Yes you can but the one from the 89 is rated for less torque than the one that you are replacing. So it may not last long depending on what you are hauling.

 

28 foot 5th wheel, so probably not a good idea is what your telling me?

 

The difference is that the ZF5-42 is rated at 420 lb/ft of torque, where the one in your 97 is rated at 470 lb/ft. The one from the 89 is 8 years older than the 97, so what could be wrong with it?

If it was me I would find a shop to rebuild the one from your 97. Odds are you will be into it for a few more dollars with a better transmission.

 

Thank you for the info

I'll get it rebuilt