When I start my jeep in the morning there is a knock sound coming from the lower end of the motor(I think). I also had the same problem with my last XJ. But the knock goes away when u either have it in gear or when u rev it up. Any ideas?

 

If you have good oil pressure I would check the torque converter/flexplate.

 

What brand of oil filter are you using?

 

Good question!! I wanna know the answer. But, it would be a good idea, if you have an auto trans, to check and see if your torque converter to flexplate bolts are loose. So, let us know.

 

My 95 we got cheap because the torque converter bolts was loose.
IF it knocks and goes away shortly after starting, its typically a main knock.
Only does it till the oil pressure comes up.

 

Well my newer xj only knocks when it starts but my older xj knocked all the time no matter what the oil pressure was or how hot or cold it was

 

You haven't answered the question on oil filter brand. A cheapy oil filter can cause a little bit of bearing damage each time the engine is started until you reach the point of low or no oil pressure and the engine is shot.

Also you haven't acknowledged a very good suggestion that this Jeep probably has loose torque converter to flexplate bolts. You, or someone else capable of doing this, need to check them or you'll be paying for a flexplate in the future. Not cheap.

 

if it was a rod bearing it would get louder when you had a load on it. if it's getting quieter with load, I'm betting flexplate or valvetrain. You can get a stethoscope for like 10-15 bucks at autozone.

 

Sorry to butt in, but I searched and found this thread. I'm having a similar issue, but the knocking is now constant... If it's a rod bearing, how much to repair?

 

Got a knock too lol
but its not clanky, just sound like a deisel lol

 

If you replace the bearings yourself not much. Alot of work to do though, How loud is it and does it get progessively worse when you rev it?

If its constant throughout the rev range id look at rod bearings if I were you...

 

Loud like something's loose at first, lighter but constant while driving around 2500 rpm, started out at that rpm just before shifting at the top of first and second.

 

Sounds like something loose upon ignition, then goes away until throttling. Doesn't seem to do it all when climbing the higher gear.

 

if you've got a bearing going bad to the point you can hear it, it's time for a complete rebuild or replacement of that engine.

 

It's a rebuild that was installed 3 years ago, only 50k miles on it.