Piston Slap: Dodging Trouble Again?

Tom in North Carolina asks:

Thanks for taking on the synthetic vs. standard oil change question on my 2005 Dodge Durango a few months ago. Now for a new challenge: the same Durango, 78,000 miles, 5.7 Hemi with 5 speed automatic (trailer tow package and transmission cooler). It’s a highway cruiser, bought it to tow a boat with trailer. Except I have a boat slip now so there’s very little towing needed.

The dilemma: the manual says nothing about changing the transmission fluid if the vehicle is not used in severe service. Since I am skeptical of lifetime fluids, I think the fluid needs to be changed but don’t have any idea when to do so (FWIW: it is still a nice shade of red on the dipstick).

My options:

1.The local Dodge dealer recommends that the transmission fluid be changed weekly (well, almost), with both internal transmission filters changed, at $250 per service. Since the transmission is a closed system, I can’t really see where contaminants could get into the system that would require that the filters be changed, but being wrong could prove to be very expensive.

2. The local Tire Kingdom will do a fluid exchange/flush for $110. I used to do this every 75,000 miles with an Isuzu trooper that had a sealed transmission and never had any problems when I sold it at almost 200,000 miles. Is flushing out all of the old fluid and replacing it adequate (as long as the correct fluid is used), and more than the service manual requires?

3. Do nothing. The whole power train is overkill/overspec’d for highway trips and will probably last forever with engine oil changes and the occasional set of 16 (!) spark plugs.

I want keep the vehicle for another few years, and maintain it appropriately. It is not a Bugatti, nor is it a clunker. I am not from the “change the oil every 3000 miles because that’s what daddy did” school, nor the run it till it breaks crew. This vehicle is a heavy duty appliance, and I want to maintain it as such.

Sajeev replies:

There is no wrong answer, especially if Chrysler (and their Lifetime Warranty) stays around as long as your interest in this vehicle remains. Then again, don’t hold your breath on that.

And transmission filter(s) have purpose, needing replacement at some regular interval. But the conventional “drop the pan” service is the only way to do it. Which, if your torque converter lacks a drain plug, cannot remove old fluid as well as the “flushing machines” at local oil change places. Confused yet?

I’ll simplify: find a place with a transmission flushing machine plus a service bay to do a filter change. Ask them for a package deal on both services, unless you do have a drain plug on your torque converter. (If so, do a conventional service and hope the mechanic drains the torque converter.) And do this in the next 20,000 miles or so. Repeat again in another 50,000-100,000 miles, depending on condition of the tranny fluid as the years go by.

There’s no rush: you’re on top of things. Your game plan for the coming years determines just how bulletproof this Durango shall be in the future. And, short of doing neutral drops at stoplights, you can’t go wrong with any transmission regiment you have in mind.

(Send your queries to mehta@ttac.com)