My 1998 Jeep Cherokee Sport is making a knocking noise from the engine. The noise gets worse when Im going down hill. In fact I dont really hear it when going uphill. Any ideas?

 

The first thing to check would be the torque convertor bolts or the flexplate, that is if you have a auto trans. Pull the inspection cover off of the bell housing and check the bolts that attach the torque convertor to the flexplate to see if they are loose. If they are then remove one at a time, clean them, reinstall them with some Locktitie and retorque to the proper specs. While you have the cover off check for cracks in the flexplate.They are prone to cracking and creating a knock that can fool even the most knowledgable mechanics into thinking the bottom end of the engine is going bad. The tell tale sign is your description of how it gets louder going down hill. When accelerating the flexplate has a load on it that will keep the loose or broken pieces lodged together. When idling or coasting the load is reduced and will allow the flexplate to move enough to cause the knocking sound.

 

/\ me too.

 

I took it down to the shop this morning, and it turns out you were right. The flex plate was broken. Thanks, you saved me alot of money on labor.