INTENSE VIBRATION 727 Duster!

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DusterDillon74

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Ok here we go! i just saw that tranny fluid was coming out of the bellhousing probably has something to do with the high speed vibrations!

I have already:

New mopar performance harmonic balancer 5007301
New B&M balanced flexplate BMM-10236
New Torque converter BMM-10416 Balanced
New drive shaft
tires balanced

Is there anything else you can think of
Its a 74 plymouth duster with a 360
 
Explain in detail . . . . D E T A I L

When the vibe starts, does it get worse as you ___________, does it get better if you _________ or you ______ lots and lots and lots of D E T A I L


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Fluid coming out of bellhousing not possible and still drivable. I would take a wild guess that its either the front seal or o ring on dipstick.

As for the vibration need more detail. Was motor freshly built? by you? or someone else. Is the balancer and converter both externally balanced? Is the crank balanced internally or externally? How about u joints? I see you say its a new shaft but is the rear ujoint the right one for the carrier?
 
heres a thought, assumming the ballancer is correct for a 360, then the flex plate or the convertor needs to be ballanced for the 360, but not both.
 
is it only while you are moving? or is it anytime the engine is running? xs2 on the balanced flexplate AND the converter
 
correct convertor for your crank? Longshot... are your flex plate bolts tight and not showing tracks of movement? 360 balanced convertor should use a stock flexplate or solid round B&M flexplate, not Scalloped or weighted.
 
Does is vibrate sitting still when you rev the engine up or does it only do it running down the road? I checked the numbers and the harmonic balancer is correct as is the B&M flex plate but when you say the torque converter is balanced do you mean it's balanced for a 360 or a standard neutral balanced converter?
 
if the torque converter is neutral balanced (no weights on it) then those are all the correct parts if you have a stock CAST steel crank.

if you have an aftermarket FORGED steel crank the flexplate and balancer would be the wrong parts.

if you have a cast crank and those are all the correct parts then it sounds like the torque converter is bad... dead on arrival
 
Thank you all so much for your replies. Im sorry about the detail. it only vibrates in 3rd gear drive at around 55mph and faster, its not a constant vibration more of a pulse vibration unless you slow down it will stay constant and eventually start pulsing again. so pulse on speed up constant slowing down. does not shake in 1st or 2nd. or reving

the torque conver is balanced there are no weights i assumed balanced ment no weights right?
Take a gander Torque converter BMM-10416 Balanced
So in theory my 360 is externaly balanced with a balanced harmonic balancer and balanced flex plate(scalloped) and a neutral torque conv. it should all even out correct?

Im positive its coming from the front seal but if im taking tranny off i want to try to eliminate the vibration this is where in going with this. THANKS EVERYONE!!!!

Bent axle maby?
 
you should be able to pick up a relatively cheap used sb 727 from a local salvage... then you would know if it's the tranny.

however, the 727's are also susceptible to damage if the kickdown is not in place and adjusted properly... if you leave it off or it's out of adjustment and you drive around it will fry your 727. so you want to make sure that is correct before you take off driving with the test tranny

good luck
 
Did this assembly ever operate properly? If so how many miles before the vibration began? Were all the new parts assembled at the same time? I ask because it sounds like you have been throwing parts at it to end the vibration. Also because it makes no sense to have all the new parts and then put in a leaking trans, which is easy to spot before assembly, especially if it is significant.
 
it started leaking 2 days ago the transmission runs awesome shifts on time downshifts its a good trans. eversince the car has been running it has vibrated. I want to fix this when i drop the tranny this is why i seek your help!
 
well if it is vibrating at a certian speed and above and not at a particular rpm, i would tell you it is in the driveshaft, if its like a hmmmm, hmmmm vibration. go down the road, get it vibrating and throw it in neutral, if it immediately stops, it is not in the drive shaft or rear end.
 
It's not the tc, again more detail , what happens at 60 mph? and 65 mph ? what happens and the feel at 70 mph?

Forget the tc , did you change your original gear ? and what are and were?
 
73AbodEE said:
well if it is vibrating at a certian speed and above and not at a particular rpm, i would tell you it is in the driveshaft, if its like a hmmmm, hmmmm vibration. go down the road, get it vibrating and throw it in neutral, if it immediately stops, it is not in the drive shaft or rear end.
Click to expand...


Thats not always true, i have balanced many shafts when they are under drag they lose the harmonic issue and only have them at slight power/cruise. . .

especially the harmonic sound type vibe.
 
you have to start somewhere, and if it were me , i would try that first. i had a vibration while moving and above 50 mph. i have a harmonic type drive shaft from a 86 chrysler le baron, i would throw it in neutral and it would keep on vibrating, not as much, but none-the-less, it was there, took my shaft in, they re-balanced it, problem solved.
 
73AbodEE said:
you have to start somewhere, and if it were me , i would try that first. i had a vibration while moving and above 50 mph. i have a harmonic type drive shaft from a 86 chrysler le baron, i would throw it in neutral and it would keep on vibrating, not as much, but none-the-less, it was there, took my shaft in, they re-balanced it, problem solved.
Click to expand...



im not saying he doesn't have a shaft issue, i believe he has a issue with the shaft, im saying to you....

IT is not always the case that when you drop it into nuetral and the vibe goes away that you are ruling out the shaft, i have balanced many shafts that will do that and are the problem with a very specific rpm of issue and the second it changes its gone.
 
I just had one here that vibrated and then starterd to leak. The torque converter was wrong for the motor balance. . The vibration caused the converter to crack at the hub weld. My son took the weights off of the converter and tig welded the hub. No vibrations and no leaks. customer didn't have the funds for a new converter so he left happy.
 
i just got off the tele with B&M they said i have the correct set up from harmonic balancer to the TC i will try the drive shaft again i suppose. this is kicking my *** im tired of messin with this thing!
 
Does sound like a driveshaft to me too. Maybe when they balanced it last they didn't get a weight welded on good and it tossed it right away?? Just a thought. And don't assume all leaks from the front of the trans. are the front seal. I've seen just as many leaks come from other things such as the dipstick tube (runs down the bellhousing and looks like a front seal leak), the large O'ring on the perimeter of the front pump can leak. The 1/4" pipe plug that holds in the front band mounting shaft can leak if not sealed properly and last but not least a cracked torque converter can leak. Pull the dust cover and inspect it good before you pull the trans. and you might save yourself some work. Good luck
 
there was another thread here where someone had bolted on some rims, and one of the balance weights on the rear drum was interfering with rim just enough to cause a slight wobble with the wheel causing a vibration, and another where the trans mount was about to come apart, and once replaced, the vibe was gone. im just throwing ideas out there. vibrations really suck. there was another where a guy had a slight bubble in one of his tires...
 
73AbodEE said:
and another where the trans mount was about to come apart, and once replaced, the vibe was gone.
Click to expand...

I encountered that with my Dakota too.

Vibration at certain speeds, wouldn't do it all the time.

I crawled under the truck to check the u-joints, and when I grabbed the driveshaft to give it a tug.... I lifted the transmission up off the crossmember! :eek:ops:

The mount was so bad, that it was no longer holding the transmission to the crossmember at all, just free floating wherever it wanted to. I guess the fact that my transfer case shifter bounced around like a toddler on a sugar fix, that should have been a huge indicator that my mount was bad :D
 
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