Will 2002 Dodge Ram 1500 transmission fit 1999 Ram?

Not necessarily. While both are Dodge Ram 1500s, the transmissions used varied significantly depending on engine, transmission type (automatic or manual), and even minor model year changes within those years. A direct swap isn't guaranteed.

You need to determine the *specific* transmission code for both trucks. This code is usually found on a tag on the transmission itself. Then, you can compare them. Even if the codes are similar, there might be subtle differences that could prevent a successful fit. You should also verify the transfer case compatibility if it's a 4x4.

In short, don't assume compatibility. Research the transmission codes and consult a repair manual or a parts professional before attempting the swap.