lizard_king15

Ok, this is the car I mentioned in an earlier post that I had win off ebay. The problem(or maybe the good thing)is that the car once in gear(and sometimes when not in gear after ripping around?!)pounds so hard(while sitting) that i can feel it in the floorboards. it gets faster and then stops until i stop revving. Setup is a Dynamic S/S c-4 3spd with 3000RPM stall aluminum driveshaft, Eaton Posi and 3.73s. Was ok with it till I got home for tearing around and the "thump" was still there in park and nuetral. Please help me worry...Or feel confident in my bada$$ness lol. and FYI I haven't even touched the nitrous yet lol, but this is the fastest stang ive ever been in. I have BfGoodrich DOT drag radias 255sumtins and it will just eat em up if i try to take off too fast...as in i sit there for 10 seconds or until i let off throttle and spin. Thanks

Quik

what do you mean thumping or pounds so hard

nemethjames1

you mean the engine idles rough??? be more specific in symptoms

lizard_king15

there is a pounding...not metal to metal or anything like that just feels like a rubber mallet hitting floorboard when I'm at idle. like every revolution the torque converter makes befor 2K it "thumps" "jerks" whatever you wanna call it. I i know its not the motor cause it idles smoothly and it goes away once i start driving. Also if the motor was as rough as this It probably wouldn't be runnin. Now I'm pretty sure this is normal for my setup but what scared me is it was still doing it today even in park andt Neutral. the car doesn't jerk around or anything just that. So I guess my question is...Does anyone else with a high stall or a high stall and C-4 experience this also?

Quik

well i got a 3k stall with my aod and dont have that problem. something seems outof balance. sorry i cant be more helpful

nemethjames1

whatever it is i'd bet it dont belong

lizard_king15

see the crazy thing is it doesn't effect anything while driving/moving. of course when im going 20 in third it does it a lil cuase im under 1500RPM but once i get going it shifts accelerates and feels smooth as a baby's bottom. thanks for the input but i think I'm gonna do the ol' "pull and pray[:-]"...as in I'm going to act like nothing happened and hope she...I mean it... doesn't come back to haunt me. Oh and FYI the C-4 is like a 3rd of the size of an AOD.

roundman

just for grins I would pull the inspection cover on the front of the bellhousing and check the tightness of the torque converter bolts to make sure it ain't coming loose. use some red loctite on the bolts and torque them down to specs. also check to make sure the bellhousing to engine bolts are good and tight and the tranny is fully seated on the dowels at the back of the block too. while you're under there, take a look at the motor mounts and tranny mount and see if they are OK too.

vfast

I think he has a mount gone or is crack badly..

roundman

is there an echo in here? didn't I just say that???