Piston Slap: Giving a Pacifica the (Drive) Shaft?

Stefan writes:

Sajeev,

We just had the drive shaft replaced on my wife’s 2008 Chrysler Pacifica AWD (no, not the new minivan — the old crossover). It’s been a good and reliable car in spite of its less than sterling reputation, and we have a little over 100,000 miles on it. The 4.0-liter engine with the six-speed transaxle delivers plenty of pickup and all was well until the (center) driveshaft went bad and we had it replaced by our trusty independent auto repair shop.

The problem lies with the new drive shaft, which shudders at low speed when you accelerate and moans between 40-50 mph. The shop can’t figure out what it can be and what to do.

So, what’s your take on the situation? Can you and the B&B provide some insight in this matter? The vehicle is well cared for otherwise and in excellent condition. I am inclined to keep on driving, since you don’t get much for them as a trade-in — but maybe it’s time to think of a replacement? What says you?

Sajeev answers:

Not all replacement parts are created equal. And considering that your drive shaft is significantly more complex than your stereotypical American car drive shaft, there seems to be several areas where a slight intolerance/imbalance could cause your problem.

I wonder if the giubo at the end wasn’t torqued down correctly. Or maybe one of those universal joints are out of spec. Or maybe a drive shaft balancing weight decided to leave the party? I’m gonna remain optimistic and suggest it only needs the latter addressed — maybe an extra weight to get back on balance?

Or just get your shop to replace the whole thing: whatever it may be, I think you’ll have plenty of good years left with this Pacifica if it’s done this well for you so far. It’s a keeper.

What say you, Best and Brightest?

[Images: Cargurus.com, moparpartswebstore.com]

Send your queries to sajeev@thetruthaboutcars.com. Spare no details and ask for a speedy resolution if you’re in a hurry…but be realistic, and use your make/model specific forums instead of TTAC for more timely advice.