By on January 12, 2018

2008 Chrysler Pacifica Limited AWD, Image:

Stefan writes:


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.2007 Chrysler Pacifica Driveshaft, Image: moparpartswebstore.comI 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?


Send your queries to [email protected]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.

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20 Comments on “Piston Slap: Giving a Pacifica the (Drive) Shaft?...”

  • avatar

    Just take it back to the shop that did the work. If that vibration wasn’t there before, they will have to fix it for you.

    • 0 avatar

      If the shop installed the bad part, they need to stand behind their work. At the end of the day, unless the OP requested the aftermarket parts against the shops better recommendations, it’s on them. I don’t even understand the discussion here. Why are people suggesting cheap fixes? Take it back to the shop. They need to make it right, period.

  • avatar

    The shaft is obviously out of balance. There are several things that can cause it, but there are a few fixes. Have the mech remove it completely and spin test it or replace it all together. Maybe the rest of the shaft was damaged when the old one went out or came out. Did they replace all of the U-joints? If so, did they use sealed units or greaseable units? If they used greaseable units, did they grease them after they were installed?

    Do not continue to drive the car since it will cause more damage and may fall off while you are driving.

  • avatar

    Also, there are certain parts that you don’t want to cheapen out on when you replace them. This is one. Go get the OEM part if you can’t get it corrected. The extra ten bucks isn’t worth the headache.

    • 0 avatar

      The problem is with how darn pricey OE driveshafts are. Things get extra frustrating when OEMs make things like carrier bearings and u joints difficult to replace from the factory, making people either pony up $1k-$2k for an OE driveshaft, or resort to cheaper aftermarket units that oftentimes have issues like the OP. It’s not just “ten bucks” in this case, not even close.

    • 0 avatar

      I had to replace a headlamp housing on an Outback. The OEM part was $450 vs. ~$130-$150 for the rock auto special. I don’t know if it’s proportional or if it’s always a $300 difference but it damn sure isn’t $10. Hopefully the shop can figure this out but regardless of who suggested the part, if it even is aftermarket, I wouldn’t blame the guy for trying to make do.

  • avatar

    Depends on how expensive and hard to get the driveshaft is. If easy to get and cheap get another one or exchange the one you have and try it out. If it was pricey and or hard to source (subaru driveshafts tend to fall in this one) You may want to bring the shaft to a driveline specialists that can run it out on a machine and see whats wrong.

  • avatar

    Had the same issue with my Chevy Blazer years ago. The ultimate fix was replacing the entire driveshaft assembly with high-quality replacement parts. This included the U-joint, center bearing, etc. Throwing cheap parts at the problem might not fix it.

  • avatar

    Gus Wilson of the Model Garage fixed a similar problem with a couple of hose clamps:

  • avatar

    Depending on where you live, there are driveshaft shops that could either balance the driveshaft or build one. I’d take a custom built one over some generic replacement, who knows what part supplier the repair shop used. Either way, the shop needs to fix it, if they won’t or can’t, then they’re not very “trusty” are they?

  • avatar

    Shuddering at low speed is not usually a balance problem. From the drawing there are at least three sections to this drive shaft and two, maybe a third off the drawing to the left, joints. If the joints are the cross, Spicer, type they need to be correctly “clocked” (aligned along the rotational axis) or exactly this kind of vibration/shaking shuddering will happen. If the joints are the constant velocity (CV) type they may be the “reconditioned/rebuilt” ones where the ball tracks are reground by hand and larger balls fitted. This is obviously an imprecise method and often these type of “rebuilt” shafts/joints will have vibration problems.
    The cure, as others have already stated, is a new OEM complete drive shaft.
    When I was in the car biz I worked with a driveshaft shop. Whenever someone walked into their shop with a multi-piece driveshaft with parts of it in each hand (it’s shorter and easier to carry that way) they would tell them “No we can’t repair, rebuild, balance it unless you marked the sections BEFORE you took it apart. We’ll sell you a new complete driveshaft or you can go buy one at the dealer.”
    Most of these multi-piece driveshafts are splined at the junctions and there are sometimes hundreds of combinations between the parts.
    Somewhere is a machine that can balance these multi-piece shafts along with someone with the expertise to assemble it correctly.
    Maybe you can find them.
    Easier just to get a new shaft.

    • 0 avatar

      On the other hand many of the multi piece shafts have one blind spline, ie a missing groove, so that they can only be assembled in one orientation.

      Even if the spline connection is not indexed if the shaft uses standard u-joints there are only 4 ways that it could be assembled that could be close to correct and only 2 of those will follow the particular orientation of the first and last joint in the shaft to each other.

      So put it in one of those two combinations, spin it up and check the balance. Put it in the other position check it again and compare the results. Choose the one that results in proper balance or is the least out of balance and work from there.

  • avatar

    When my T100 had a shuddering drive train – happened at higher speeds – it was a bad u-joint.

  • avatar

    “which shudders at low speed when you accelerate and moans between 40-50 mph”

    s/That’s easy – just go faster than 50 mph.

  • avatar

    A lot of times the shaft is aligned by washers under the support bearings. You’re supposed to note thickness and placement when doing the deinstall. Wonder if they left those out during the re-install?

  • avatar

    +1 The shaft is not balanced.

  • avatar
    Hoon Goon

    The Driveshaft Shop recommends unbolting the shaft, rotating it 180 degrees, and reattaching it. Sometimes it works. Sometimes it doesn’t.

  • avatar

    I had this exact same problem a year ago with my 2007 Pacifica.

    Took it to four different places, finally had one place demonstrate how in my case if you held the joint and rotated it, you could find a spot where it would catch ever so slightly.

    I still haven’t fully resolved the issue and have lived with it as FWD only. The torque steer can be monstrous but then again I can count the number of times I needed AWD on one hand.

    Now, if I could just get my rear parking sensors working…

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