i have a 72 duster that used to have a slant six and now has a 360. all of the major suspension parts came out of a 73 dodge 340 car in cluding the rear end, k frame, strut rods,transmission, and brakes. i have now completly replaced all of the front end peices and rear leaf spirngs and u joints. the new front end peices include, tie rod ends, brake calipers, roters, ball joints, swaybar links, idler arm, pitman arm, power steering box. i have unilug rims all around with brand new tires, the front end was allinged twice because the first people messed it up and the front tires were replaced each time. i have taken the wheels off multiple times to make sure they are centered. the problem im having is that after about 5 min of driving on the highway a horrible vibration starts and the steering wheel shakes and it feels like the wheels are comming off then when i brake to slow down or get off the highway the vibrationg gets worse and the vibration can be felt in the pedal but once i stop and start to drive on the normal road the vibration goes away then once i get back up to 40 the vibration comes back but before i got on the highway it was not vibrating at 45mph. i hope i gave enough info any help would be great. i have replaced every thing now.
highway vibration
- Thread starter duster-z
- Start date
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Get under the car again and double check every nut, bolt, etc. Something major is loose....be careful.
pettybludart
Well-Known Member
Maybe it could be your torque convertor?Does it have a little weight on it(360 external banced crank needs the convertor with weight)
the engine was internaly ballanced at the machine shop with a b&m flex plate and i took all of the weight off of the converter to make it neutral balanced but the converter might be over 30yrs old
SRT_DSTRHOLC
Well-Known Member
I think I have the same thing...does it make a sound also when you get around 40mph? I wonder if its the driveshaft. Im rebuilding the front end to see if that helps any.
Mopar to ya
Well-Known Member
I bought my 318 Dart and had the same problem. I checked the converter and found an external weight. 318's are internally balanced. I changed to a 2800 stall converter and the vibration went away. Taking a weight off a converter does not make it neutrally balanced any more than taking the weights off your wheels neutrally balances them. The weight balances any manufacturing or machining issues that were already there. Now it is unbalanced. I would certainly consider a new converter, and since you are already there, go with a nice stall.
today i thought to check if it was vibrating when parked and sure enough at 3000 rpm it started vibrating could this still be the torque converter? i also realised i reused the harmonix balancer could it cause similar vibrations like the wheels are comming off thanks for all of the help so far.
If the vibration starts only after driving a while it could be a stuck caliper!
:salute: mopar373
BillGrissom
Well-Known Member
The 5 minute delay is strange. Can't think of anything in the drivetrain that might cause that other than maybe a lean fuel condition due to fuel boiling, etc. However, you shouldn't feel a rough engine in the steering wheel.
Maybe a tire tread is delaminating. It takes time to heat up and swell a bubble. I had that on my '82 Chevy S-10 w/ crappy Uniroyal tires from the factory. All 4 tires had the tread come off in chunks before 20K miles. That caused severe vibration on the highway.
Maybe a tire tread is delaminating. It takes time to heat up and swell a bubble. I had that on my '82 Chevy S-10 w/ crappy Uniroyal tires from the factory. All 4 tires had the tread come off in chunks before 20K miles. That caused severe vibration on the highway.
Sounds crazy, but have you checked your motor mounts?
That sounds serious, and if you get a vibration at 3,000 rpm while in park, that makes me wonder... and it still doesn't rule out the torque converter if I understand it correctly.
I'd find and fix the problem before I took it back on the road - that sounds scary.
That sounds serious, and if you get a vibration at 3,000 rpm while in park, that makes me wonder... and it still doesn't rule out the torque converter if I understand it correctly.
I'd find and fix the problem before I took it back on the road - that sounds scary.
Pristine '73
Well-Known Member
Internaly ballanced engine with an externaly ballanced harmonic ballancer......... That is ar least part of your problem, confirmed by the fact that it vibrates when free revving in park.
SRT_DSTRHOLC
Well-Known Member
they would have or should have said the balancer was incorrect when he took it in to have it balanced
1968FormulaS340
Well-Known Member
He says in post #7 that he reused the old one.
swinger340
Well-Known Member
Had similar problem with a 360. Mine ended up being that the harmonic balancer counter weight had spun in the rubber. Changed balancer and then was fine. Mine became more and more noticable the higher the rpms got. If this was internaly balanced and your running an external balancer that is a definate no no.
SRT_DSTRHOLC
Well-Known Member
oh now i see that found the problem.
when i took the engine to the machine shop when i got it. it was horribly out of ballance so the guy used the b&m flex plate and found out there was a 318 balancer and told me that he could balance every thing with what i had and it ended up being a pound out of weight over all so he added weight to different places and took weight out of a couple of places on the balancer but the car was driving perfectly fine for the first few months i have just now started having the weird vibrations
pettybludart
Well-Known Member
Yes,check your harmonic balancer for seperation.You,ll beable to see the rubber liner sticking out in areas if it,s seperating.Let us know what you find.
after replacing all of the suspension parts om my car and re adjusting them several times i have finally found my vibration problem!
it was the rear end. it is a 8 1/4 out of a 1973 dart and someone told me i should check the axles and bearings on it and sure enough i took it apart yesterday an found that one of the axles is egg shaped with a 16th inch deep grove in it where the bearing rides. so now i am putting a 8 3/4 housing out of a challenger and a pumpkin with 323 suregrip gears out of a original AAR cuda.
it was the rear end. it is a 8 1/4 out of a 1973 dart and someone told me i should check the axles and bearings on it and sure enough i took it apart yesterday an found that one of the axles is egg shaped with a 16th inch deep grove in it where the bearing rides. so now i am putting a 8 3/4 housing out of a challenger and a pumpkin with 323 suregrip gears out of a original AAR cuda.
cudamark
Well-Known Member
I would just get a new axle shaft for the 8 1/4 before I did anything drastic. You'll want to repair that rear end anyway if you plan on selling it. The E-body rear is going to be way too wide for an A-body without narrowing it. I think I would sell it and use the money towards a correct width rear for the car if you can't live with the 8 1/4.
actually i wanted to go with a 8 3/4 originally and the new rear is under the car right now and it fits perfect and the wheels dont stick out past the rear fender wells and i was planning on fixing the rear before i sold it but i dont like keeping parts in my car that have had problems. i dont really like the original width of the a-body rears since the front wheel base is wider then the rear. the e-body rear gives it a better stance. it also made it so i could put newer charger rims on it or something similar. there is also alot more room for bigger tires in the future. ill try to put some pics on here after its all done.
pauly v.100
Well-Known Member
How could bad axles/bearings cause a vibration when in park!!
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