1980 f350 4x4 front axle...what is it? TTB or D60?

if its an F350 1 ton then it should be the D60 solid front axle fairly easy quick way to check would be to see if there is a removable differential cover on the front of the axle, also look to see if there is a pivot point in the middle of the truck where the 2 axle halves connect. The D60 will be a solid axle with a removable diff cover. But a TTB (D50 or D44) will not have a removable cover but will have like a bolt in third member, also the TTB axle will have a pivot point under the front crossmember. My truck with TTB front axle , Pic of Dana 60 front Hope this description and pics help ya descipher what axle you have. I know others on the forum here know actually how to read the vin code and find out what axle it is supposed to be. Also look on the differential and there should be a tag under one of the bolts that should say what kind of axle it is and what the gear ratio is.