Jump to content

Avant shudder.


A83
 Share

Recommended Posts

Now my 83 Avanti shudders when driving.  No problem when I rev the engine in neutral or going in reverse.  Only when in gear. It is like I am driving over railroad ties.  Sometimes real bad sometimes not as severe but dreadfully noticeable.

Any ideas? 

 

Thanks A83

Link to comment
Share on other sites

Can you narrow it down as to coming from the engine, transmission, suspension or elsewhere?  From the very little information given, I would guess a failing transmission.    

Link to comment
Share on other sites

Thank you both - near as I can tell when I put it in neutral and rev the engine while driving the car, it does not happen.  Seems to be when I have it in gear (automatic transmission) starts at about 15 mph.  Not sensing anything from the suspension.  Wondering if drive shaft might also be a possibility in addition to the torque converter.  I have been having problems going through several new brake boosters and each one keeps hissing  as the current one is / also new brake lines out in recently.  Could the brakes be engaging due to the brake booster?  

 

 

 

Link to comment
Share on other sites

No the brakes are not engaging.  With the bad booster, you would just lose boost and perhaps some vacuum in the engine (that could make it run strange).  There isn't anything to apply the brakes, like with an ABS system.  I would say no to the driveshaft.  It could be the transmission itself, as well as the torque converter.    

Link to comment
Share on other sites

My '82 Avanti-II shuddered  like I was driving over railroad ties, especially noticeable under acceleration.  I suspected the U-joints and had them replaced. That didn't cure the problem.  When the starter went bad, the mechanic who removed the old starter found that the plastic cover under the bellhousing was pinched by the starter and rubbing against the teeth on the ring gear.  A Dremel tool relieved the interference on the plastic cover and that fixed the shudder.   

I  experienced a similar "driving over railroad ties" sensation driving my Wagonaire home from a tire shop where I had just had a new set of tires installed.  Popping the hubcap on the drivers side front wheel I discovered the lug nuts were on finger tight, just started but never tightened down.  It ruined not only the studs, but wallowed out the bolt holes on the wheel. 

Link to comment
Share on other sites

I found some loose lug nuts and tightened them up.  Took for a test drive and the railroad tie feeling diminished but not gone.  When I came back from the test drive, one lug on rear driver side wheel was loose and retightened.  Now it seems to vibrate at around 20 miles an hour when I accelerate but shudders noticeably when the car starts to decelerate at around 20 miles an hour.  Did not highway test it yet.

Any more thoughts?

Appreciate any help.

 

A83

Link to comment
Share on other sites

Looks like the shudder problem was a combination of bad plugs and a worn control arm bushing.  Engine runs fine but detect a shimmy in the front end when  driving which gets worse when I decelerate  especially in the low gears (auto trans).  Does this week plausible? 

Link to comment
Share on other sites

2 hours ago, A83 said:

Looks like the shudder problem was a combination of bad plugs and a worn control arm bushing.  Engine runs fine but detect a shimmy in the front end when  driving which gets worse when I decelerate  especially in the low gears (auto trans).  Does this week plausible? 

These items could cause problems, but not what I would describe as a "shudder".  A vacuum leak due to a defective brake booster can also cause an uneven running engine, but I didn't mention it because that also would not be a "shudder". 

Link to comment
Share on other sites

Maybe I am using the wrong terminology but am using the term shudder to describe the feeling of driving over railroad ties.  That feeling is gone now and I felt it pretty much under the seat/ transmission area.  But still do get a vibration when driving and more when decelarating.  So will l have the control arm checked out next.  Not sure of anything until this is all over so also made a list of all your recommendations for another hot rod shop I am taking it to this week and I thank you all for your help. 

Link to comment
Share on other sites

  • 2 weeks later...

Update - control arm bushings replaced and the U joints on the drive shaft replaced by a mechanic - car running nice - thank you to everyone for your  help and advice. Always appreciated.

 

A83

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share

×
×
  • Create New...