Hey guys,
Ive been trying to id my rear axle and third member as Ive blown the diff...its locked up tight.
The door tag ID's the rear axle as a type 14J...I know its a 9 inch 28 spline but does any one know from the id if its a 3:1, 3.25:1, or 3.5:1 ratio?

TIA....Thomas

 

3.00:1 ratio, open (single track) differential.

 

Not that I dont trust your info but may I ask where you got the info?
Thanks by the way.

 

Ancient Chinese secret.

The following link list numerous Dentside ratios/ratio codes.

1973-1979 Ford Truck VIN Tag Codes (Rear Axle) - FORDification.net

 

I just realized when I read the descriptors again that the "J" was the front axle code...."D.A."....Thanks again.

That link was the same one I was going by...

 

"J" means your truck came with power steering. The "14" is, like ultraranger said, is a Ford 9" 3.00:1 non-locking differential. This info is from the Ford parts catalog.

 

Quote:

Originally Posted by Colo76F150SC

Hey guys,
Ive been trying to id my rear axle and third member as Ive blown the diff...its locked up tight.
The door tag ID's the rear axle as a type 14J...I know its a 9 inch 28 spline but does any one know from the id if its a 3:1, 3.25:1, or 3.5:1 ratio?

TIA....Thomas

Quote:

Originally Posted by ultraranger

3.00:1 ratio, open (single track) differential.

Quote:

Originally Posted by mikeo0o0o0

"J" means your truck came with power steering. The "14" is, like ultraranger said, is a Ford 9" 3.00:1 non-locking differential. This info is from the Ford parts catalog.

Thanks Guys....am I reading it right that it has a 28 spline axle? Just want to make sure.

Also....is there a differential ratio I can get into without modifications for a 4.??:1 or 5.??:1 ratio....the 3:1 diff is great for the highway but kinda sucks in the city, light to light where I do most of my driving (90%).

 

With a 3600# rating or greater, I would guess it to be a 31-spline axle. Only way to know for sure would be to pull an axle and actually count the splines.

If you can find a truck with 4.11s, you could swap third members. You would just have to be sure the differential spline count matches the spline count of your axles.

4.11s are going to suck on the highway, without an overdrive.

 

Thanks...yeah I know a 4:1 will be nasty on gas, redeuced top end, etc. on the highway...but 90-95% of my driving is in town not on the highway...Im using my truck as a daily driver and for now thats mainly light to light where the 3:1 suffers.

ALso...if the axle tag is in place on the truck( i honestly havent looked yet) would it tell if the axle is a 28 or 31...?

 

Not directly. The first string of letters/numbers on the upper left side of the rear end tag will tell you what parts to reference in a master parts catalog.

 

Ok Thanks again. Now...wheres my ratchet?

 

Actually it will, with the Ford parts catalog. In the section for rear diffs. You look up the code on the axle tag. The parts catalog will tell you which parts list to use. You go to that parts list and see which axles it calls for, then you go to the axle section, look up that part number in the axle specs and there it will tell you whether they are 28 or 31 spline versions.

 

That's what I was saying. Just looking at the tag, it won't tell you what the spline count is without first looking up the alpha-numeric to cross-reference what the tag code translates to, in terms of what the actual parts are in the rear end.

Just to look at the rear end tag though, it won't be stamped with "28" or "31" for the axle spline count.

The 3rd member in a truck may not be the one that came in it from the factory. Someone could have changed it (and the axles) out from something else. The tag could be missing if someone messed with the 3rd member and didn't bother to put the tag back on. It could even have a tag on it that someone just stuck on it from something else that doesn't even match what's actually in the rear end.

The sure way to know what you have is to pull the axles and count the splines and the only sure way to know what ratio you have is to pull the 3rd member, count the number of ring gear teeth and the number of driving pinion teeth then, divide the number of ring gear teeth by the number of driving pinion teeth. This will tell you exactly what ratio you have.

 

I wouldnt go so extreme with 4.11s, 3.50 or 3.70 would be a better middle ground

 

I was actually sitting here thinking the same thing...Ive put out some feelers for a 3rd member in different ratios...we'll see what turns up...Im missing my truck bad though.