what are the differences between pt and ft cases. I have a np203 with locking hubs and i don't know if its pt or ft. Its my understanding that the full time have a differential but thats about it the my understanding.

 

ok aftering some net searching the full time is like all wheel drive but its awalys in 4wd then. I have a np203 its not in 4wd until the wheels lockouts and lever are in postion.

 

"Full-Time" and "Part-Time" are used in a couple different senses.

One sense refers to a 4wd "mode"; in that sense of the word, you're right, "full-time" 4wd mode is like AWD, in that it uses a center differential to allow driving on both low and high-traction surfaces (hence "full-time"). "Part-Time" 4wd mode locks the front and rear outputs together, and can't be driven all the time (hence the "part-time" name).

Your NP203 has both modes.

Another way the term has been used refers to the transfer-case itself. If a transfer-case has a 2wd position, it would be called a "part-time" case (because it's only in 4wd part of the time), and those with only 4wd modes and no 2wd would be called "full-time" cases (because it's in 4wd all the time). In that sense, your NP203 is a full-time case.

A transfer-case might also be designated by the primary 4wd mode it is designed to use. Thus, since your "normal" 4wd mode on an NP203 is a full-time mode, it would be called a full-time case.

Confusion over these different senses arose because in the 70's, all three senses of the word applied to the "full-time" cases available in vehicles (NP203 and BW1339) while all three senses would apply to the "part-time" cases (D20, NP205, etc).

Things got confusing in the 80's when manufacturers created cases with a 4wd full-time mode and a 2wd mode. Depending which sense of the word you use, it could be called a full-time or a part-time transfer-case.

Your NP203 is definitely a full-time transfer-case, though, which happens to have a part-time 4wd mode.