Engine Year?

[Allen9878]

I just robbed a 4.0 engine and ax15 Transmission out of a 1990 wrangler, which I do not believe was the original engine in it. How do I find out the year of the engine and Transmission ? A specific number I am looking for? Any specific place?

Thanks!

 

[Trapshooter]

Look both units over extensively and record any numbers you may find. Not sure where the S/N's are located but if you can find them you should be able to come close to finding out their age.