My truck, 1977 ford f150 4x4. Has torn up the rear end. The serial sticker says rear 3654. What type of rear end is that. It's a ford 9 inch,

 

Your looking at the blue certification sticker, (GAWR) Gross Axle Weight Rating, all that is telling you is your rear axle weighs 3654.

On the silver plate rivited to your driver door, it has an axle code, thats what these guys need to be able to give you info on what you have.

 

That plate is long gone. Are there any marks on the axle that identify it?

 

If it's not long gone there will be one bolted to the differential . Metal tag some times covered with grud .If it's missing you can pull the gears and get the tooth count on ring and pinion.

 

That plate is missing as well

 

Pull it and count the teeth on the pinion and ring gears, divide the pinion gear in to the ring gear ,that will be the ratio.

 

chances are that the spiders broke inside it can probably be fixed unless your gears got destroyed by the chunks of steel..... if it is indeed a 9" you can just grab another entire unit and replace the whole unit and not have to worry about it to much that way if you need info on how to change or repair never hesitate to ask its what we like to do around here is answer questions and help others with what we know so these older trucks can keep on living......

 

Look at the inspection cover on the front driving axle. Under one of the bolts will be the Ford ID tag with codes on it (if it's still there).

Whatever the front ratio is, the rear should be the same.

The rear axle ID tag was originally located at approx 5 o'clock under one of the bolts that retains the carrier (pumpkin) to the housing.

Sometimes you may find the tag under any of the bolts as people may not put it back in the same place.

But the bad news is, many people forgot to reinstall these tags while reassembling the axles, so many are missing today.