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Almost convinced I have a flexplate knock

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Posts: 231
Joined: June 15th, 2014, 6:55 pm
Stroker Displacement: 4.6
Vehicle Year: 1990
Vehicle Make: Jeep
Vehicle Model: Wrangler

Almost convinced I have a flexplate knock

Post by optmaxx » May 8th, 2019, 1:13 am

I've had this knock that (it's more like a tick, but I'll call it a knock) only appears a little bit after my YJ has reached operating temp, and it's more noticeable between the engine and transmission. I brushed it off after being told that it's more likely the flexplate by a few mechanics that put a quick ear to it, but then I got a little worried thinking that it could be something else like cam-walk, but I wasn't too sure about that cause I used a stock aftermarket cam for a 95 4.0, and all of my oil changes showed no signs of any metal pieces or flakes.

I took a mechanic"s stethoscope to it and put it to certain areas like all over the oil pan, valve cover, the area on the block where the cam would be, the timing cover, the area between the engine and trans where the oil pan strap is and I didn't hear anything that sounded like the knock; just the sound of moving mechanical parts. So, I put it to the bell housing and the knock was definitely there, and in better detail.

The knock is louder on (with the stethoscope) the bottom portion of the bell housing, and even a little behind it like where the flexplate and torque converter would meet, and I think it's more distinct on the driver side of the bell housing for some reason. However, I can't see any signs that my flexplate is hitting something within the bell housing, so maybe it's warped? I did use blue loctite on the flexplate bolts, but I did reuse my old Autozone flexplate and the original back plate which I probably shouldn't have. The torque converter has never been changed as far as I know, and my Jeep is a 1990 YJ.

I'm kind of convinced that it's a flexplate/torque converter issue, and I guess I won't know until I swap one of them out, but could the torque converter make a knocking sound too? This video I found sounds like the knock I have, but the noise is confusing to me cause it doesn't sound like a typical flexplate knock, but I guess I'm not familiar with every noise a flexplate or torque converter can make. Can they make a sound like the one in the video? I might put in new flexplate bolts to start with, and I also lost the inspection cover so I'm wondering if putting one on will muffle the sound to where it doesn't bug me. The noise seems to bother me only, so maybe I'm listening too hard ha ha.

Video: https://www.youtube.com/watch?v=318aR4I ... ex=11&t=0s

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