lionel 2343 f units variations

Geopeaks: Pictures would really help here. From what you've said, you very likely do not have a genuine Postwar 2343 AT&SF unit. For one, there is no bell on a Postwar 2343 and there would definitely NOT be a switch under the front truck to lock-out a reverse unit.

My guess, is you have a Lionel Modern era re-make of this iconic diesel set from Lionel's past.

This likely dates it from somewhere newer than 1990 production.

lcru could be ACRU - AC Reverse Unit made by QSIndustries. That was the fist successful electronic [printed circuits] reverse for 3-rail "O" Gauge trains. It was made in the early- to mid-1980's. It was designed for Lionel Electrical Operating Standards and postwar transformers. It was quiet and reliable. Sound systems that plugged into that board came later. Somebody probably replaced the Lionel E-unit in that 2343 with an ACRU.

Photos really would help with this one if possible.

Geopeaks, does your F3 have die cast trucks and frame?  Also does it have dual pullmor motors or DC motors?

 

dual pullmors and magnatraction and die cast trucks and couplers