great day goes wrong

[downhillracer]

This morning I pulled a dana 44 out of an 87', the kicker being that I got it for 104$. That was awsome. The bad part came when I was driving home and pulled off the highway and my jeep sounded like it was a diesel and then died. There is some big time knocking coming from under the valve cover. This is on a rebuilt 4.0 with about 40,000 on its clock. The motor will run but sounds horrible. Anybody got any ideas of what this could be?

 

[Tenny]

No idea, but that's horrible. Hopefully it's something stupid / small... but in all reality it probably isn't.

 

[downhillracer]

The only thing I can think of is that the oil pump went out. I dont think that I fried anything because it never went over normal operating temp. Im going to put a mechanical pressure gauge on the sending unit tomorrow to make sure that is the problem.

 

[Dustin_Z]

stripped or broken rocker stud?

 

[Jes]

First thing I'd do is pull the valve cover and take a look.

 

[downhillracer]

First thing I'd do is pull the valve cover and take a look.

Ill do that as well. Thanks.

 

[downhillracer]

Well I hooked up a mechanical pressure gauge to the oil sending unit and was reading no pressure through the entire rpm range. I dropped the pan to replace the oil pump and noticed about 20 glitter sized metal flakes mixed in with the remaining oil in the pan. I checked the rods and nothing looks to be cracked. There is no play in the rods or bearings that i can feel. Im wondering if I should put the new pump in and try running it to see if that resolves the knocking im getting in the upper part of the motor or should I check something else while I have the pan off.

 

[Harlee&Tahoe]

I'd also pull the main bearing caps and plastiguage while oil pan off.
Who re-built the engine?
I'd have been to afraid to start the engine not being 100% sure of oil pump operation.

I've always wondered if these 4.0's are an interference engine?

 

[downhillracer]

It was the oil pump. The shaft the extends out of the top of the oil pump had snapped in half right below where it meets the gears at the cam and distributer shaft. Replaced the oil pump and all is well now. No more knocking. I guess I don't have to sell off the 44 now. Thanks for the input guys!