Vibrations and thumping sound

[Dreadl0ck]

First question:
Driving home last night I noticed that the car started vibrating from underneath - thought I was driving over some bad pavement or those pesky white thick lines they love to paint on the roads here in sweden to make you slow down. Nothing. Next thought was that I had something bad going on with one of the tires but I noticed the vibrations go away when car was neither accelerating nor slowing down.

I then thought bad U-joint, or something bad with the driveshaft, but weird is that the frequency of the sound goes down when driving slower and picks up in frequency when going faster.

Any ideas? going to lift the car later tonight and check for play in the driveshaft or if I can see any apparent things with the joints.

Second question:
Car will not hold in Park. When I put it in park it can roll - just like another neutral so I was thinking parking pawl. But it might be a linkage thing as well because the car won't start in park - only in neutral and it's hard to move the shifter down to 1 - feels like the linkage is off half a click. Any ideas?

Third question:
My rear is always locked. If I raise the car and turn one wheel, the other turns the opposite direction which it's supposed to do (right?) but as soon as the car is on the ground - its always locked which really makes the turn radius bad and is crappy when backing up. Are there any adjustments one can do or do I need to tear down the diff and take it from there?

Other than that - I never look back at my SRT8 any more...Love the car. Big cheers from Sweden

 

[747mopar]

I'm assuming it's a 727 auto with an open differential? Sounds like you know the probable cause of the tranny issues. What I like to do when adjusting the linkage is unhook it at the tranny then manually put the tranny in park while having the shifter in park and see if it's lined up. I adjust until it drops right in then do the same for drive, keep playing with it until you get it dialed in. Also manually putting the tranny in park will confirm if it's a linkage adjustment issue.

As far as the diff goes if it's spins opposite while jacked up it should be fine? Does it only leave one patch while lighting them up?

Sounds like you've got a driveshaft or driveline issue on the vibration. The thumping makes think you might want to look at motor and tranny mounts? Also a broken leave could let the axle wrap causing a bad angle and possibly be letting the snubber hit the floor (the thumping)? Unfortunately vibrations can be several things, check mounts, u joints, leaves, tranny slip yoke play, tires, etc. Good luck

 

[747mopar]

Beautiful ride by the way!

 

[Dreadl0ck]

Sorry - I got the things confused - Of course the wheel spins the same when when raised - so it's a posi-rear end (i'm at the hospital with my daughter killing of time when she's sleeping lol). And yes, I leave two marks when lighting them up.

it's not that loud thumping that one would expect from snubber hitting the floor, but yea - it's hard to describe what a sound sounds like

I just wanted to check that I was going the right direction

Thanks for the kind words on the car! Appreciate it! (Only other car I've seen with the same color is the one classic car industries have on their main page lol)

 

[drobertson]

It's always possible that a counterweight on the driveshaft could come off... I had that happen on my truck once and it spooked me pretty good for a while until I figured it out.

 

[72Fourspeed]

If you think the snubber contact with the floor is bad, you ought to hear the noise when the P.O. has removed the snubber.

 

[Garys1969RR]

My 65 Belvedere did that too. Vibration from underneath increased in frequency with increase in speed. Seemed like it was worse under acceleration. Then it started leaking tranny fluid. Alot. Looked under there, and the tailshaft housing had broken in two, right behind the rear tranny mount. I've never seen that happen before. I had a spare rear trans shaft housing, so I put it on and that fixed it.

 

[747mopar]

Sorry to hear, hope the daughter is doing fine.

 

[Dreadl0ck]

Alright - Story time

So I checked the lug nuts before heading out to chase some ricers last saturday (I was successful thank you very much) and the night turned into a tire burning frenzy after which the problem above problem. When I came home I just backed her into the garage to "take a look at it some other day". It was pitch black out so I never really did any checking really.

Skip forward to today when I after cleaning out a backed up sewer pipe, drove the kids to three different activities, changed oil on the lawn mower and replaced some outdoor light bulbs, finally had time to take a look at the car. WTF?? Two lug nuts missing??? And where the HELL ARE THE WHEEL STUDS?? I went about to remove the tire when two more nuts just fell of - they were stuck to the rim by some gravel and rubber and WHERE ARE THE WHEEL STUDS???

So my left tire was hanging on to ONE stud. The other four had snapped right off at the break disc. Removed the caliper to have some room to work. Enter: WD-40 and blow torch. Carefully heating the hub so I didn't warp anything and after some precision blows with a hammer I got them out.

Guess I need to check the other side as well...

What you you guys think? Will a wheel that's only held by one stud cause vibrations? ;) ;) ;)

 

[Garys1969RR]

I assume it was the left front wheel hangin by a stud? You know, Chrysler used to put left hand thread studs on the left side to keep them from un screwing while your driving. Don't know if it worked, but I changed all mine to right hand thread and they don't come off. You don't think some one loosened them when you weren't looking? I can't think of any way they could loosen and come off by themselves. Maybe the studs were defective and broke off when you were doing burnouts? Are you using a line lock when you do burnouts? Let us know what you find out.

 

[Dreadl0ck]

Left rear tire, and previous owner had replaced the wheel studs to right hand threaded ones. No line lock - regular burnouts with left foot brakes.

The hypothesis I'm working with is that the lug nuts and or the wheel studs had bad threads, and by wiggling around they came unloose, creating a big inertia force when accelerating hard - snapping the studs.

 

[747mopar]

If they were ran loose for any length of time causing them to break you should notice it in the rims bolt holes, there should be sign of them hammering around. Got a picture of the wheels? A thin steel rim without much pucker for the nut and an incorrect nut that bottoms on the drum before torqing the rim down is another possibility? My guess is either they weren't tightened down all the way or pore quality studs. I'd really look the rim and nuts over and make sure they match up.

 

[747mopar]

Another possibility is the studs weren't pressed in all the way to begin with allowing them to loosen over time?

 

[Garys1969RR]

It looks as if you have real wheel disc brakes? Because you mentioned the disc, and removing the caliper to get to the studs. What type of wheels do you have on there> Mags? With the wheel off, put a wheel nut on the outside and see if it sticks out the disc side at all. That sounds like the most likely cause, as 747 said. The nut hitting the caliper before it tightens the wheel down all the way.