Help me diagnose a bad CV joint

[Klutch9]

For about the past year or so, I get a 'clunk' from the transmission area of my Sedona when I shift from park to reverse, reverse to drive, etc. Also, if I'm coasting, and give it gas, I get a clunk. Or if I'm on the throttle and I let off, I get a clunk. Revving the motor in park will not create the clunk, nor will shifting from 1st to 2nd, 3rd, etc. I can also FEEL this clunk in the footwell area. I have visually inspected all 4 motor/trans mounts for cracking, loose nuts, bolts, and everything checks out just fine; nary a weathering crack was found in the rubber. No excess movement in any of them.

Which leads me to thinking that the driver's side CV joint may be bad. Now, I know that the typical symptom for a bad CV is the clicking while turning. I do not have this issue. Other sources also suggest that the clunking I'm experiencing IS possible from a bad CV joint. The joints aren't that expensive, but they are a PITA! FWIW, I've ruled out other things moving around and making the noise, like the airbox, for example.

 

[zzyzzx]

How many miles are on the car?
What model year car?

It's often really hard to tell a bad motor mount unless you remove it to inspect. Also, CV joints can wear out, so I don't trust them at high miles either (although that would cause more of a vibration problem than a clunk).

Are you absolutely 100% sure that all the bushings are good?
What possible suspects have already been replaced?

Did you check for loose bolts on things like the sway bar and steering wheel rack?

 

[Klutch9]

Suspension end links are new, and everything else is nice and tight. It is the Sedona in my signature, with 80,000 miles, FWD. If this was an AWD or RWD car, I'd automatically assume a sloppy U-joint, because it sounds identical to one. But since this van is FWD, I only have the CV joints to look at.

 

[Nick1994]

No 10 year/100k warranty?

 

[Quest]

Did your CV boot (on the suspected joint) ever suffers from failure before the clunk?

If so, was it just a quick repack (of the original shaft) and not a reman replacement?

If you are running a reman, then start looking from that direction.

If the shaft is still original and never suffered from any kind of boot rip, then please consider the following:

(1)vehicle on the hoist: take the CV shaft out, put it on vise clamp and then inspect the outer and inner shaft for excessive bearing to journal clearances on all angles.


If this has been confirmed to be good, then suspect that your trannie differential bearing is loosy and need adjustments.

(latter costs a bit of money and a trannie shop that has sufficient experience and factory manual to properly shim the bearing back to factory spec.)


Also: don't forget to check your trannie mounts, engine mounts and suspension components (control arm bushings, ball joints, tie-rod ends, sway bar end-links, bushings, etc. for play or worn out rubber components.

Good luck.

Q.

 

[Merkava_4]

Originally Posted By: Klutch9
I have visually inspected all 4 motor/trans mounts for cracking, loose nuts, bolts, and everything checks out just fine; nary a weathering crack was found in the rubber.


I had a transmission mount that looked totally fine until I took it out. It was totally split in two, but you wouldn't know it while looking at it still installed in the car. However, if you watched it while somebody brake checked the engine in drive, you'd see it separating while the engine rolled over under engine torque. That rubber stuff can be tricky to diagnose.

 

[threeputtpar]

I concur with Merkava_4 on taking another look at the mounts. Have an assistant power brake in both R and D and watch how much the engine move around.

If is rolls front to back in a FWD car, the motor mounts are suspect and if it moves side to side then the trans mounts are worn.

Edit: I'm assuming a transverse mounted engine in the above statement.

 

[kschachn]

Originally Posted By: threeputtpar
I concur with Merkava_4 on taking another look at the mounts. Have an assistant power brake in both R and D and watch how much the engine move around.


While observing from the side of the car, not standing in front...

 

[tcp71]

upper strut mount? I've had a loose one that would cause this type of clunk. once I know where to look you could see it move on driveline torque changes.

 

[Trav]

The noise you describe sounds like an inner joint possibly, check the boot for splitting or damage then grab the half shaft near the inner CV joint and check for play in all directions.

 

[asand1]

I've had several CV joints go bad, but it was always clacking in a turn, never a knock like you have. I would suspect strut mount, control arm bushing, or motor mount.

 

[Trav]

Must be on those cv axles that only have one joint. LOL

 

[Klutch9]

I should also add that I recently had the van aligned at the dealership, who always looks for things to replace (some legitimate) and they mentioned nothing. If there was something like a loose bolt on a suspension part, a bad bushing, etc, they'd have mentioned it, especially I'd it affected alignment.

 

[Trav]

You should always check things out before tearing into it but generally when it comes to CV joints a clicking noise is the outer joint and clunking is the inner.
They are two different types of joint, failure of the outer is more common.

 

[chestand]

The classic symptom of an outer CV going bad (known as the Rzeppa joint) is clicking especially on turns. This is caused by the multiple balls developing excess clearance against the cage that contains them. This usually happens as a result of a torn boot, grease loss and then water or dirt infiltration. However, there's another joint on the transmission side called the tripod joint. It consists of a housing with three channels machined into it. Three bearings ride in these channels. I've had tripod joints go bad with exactly the clunk you're describing. When you install a reman halfshaft, you replace both joints though.

 

[Klutch9]

This makes sense... I can get a new halfshaft assembly on RockAuto for around $48 + shipping. To diagnose a bad joint, do I have to have the front wheels off the ground?

 

[Trav]

No, its better if the joint is unloaded like it is on the ground, ramps are okay.
Check for play in all directions of the inner joint. If its bad you will feel it.

 

[Klutch9]

Originally Posted By: Trav
No, its better if the joint is unloaded like it is on the ground, ramps are okay.
Check for play in all directions of the inner joint. If its bad you will feel it.


So for example, if i move the shaft and can hear a clunk coming from the inner joint, that's a telltale sign. What if I try to twist the shaft... if I get any slop from the inner joint, I also assume it's bad?

 

[Trav]

Exactly

 

[Klutch9]

Originally Posted By: Trav
Exactly


Thanks! Your insight is much appreciated. I'll get under the van within the next few days and report my findings. I'll check the other side too so I can compare both shafts.