I have an '86 d-150 with a 318/904. a problem i have is gradually getting worse and worse. sounds like a connecting rod is getting tossed around but i pulled the pan and checked all rods, lower main bearings, piston pins, upper and lower rod bearings, rod journals, and nothing wrong was found. the oil pan had little to normal stuff in the bottom and the i cut the oil filter open to find no metal shavings at all. so i went to the transmission flexplate, found that the four bolts holding it to the TC were loose, and one bolt hole has a crack and a small piece about to come apart... would a loose/cracked flexplate cause this sparatic knocking noise? it seems to get worse when i put it in Park, not as bad when its in Drive... and almost goes away when i rev the engine to 1500 rpm and higher.... Putting it in Reverse makes the truck shake pretty bad, and it makes the engine die/stall out. ANY help is greatly appreciated!! :gr_patrio
bherder
10-09-2007, 12:02 AM
I've never had it happen to me personally, but from what I've read here before, a loose/broken/tweeked flexplate or TC will cause all kinds of horrible noises and shaking.... I think you kinda' answered your own question when you say how much everything changes when you shift in/out of gear, different RPM's etc..... ;)
Jus10rh
10-09-2007, 12:06 AM
i appreciate your quick response.. im still in the "learning phase" of building engines and what not. so thanks again.
84 Ram
10-09-2007, 11:32 AM
I bought a Sport Fury Convertable some time back because the owner thought that the 383 had a bad rod bearing it sounded really bad just as you described and all it turned out to be was loose torque convertor bolts.
bherder
10-09-2007, 03:28 PM
i appreciate your quick response.. im still in the "learning phase" of building engines and what not. so thanks again.
No prob.. I guess on the bright side (Aside from having to pull the tranny labor) flex plates or TC aren't terribly expensive. Especially comparied to a new engine :D
Speed Dragon
10-09-2007, 05:35 PM
Lol I have like 6 or 7 small plates and 3-4 big ones laying under the shed out back, I sell them for like 25 bucks. They're easy to find and fairly cheap, I think a new one is like 40 something. And yeah, they can definitely sound just like a rod knock and cause all sorts of vibrations.
Jus10rh
10-09-2007, 06:28 PM
would it also make the engine die? it wasnt doing it at first but the knocking kept getting worse and worse... now its really bad... and the engine has a tendency to die for some reason. but oil pressure is good and so is everything internally. from this sound... it seems like it would be something very obvious on the bottom end of the engine...especially to stall it out. i just got a valve job done on the heads as well.
acton mike
10-09-2007, 09:01 PM
deal with the flex plate first
then methodically go though your ignition and fuel syetm
if it just quits then i would start with the electrical/ignition system
if it starts to stumble and falter before it stalls i would start my search for the gremlins in the fuel system and while I was dfoing that I would check for vacuum leaks
I do not think your flex plate problem and the stalling are related; at least i would be most surprised iof they were
acton mike
10-09-2007, 09:02 PM
deal with the flex plate first
then methodically go though your ignition and fuel systems
if it just quits then i would start with the electrical/ignition system
if it starts to stumble and falter before it stalls i would start my search for the gremlins in the fuel system and while I was doing that I would check for vacuum leaks
I do not think your flex plate problem and the stalling are related; at least i would be most surprised if they were
