Thunk sound from rear under load.

[accidentprone86]

So I have a kinda weird problem. Every time I go past 10% throttle I hear a loud thunk come from the rear of the car. At first I thought it was the pinion gear on the ring gear but then I tested it out a little more. Like I said it is only at about 10% throttle, I can be accelerating "so the pinion and ring are in contact and under load" but then when I give a little more gas it will make the sound. It doest not do it when decelerating.
What else could this be?? I know it isn’t the ring and pinion.



Thanks:SNSign:

 

[1991vert]

is it taking off quickly? the pinion snubber could be shot and your axle pumpkin is hitting your car. happened to me all the time until i did my springs and got a new snubber

 

[Thenemesis]

sounds like your trans isnt mounted down good.. my 86 did it for a long while.. when i put my X pipe on it, low and behold the bolts werent tight and the mount was ate up and worthless.. just one thing that could be wrong

 

[mustang-a-holic]

Torque boxes.
U-joints

 

[accidentprone86]

It sounds almost like a snapping if I take off going up a hill. Also if I let off of the gas in first and second and let it cruse at idle it we jerk back and forth each time making the thunking sound.

 

[iapexl8r]

sounds alot like upper control arm mounts are shot, usually the sheetmetal tears then when you slightly accelerate or sometimes decelerate it pops or pings just another thing for you to check out. Chris

 

[sgarlic]

Driveshaft clunk I bet.

 

[dannydoo]

tranny mount,u joint,or any of above,all are possible.


.jack up the rear..both sides by the lowr cntr arms
make sure its supported really good..and carefully jerk the tire back and forth by hand...if u cant see what is loose....then get more drastic.
maybe have some one looking under it,while your backing up on a set of ramps,or going down them..
just ideas....u gotta get under there and see whats up.
we can only give you ideas..the rest is up to you.
whatever it is....im betting its a simple fix!!!so get to it!

 

[Aliate X]

I am getting this same exact sound, sorry to dig a thread up.

But its coming from the left rear of the car. The upper and lowers are only about 5 months old with new bushings and stuff. I recently did a TKO swap using the stock driveshaft.