1987 F250, 460 w/ auto.

How do I identify the differential?

I was on the Autozone website looking for capacities and it was asking which differential I have...

Dana 60/61 w/ 9"/10.5" ring gear
Dana 60IU (w/8.8" ring gear?)
Dana 70
Dana 70HD

I can tell you the gearing is REAL low (My Dad used to use it to pull his 28' fifth wheel)

Can anybody tell me about any markings or where to find the ID?

 

The rear axle should be a Ford Sterling 10.25" axle. I believe they started using the 10.25" instead of the Dana 60 in '86 or '87. 10.25" axles have 12 bolts on the rear cover, Danas have 10 if I remember correctly. A 10.25" can be full-float or semi-float, depending on the GVWR of the truck (8600 or over should be a full-float). With a 460 in it and low gears, it's likely a full-float. You can tell the difference by looking at the center of the rear wheels. If you see the big hub sticking out with 8 small bolts going around it, it's a full-float. If all you see is the flat end of the axle flange that doesn't stick out from beyond the wheel center, it's a semi-float. The full-float 10.25" rear axle in my F350 has a Gross Axle Weight Rating of ~6000 lbs. Not sure if it would be the same for an F250. You can find the GVWR and GAWR info on the door sticker.

If the truck is a heavy duty F250 4x4, it should have a Dana 50 IFS/TTB. A light duty F250 could have a Dana 44 IFS/TTB. Dana axles have a bill of materials # stamped into thier axle tubes. I'm not sure exactly where that number is on an IFS 4x4 axle. On a straight axle it is stamped into the axle tube on iether the left or right side of the differential housing and it is a 6 or 7 digit #. That # can be looked up on the Dana website to find out exactly what axle it is. www2.dana.com/expert . On Dana straight axles, there is a model # cast into the housing on the web just above and I think to the left of the cover, viewed from the cover side. I don't know if it is in that location on an IFS axle or not. Sometimes you can find the number on the 'nose' of the diff housing, near where the pinion yoke goes in. The door sticker should also have the front GAWR info on it. It should be 5000 lbs or more for a Dana 50 IFS, I would think.

You can find your gear ratio and type of differential (open or limited slip) by looking at the door sticker that has the VIN and GVWR info. Look under the axle code section and then look up the code in the 'tech articles' section of this website, under 'axle decoders' and you can decifer the code. If the code consists of 2 digits and no alpha characters, it is an open diff. If it consists of one digit and one letter, it is a limited slip. Most F250's and F350's '87-'97 have either 3.55 or 4.10 gears.

The Dana 70 axle is typically a dually rear axle and so far as I know is only found on F350's, E300/350's and motorhome chassis. Of course just about anything is possible...

 

Actually, Ford put Dana 60's under F-250's right up until '97 or so. Just an FYI.

 

No they didn't, the only d60's used in that era were in the front of F-350s.

The 87-97 F-250s had 10.25's out back, either full or semi floaters.

 

Hmm.. Bronco Graveyard sells rear Dana 60 gears for 1980-1998 Ford trucks... http://broncograveyard.com/products/cat/20/244

I also have a copy of a catalog from a 4x4 shop that has a section in it for ID'ing axles, and it states that the Dana 60 was available in an F-series up until '98.

 

Not to my knowlege. My '92 F350 SRW has a 10.25" Ford axle in the rear and a Dana 60 in the front. Anyhow it's not hard to tell them apart if you take a look at the rear cover. I think on the Precision Gear website they have pictures of most of the popular axles, including those two. Of course they had one or two of the pictures turned 90 degrees, so if you don't already know what you're looking at, you'll have a hard time using the pic to identify the axle. Thier website is www.precisiongear.com

 

Um guys..... I think you are talking about separate ends of the truck The 60 front was in the F350 only, but I have seen 350s and a rare 250 here and there that did have a 60 rear.... maybe a special order/option, as the 10.25 was standard. As for ID'ng the front axle, a quick way to do it is to look at the top of the housing. Dana 50's have a big 50 cast in the top of the housing, large enough you can feel it with your finger (if it aint totally covered with 17yrs of grease )