Loud Clunk in SPF

[cdog]

Hi all.

I have a noisy clunk in my SPF somewhere. It occurs when stopping for a stop sign. If you hit the brakes hard, you hear something hit underneath. Let up, and it hits the other way. Hit em again, and it hits again.

When you fully stop, and let up the clutch, it hits right at the first forward movement. By "hit", I mean something whacks the frame...

It appear to be something shifting during weight transfer during accel/decer and is not torque/engine speed/road speed related.

I checked the tranny/rear end bolts and brackets, all seem ok. It may not be in the driveline, but seems to be coming from underneath....

Any ideas?

C

[mikiec]

Check your front upper control arm bushings?

Mike

[cdog]

I didn't really check anything in the front, as you can feel the clunk coming from directly under the seats... I think its in the back for sure..

[mikiec]

Something is very loose. Generally when stopping or starting I have seen loose control arms or shot bushings. You have IRS check those bushings as well.

Did you physically try to move the tranny up and down and back and forth? The same with the engine?

Double check all suspension mounts, ball joints etc..If all this is tight and to torque specs then....I'm out of ideas.

Mike

[John 550]

sounds like a u-joint

[Mr.Fixit]

SPF's can have the right axle's inner CV hit the framerail where it passes through. This is usually indicative of a torn right front diff mount, on early SPF's before they reinforced the forward diff mounts

[Rodney]

Check your sway bar bushings as well! The rubber bushings dry out and crack along the mold seams. Maybe yours fell out all together? Just a thought.

[cdog]

Guys, I still haven't resolved this. It still feels like a bowling ball is loose in the trunk.

It is a loud clunk (like someone hitting the frame with a hammer) that occurs just under braking (and when you stop braking). It also occurs if you stop fully (the forward clunk) and then when you go again (clunking back the other way) m a complete stop. It is like something is transferring weight forward (clunk) and then back when I leave the stop sign (clunk).

The car does not clunk under acceleration or deceleration with the throttle.

I checked everything underneath. Nothing is rubbing, all bolts are tight. I didn't check the driveshaft to rear end connection, not even sure what to check there. There is some play in the CV joints and the rear end, but it doesn't seem excessive. A few thousanths in those components is quite a bit at the wheel...

[thudmaster]

Mine was my damn lead hammer in trunk.


Ed

[Cracker]

Did you check the diff mounts like Mr. Fixit suggested? It should not be difficult to duplicate. Have a friend assist and lay beside/behind the car and move the car. If it's as pronounced as you claim it to be it should be relatively obvious. Best wishes.

[rob frink]

Cdog, not all but many SPF's have an inherent clunk in the drivetrain. My car has it and it is most noticable when I'm slowly rolling along in 1st or 2nd gear at idle. Not accelerating or braking...just rolling. As the car lurches back and forth from the cam lope...I can hear and feel some clunking from the rear-end. I've searched and searched for the source but have never been able to find it. I think it is just tolerance stack-up in the drive train. It seems to be normal and I've learned to tolerate it.

On the other hand, as cracker said, as severe as your's sound...it should be obvious when you get under the car.

Double check the tightness of all of the drivetrain fasteners. If you have the driveshaft emergency brake, check the driveshaft bolts. In some cases, with this arrangment, a few SPF'ers have reported that the bolts have loosened over time. If your car (I believe) is in the 1900-2000 range...also check the torque on the rear axle nuts. In some cases, these nuts worked loose.

Good luck and keep us posted. Hopefully your experience will help me find out where my clunk is coming from...but in the meantime, I've learned to drive around it and I really don't have any complaints.

-Rob

[REDSC400]

Can you replicate this in your driveway or parking lot?
If so, have a friend stand by, accelerate and then turn off the engine as it is hard to hear over the engine. With the engine off you may be able to pinpoint the origin better.

Has something come loose inside the gas tank?

Take every last item out of the car, trunk and such. Check all wells and behind the seats.

Do you feel the clunk, hear the clunk or both?

I had a clunk in my ERA which I swore was from the front end. Come to find out a pair of pliers was in the rear trunk well, along the side and on a bump it would clunk. Found it one day when I did "Spring Cleaning"... go figger...

[Slojo]

Check the battery. It's in the trunk, driver's side right? See if it is loosely fit in it's 'box'. I didn't read this entire string, but have you had the car dyn'oed, does it make that sound on the machine?

Good luck.

[JBCOBRA]

I have a clunk/metalic sound in the left rear #2218...........I think thats my number LOL, anyway my buddy has it too. His car has a Ford rear, mine is a Dana. We have taken everything apart and checked/retorqued everything. Nothing obviously wrong. Sounds like it is in the cv but can't prove it.
The sound is most pronounced going gently from reverse to first or visa versa.
Still scratching my head on this one.
JB

[Jerry Clayton]

Chuck

Give us a call after about 10"30am----I can probably fix your clunk

Jerry Clayton
630-365-6737