I haven't been posting here in a while; since last summer when I did brakes, shocks, and a few mods, and was very satisfied with the results. Happy with the HHR, I started building a trailer to pull with it. Now my attention has to shift back to the Panel. Just recently, 12000 miles after the running gear fixes, I've started experiencing a harsh clunk under the car, at very low speeds 10-20mph on moderately rough surfaces. More pronounced as the temperature drops, but seems to go away at highway speeds, no matter what the surface is like. PLUS a shudder in the steering at 60-65mph, and on braking starting at 30 down to 15 mph. These problems don't seem to be connected, as I don't detect them at the same time. I've rotated tires twice, run different pressures in them, and checked all bushings and linkages for looseness and found nothing. I also ran a flat edge over the rotors in several places, also checks good (braking at 75-30 is smooth, no vibration!). I've also had my mechanic friends drive it, and they are puzzled also. The disconnect between the two problems leaves me wondering if I should continue to drive it until the root cause becomes painfully apparent. The only other thing I can add, is that the front struts handle all surfaces pretty good, and have no leaks; and that all tires are in good shape, with 40% tread left, despite being Affinities @ 69000 miles. I'm inexperienced on FWD cars; if it was a RWD I would've figured it out by now. MORE INFO: there is also a low speed rattle under the dash, but not always. And my mech expert friend said the problems are not similar to his experience, having repaired clunks and brakes on his 2 personal HHRs (including shocks, struts, pads, rotors, bushings etc...). Help, I love driving this Panel .

 

My first thought is a CV joint is starting to fail on you, which would explain the juddering and clunking. What can happen is that one of the ball bearings can get worn or actually fracture and cause the joint to bind up as it rotates. Have you checked the CV boots for tears and leakage?

This could also be a failure of an inner CV joint, which is actually a misnomer since the inner joints are properly called "tripod joints". When these fail you'll get a shuddering and clunking, sometimes they'll even "clang" like a bad U-Joint on a rear drive vehicle.

 

843de- I found nothing loose or torn or leaking anywhere underneath. My prior experiences with CV joints were that I could easily detect where the problem was ('85 Chrysler Lebaron Turbo, '88 Pontiac Fiero, '92 Olds Achieva SC). When the CV's on those started going bad, there was noise and a discernable steering problem on turns (on the FWD cars). My panel makes no noise on turns, no noise in a straight line, and when I have the wheels off the ground, no excessive play in the axles. Another thought here: in addition to the info I added to my prior post, I also have noticed that my Panel has a lot of weight transfer on acceleration now. Despite new shocks on back (12000 mile old KYB's), and rubber wound rear coils, the rear squats and front rises like my doorslammer, but I can't spot why.

 

You might have a bad/broken engine mount, that would create some odd noises and handling quirks.

 

That would explain the weight transfer alright; that thought never occurred to me. How many mounts are there? I've looked at one on each side, am not sure of all positions though (I've only replaced two dogbones on other FWD's before).

 

There are 3 mounts, and by the sounds of your problem it may be one of the mounts on the transmission that has failed. Here's a thread with some info and photos on the mounts and their locations.

https://www.chevyhhr.net/forums/problems-service-repairs-42/my-hhr-growling-not-good-kind-38502/

 

Control arm bushings?

 

Not out of the realm of possibility George, but the rearward and unexpected weight transfer he's describing almost screams bad mount/mounts. If the drivetrain is moving about and dropping/twisting out of line, you'll get a shudder in the driveline and assorted clunks and thuds.

 

843de-Thanks, I didn't check the rear (my oil drain pan, full of hot oil, was underneath that area). I also must've missed that page on my zipped folders of HHR info. I'll check it the first chance I get... off work during daylight, no wet ground (garage is full).... Even if that rear mount is not loose or broken, I will want to firm it up anyhow, now that I know it can be a problem, even on a 4 banger. I've been using polyurethane replacements on my trucks' tranny mounts for years, and steel on my BBC/Glide w/brake as well. If that doesn't fix the problem(s), at least it will head off others. Worst Case Scenario: I may have to test to destruction, to definitely determine all defects. I can't throw money at the HHR right now, I'm throwing too much at my trailer project right now, and have to get it finished (and moved) asap.

 

working on it-

With engine running, hood open & an assistant. Hold brake firmly & put it in gear, (& might need to give a slight bit of gas ) if you have a broke mount, engine lifting will show you which one..

PS: Whoever is watching the engine should stand beside car, & NOT in front.. LOL