Rattle noise from bellhousing on my LT1/T56....
04-07-2008, 06:37 PM
#1
Staging Lane
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Rattle noise from bellhousing on my LT1/T56.... Ok I really need some help here. I have had my LT1/T56 combo in my Datsun 280ZX for a couple of years now and I have had this noise since day one of the swap. The noise is coming from the clutch area. Its sounds like a rattle / knocking noise. The noise goes away when I push the clutch in and I can only hear it when the car is at idle and the clutch pedal is out. It is very annoying to say the very least. Here's what I've done...
*2 different clutch set ups 1) center force dual friction 2)SPEC Stage 3
*2 different flywheels (one with each clutch)
*pulled motor and inspeceted mains and rod bearings(all within specs)(motor was fresh rebuild before installing into my car).
*transmission rebuilt with new bearings, syncros, billet keys, steel shift fork, and seals. No shafts were found to be worn out. No broken pieces found inside tranny either.
*3 different pilot bushings...2 factory and one aftermarket ones.
What could it be? Should I try a new clutch fork? That's not new but it felt tight on the throw out bearing when I tested it on it before installing the tranny this last time. What about something hydraulic? I am using the stock f-body hydraulics(inluding the pedal assembley).
I have search but didn't find anything. Someone save my day! LOL
Guy
*2 different clutch set ups 1) center force dual friction 2)SPEC Stage 3
*2 different flywheels (one with each clutch)
*pulled motor and inspeceted mains and rod bearings(all within specs)(motor was fresh rebuild before installing into my car).
*transmission rebuilt with new bearings, syncros, billet keys, steel shift fork, and seals. No shafts were found to be worn out. No broken pieces found inside tranny either.
*3 different pilot bushings...2 factory and one aftermarket ones.
What could it be? Should I try a new clutch fork? That's not new but it felt tight on the throw out bearing when I tested it on it before installing the tranny this last time. What about something hydraulic? I am using the stock f-body hydraulics(inluding the pedal assembley).
I have search but didn't find anything. Someone save my day! LOL
Guy
04-07-2008, 09:45 PM
#2
wrencher
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Is the fork tight to pivot on the trans witht the retaining clip built into the fork?
that's the only thing I can think of that could be your problem.
Maybe put a spring extenal on there just for diagnostic purposes to keep the fork tight against the pivot & see if it cures the problem?
that's the only thing I can think of that could be your problem.
Maybe put a spring extenal on there just for diagnostic purposes to keep the fork tight against the pivot & see if it cures the problem?
04-08-2008, 08:15 AM
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It could simply be a clutch "tune" issue. Production clutch springs are tuned to address the the neutral rattle that is common in manuals. Aftermarket clutches do not go through the extra work to refine the neutral tune. If you are sure the throw out bearing and fork installation are not causing this, a production replacement clutch disc may help.
05-26-2011, 01:28 PM
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Did you ever find the problem? Mine started this last year before I parked my car. As you can see I have an ls6/t56 in my FD. I pulled the motor and tranny. MS3 cam and new heads went on. I rebuilt my tranny and found my reverse synchro keys poped out the slider and the retaining plate also popped off. I fixed everything and put it backtogether. I'm about to put it back in my car and I figured I fixed the problem. I just want to know what your issue was or if that clutch tune was the problem. I also have the ls7 clutch and flywheel in mine. Thanks guys
05-26-2011, 06:03 PM
#5
dont know about the T56 in your ls6 combo but the T56 for 94-97 were notorious for haveing the "marbles in a can" sound while in neutral, clutch out and then the noise goes away when driving or clutch depressed...in other words the OP's problem was quite possibly "normal"
dont know if this applies to your situation.
FWIW when I bought a new T56 from D&D who did some upgrades (billet syncro keys, steel 3-4 fork) and I installed in a A4-T56 swap I started it and WTF when I heard that sound. Called them and with a smile they said normal. Sound did diminish as tranny broke in some. Redline D4 fluid also helped but I still use dex3 since synthetics may not work well with blocker ring material in tranny.
dont know if this applies to your situation.
FWIW when I bought a new T56 from D&D who did some upgrades (billet syncro keys, steel 3-4 fork) and I installed in a A4-T56 swap I started it and WTF when I heard that sound. Called them and with a smile they said normal. Sound did diminish as tranny broke in some. Redline D4 fluid also helped but I still use dex3 since synthetics may not work well with blocker ring material in tranny.
