Shaner Posted February 11, 2008 Share Posted February 11, 2008 Hi there fellow HybridZ'ers. My name is Shane and I've been searching the forum for about a year now or so. Didn't feel the need to sign on yet as I've found answers to all my questions using search, until now.... Background... 74.5 260, dropped 1 inch, poly bushings, Bad Dog frame rails, 85 Chevy 305 freshly rebuilt with stock heads, MTC1 cam, stock exhaust, Weiand Action Plus intake, HEI dist, Edelbrock 1405. 85 700r4 freshly rebuilt w/2000 stall, B&M shift kit, Brake light activated lockup Stock R180 Diff. And here's the issue I couldn't find an answer to in the search: In between 2000 rpms and 2500 cruising in top gear I get a knocking sound. The sound does not occur during mid throttle or wide open acceleration. It sounds almost like a duramax desiel does under hard acceleration with the knocking. I've adjusted the timing and swapped jets out to see if I could alter or get it to go away...no dice. I get a steady 5.5 psi all the way through so I don't think it's fuel related. Took it out last night and got it up to speed on the highway, shifted to neutral and in neutral the knock still showed up at 2000-2500 in neutral at speed. As the problem is right at the RPM range for the stall coverter, does this sound like the new stall conv is going out? I've noticed the pickup in 1st gear is dropping off slowly but until last night I figured it was a tuning issue, now I'm not so sure. I called the tranny place and got a "I've not heard of my stall coverters going out but you can bring it in..." response. Spent the weekend checking valves, timing and jetting. Couldn't get it figured out and am looking for ideas. Anyone heard of a stall covertor knocking like a bad pushrod only at a specific rpm range? I've spent most of the past year working on the conversion and am getting very close to being done. Thanks for any ideas! Quote Link to comment Share on other sites More sharing options...
HICKL Posted February 11, 2008 Share Posted February 11, 2008 Can you isolate which end of the car the sound is coming from? I have damaged a few rear differentials and picked up some strange noises from them. Is it a consitant knock or an intermitant clunkity clunk? Jeff Quote Link to comment Share on other sites More sharing options...
Shaner Posted February 11, 2008 Author Share Posted February 11, 2008 It's coming from the rear engine/tranny area. I havn't been able to get the car up and test with a scope yet for weather. I first thought it was maybe piston slap or a bad bearing. But it only happens in that rpm range. I've got a brand new Jegs Heavy duty 168 tooth flexplate. It sounds like its coming from either the front of the tranny or the back of the motor when listening to it at speed. I can't reproduce it in neutral or park when stationary. I'm pretty sure it's not U-joints or the diff mount(been there done that:-P) Quote Link to comment Share on other sites More sharing options...
jt1 Posted February 11, 2008 Share Posted February 11, 2008 Double check all the flexplate bolts. jt Quote Link to comment Share on other sites More sharing options...
Shaner Posted February 11, 2008 Author Share Posted February 11, 2008 Thanks JT, I'll check them. Would that cause a sound only at specific RPM? Quote Link to comment Share on other sites More sharing options...
jt1 Posted February 12, 2008 Share Posted February 12, 2008 Maybe, maybe not. Chasing a drivetrain noise can be tough and frustrating. Sometimes they don't originate where you think, and it's just a process of elimination to find the source. However, based on what you said, the flexplate would be the first place I would start. John Quote Link to comment Share on other sites More sharing options...
Shaner Posted February 12, 2008 Author Share Posted February 12, 2008 Thanks John, As soon as I can get under the car I'll check it and post back what I found. Quote Link to comment Share on other sites More sharing options...
Shaner Posted February 19, 2008 Author Share Posted February 19, 2008 Thought I'd follow up. I got the car up and unbolted the TC. Gave it a spin and got a clicking in one spot as it went around. Bolted it back in and tried a test drive. No gear at all. I think either the pump or the TC is out. Luckily I have a warranty on the rebuild so it's back to the tranny shop. This time they can pull it out. Thanks for the suggestions and JT, FYI The flywheel bolts were good. Thanks for the help everyone! Quote Link to comment Share on other sites More sharing options...
Administrators BRAAP Posted February 19, 2008 Administrators Share Posted February 19, 2008 Please post a subject title befitting your question or topic of discussion. Vague pointless titles only serve to muddle up the data base when others use the search function. Please read this link in its entirety, including #3; Click ME and please read. Thank you, Paul Ruschman HybridZ Staff Quote Link to comment Share on other sites More sharing options...
Shaner Posted February 19, 2008 Author Share Posted February 19, 2008 Will do Braap. Thanks for changing the title. Quote Link to comment Share on other sites More sharing options...
Shaner Posted April 28, 2008 Author Share Posted April 28, 2008 Wanted to close this thread out with an update. Seems like a multiple failure. Tranny oil pump went out. Also found 2 rods out of tolerance on the lower end. Pulled them all out and had them repaired. Also found the ignition module was installed incorrectly at the factory with wrong hardware causing the distributor to cut out causing a knocking. All repaired and knocking is gone. On to the next issue....... Sometimes with this project I feel like Danny Glover at the end of Predator 2......Who's next? Who wants some? Thanks for all the help!!! Shane Quote Link to comment Share on other sites More sharing options...
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