x4 what will happen?

 

They will both be turning at different speeds when 4x4 is engaged. If this is done on a surface that won't allow the tires to slip (to account for the different speeds) then you are putting your driveline in a bind and will probably end up breaking something.

Hopefully he had the foresight to either change out the old axle for one with the same gear ratio or he switched out the front to match?

 

I don't think he did... Because I had to use my 4x4 only one time and when I did it was acting kind of jumpy like my front was spinning faster then my back.... So can I just change the gears in my rear end to Match or what needs to happen, sorry I'm completely new to this whole thing

 

Here is a VIN decoder for the trucks. Axles by VIN are a little over 1/2 way down the page. That will tell you what the truck was made with, if you're lucky the front hasn't been changed out and you can just get the gears to match it for the back end.

Super Duty Identification Codes

 

That's nothing to be sorry about. Welcome to FTE, these guys will steer you straight.

 

Okay, I'll check as soon as I get back to the house! Thank you guys a lot!

 

See if there is a tag on your front diff housing too.....

And as mentioned, it isn't problem, without the awesome guys here I would still be in the same boat as you!

 

V420 f , is the code that it came out of a truck
73, is the ratio look closer there is a 3 missing so you have a 3.73
10 5 is the ring gear size
5E09 is a date code ( May 9th 1995 ) edit...or 2005

 

Attached is the Axle Specification and Information. You can obtain the letter from the Door Build Sticker.

However, if, in fact, the rear was replaced, the only "sure way" of knowing is to remove the gear and determin the ratio using the Pinion and Ring Gear.

 

It's 2005 because the 1990/2001 Ford Light Truck Parts Catalog has no listing for V420-F

 

That's what threw me off, I guess that explains it! Learn something new every day!

 

Count how many turns the driveshaft takes before doing a complete turn on the wheel. That should give you a close estimate as to what gears you have.

 

So the rear end came out of a 2005? Okay I will first thing In the morning check on that... Thank you!