Brett...I've attached a .pdf of a partial transmission code cross-reference compiled by John Glancy of Scout light line/Super Scout Specialists, inc. This doc is also available on the sss website. It contains the most common transmissions used in light duty IH applications, but is only a small part of the big picture regarding all transmissions used on all ihc motor vehicles. This listing is about one-fourth of all transmissions used throughout the entire production system over the years.
The model is the "t" designation which is the commonly-refred to identification method. The five digit "code" is the internal reference number used by ihc regarding callouts for each component used to make up an entire spec'd vehicle at the point of assembly. Those codes are what appear on the lineset ticket and were the primary means of identifying "which" component was installed on any particular vehicle once it left the assembly line.
Once the vehicle arrived at the delivering dealer or fleet's point, if any changes were then made in equipment or additional items added, they were penciled in and a report made back to IH corporate so that their copies of the lineset records could be updated. Of course, this did not always happen, but in many cases folks have original linesets with "penciled" notations made at the time of vehicle delivery or dealer-installed option installation.
Every dealer had microfilm (later microfiche) copies of all linesets generated every year of production, they were most times a must-have in order to be able to positively identify what parts might be used on any one vehicle. Vehicles moved around all over the country and the end user could not be depended upon to have and keep a copy of the lineset for parts I.d. When called upon.
When a new vehicle was delivered to the dealership, part of our "pdi" (pre-delivery inspection) process was to checkoff and make a positive id of all items shown on the lineset ticket. And if a vehicle was ordered with a "transmission delete", then we had to verify that indeed...no transmission was installed...see model/code t-29/13029!
So by looking through this matrix, you can answer your question and determine the relationships amongst all these "codes" we throw out all the time!
Making a positive I.d. Of many borg warner transmissions can be difficult. The same shifter top was used on many tranny cases...so the designation that is cast into that housing is not used for positive I.d.
My opinion regarding your tranny, rebuild it if needed! There is no advantage to a synchro 1st gear unless you are doing alotta towing at max gvwr in hilly terrain where it's necessary to use 1st gear much of the time. And with some practice you can shift into non-synchro 1st with no clash.
Wide ratio is the "granny" low gear version, the first gear set is much larger in diameter/tooth count. For positive id, either count the output shaft revolutions compared to input shaft, or simply pop the shifter top off and look inside, the 1st gear on a wide ratio is big!
