inner CV joint clunk. SOLVED!

[dan]

i have edited this…

2008 Pontiac grand Prix base model.
3800 Series III L-26 N/A.
91,100 miles

i have found the issue, edited the post too save posting space, it is the engine mount, see last post for more details on my findings

i am now having a difficult time finding the part, i am sure the 2004-2007 engine mounts will work, it seems all the parts stores ONLY list the engine mounts for the 5.4 LS4 V8 engine in the GXP. i am also wondering if there is a replacement procedure for this as it seems the engine mount bolts too the oil pan itself rather than the entire engine.. rather silly but it seems the 3800 series III has a more structural aluminum pan rather than the stamped steel or plastic style pans…

Topic

[Its me]

I think you probably have it nailed…

Yes, there is a chance that it is engine mounts… Check em and let us know how it goes!

-Karl

[dan]

i think ill get a chassis ear this weekend and put some connectors on different suspension components that i think will make the noise, BUT the likely hood is the engine mount is very slim, i have owned 3 W body cars 2 of which had there engine mounts deteriorated too the point peaces of rubber where coming off, the engine mounts on these cars where rotted too bits but still they had no clunk, the Buick Century had 186,000 miles on it no clunks from engine mount, the Buick Regal LS had 200,000+ before i got rid of its old mount that was rotted apart and still no clunks as a result of mount… this car only has 91,000 miles and is spring chicken…

is it safe too power break the car in reverse and forward carefully too see if i can repeat the noise since power breaking does cause the clunk?

thanks for reply 🙂

[Lorrin Barth]

It could be a brake shoe. I’ve got loose ones on the back of my car and they talk to me.

[dan]

ill defenetly check that out! didn’t think about that! specually since i did a break inspection not too long ago on this car maybe i put something out of place, the break shoe would clunk back and forth with too much play and naturally they grip onto the rotors… ill check that out.

thanks for they reply barneyb

[John Hugon]

Check and see if the right tri-pod joint moves very much in the transmission.Up-down-sideways

[dan]

thats my next step tomarrow… if there is excessive play i will be replacing the CV shaft.

[John Hugon]

Another thing to check is the axle to hub nut to see if it’s tighten to specs… My reasoning for (my posted) check(s) is; those axles on those vehicles’s are pretty tough. I guess if the car was driven hard you would have the issue you’re having…but I think a vibration on break-away also.

I’ve repaired popping noise issues on the SS Impalas’ coming from the final drive.

[Stephen Bowen]

Open the hood.

Have a helper watch from a safe distance, this can be dangerous.

Apply the parking brake and press hard on the service brakes.

Watch the engine in the compartment.

Put the car in drive first. Foot on the brake….increase the engine RPM and watch the engine.

Repeat test using reverse.

If it rocks excessively—you have a bad motor mount or transmission mount.

Just use extreme caution. I did this test once on an Olds RWD. The engine rose out of the compartment by about 4 inches.

That’s a quick and dirty test for motor mounts.

S-

(Did I mention to use extreme caution while doing this?)

[dan]

[quote=”JTF” post=101908]Another thing to check is the axle to hub nut to see if it’s tighten to specs… My reasoning for (my posted) check(s) is; those axles on those vehicles’s are pretty tough. I guess if the car was driven hard you would have the issue you’re having…but I think a vibration on break-away also.

I’ve repaired popping noise issues on the SS Impalas’ coming from the final drive.[/quote]

yes the CV shafts are pretty tough on these vehicles but i will admit i do like too hear the engine roar, i don’t flog the car but once in a while i like too be pushed into the seat and hear the engine roar… every other time i drive it, but i don’t do burn outs or launch it or anything, other than that kinda funny one day taking my ex home i hit this bump really hard and it scared the crap out of me and it was on the same side as the clunk i am hearing, a nice thud… and i was crusing pretty good at the time possibly accelerating.

the Impala SS has the 4t65EHD and later versions have a 300HP V8, those will cause big issues if you beat on those really hard!

[dan]

[quote=”Tedybear315″ post=101934]Open the hood.

Have a helper watch from a safe distance, this can be dangerous.

Apply the parking brake and press hard on the service brakes.

Watch the engine in the compartment.

Put the car in drive first. Foot on the brake….increase the engine RPM and watch the engine.

Repeat test using reverse.

If it rocks excessively—you have a bad motor mount or transmission mount.

Just use extreme caution. I did this test once on an Olds RWD. The engine rose out of the compartment by about 4 inches.

That’s a quick and dirty test for motor mounts.

S-

(Did I mention to use extreme caution while doing this?)[/quote]

engine mounts are fine i am sure but i will check more theroughly with the car on jack stands, i had a good look at the engine mount and it looks like its in good condition, buy the time these engine mounts typically go out the cars have about 150,000-200,000 miles on them and they are rotting too peaces, the engine mount on my car is still in tact, had a look at them today, going to do more diagnosis later…

thanks for the reply!

[dan]

for those of you who said check the motor mount +1

during diagnosis i checked the ball joints, wheel bearings, control arm bushings and CV shafts and everything checked out, then i checked the engine mounts!

the engine mount is SHOT, i wiggle the CV shaft and you can watch the entire engine and transmission shimmy back and forth, i was shocked because when these go bad they are usually rotted too death and sunken down but this one looked fine, didn’t show its true nature until i tried too test play in the CV shafts! video later!

[Author]

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