transmission interchangeable

You noted that this is a 5.7L. I assume you meant a 4.7L?

That is not going to make much difference, but we just want to be accurate.

This vehicle most likely has a 45RFE transmission. Which means we have options but the 545RFE is going to bolt up as the internal components are the only thing different.

However, my question is why do you want to swap a different unit into this truck? There are many options for replacement transmission for not much money. This would be far better than trying to change the unit and have to mess with the TCM as well in order to get it to work as these units are electronically controlled.

If your unit is having issues, the first thing to check is the fluid because these are well known for having fluid issues causing all sorts of issues.

Here are a couple of guides that will help with this:

https://www.2carpros.com/articles/how-to-check-and-add-transmission-fluid

https://www.2carpros.com/articles/how-to-service-an-automatic-transmission

Please run through this info and let me know what the details are, and we can go from there.

Thanks

Actually it's a 3.9L.

Okay. That is going to change things because you have a 42RE transmission.

You are going to want to stick with another 42RE which came in a number of different vehicles but depending on what engine that vehicle had in it, you may have to change your bell housing. A lot of mid 1990s Jeeps and Dakota had this transmission among others.