Piston Slap: Justy-fied service for Subaru’s CVT?

Robin writes:

My 1994 Nissan Hardbody, while I love it dearly, has been set aside as a daily driver and reclassified as a project. In its place is a 2014 Impreza, purchased as a CPO from a Subaru dealership. Perhaps I should have gone with a Corolla, but I’ve had this secret thing for AWD and boxer engines for quite a while!

Here’s the issue: regarding scheduled maintenance, Subaru of America says to leave that CVT gearbox alone. I’ll void the warranty if it’s cracked open before the 100,000 mile warranty. At my last scheduled maintenance the dealer wanted to do a flush/fill, but I deferred due to the warranty info. I was suspicious of them trying to up sell service despite the warranty statement.

Yet, apparently, Subaru of Canada and Subaru of Japan both dictate regular flush and fills. Knowing this, I’m leaning toward a service, but I need more data to base a decision upon.

Sajeev answers:

It’s a well-known fact that car dealerships make a huge chunk of revenue via customer pay upselling. Which is fair, if they prove the work is needed, and if their prices are in line with others in the market. Your Impreza’s fluid must be smokey colored/foul smelling, or the gearbox must be leaking from a bad gasket or a cracked pan (i.e. off road excursion). Such proof is needed to be justy-fied in doing a CVT fluid service. So go back and see if they can back up their claim.

That said, the gearbox needs servicing around 100–120K miles because lifetime fluids are a joke. The USA is a tough place to sell cars (not trucks), so lowering maintenance costs for shorter term buyers/leasees is an important marketing tool. But don’t take my word for it, learn why from the baguette crushers over at ZF Group:

So let’s indulge in a hypothetical: the previous owner towed a big ‘ol boat with your Impreza, your “lifetime” fluid is charbroiled, therefore a fluid service during the warranty period is logical. Do the work at the dealership, after insisting the Fixed Ops manager (i.e. the person in charge of service/parts departments) commits that they/Subaru will repair a CVT failure at no cost to you, if the new fluid caused the problem during the warranty period.

The odds of this work (performed by a Subaru technician using Subaru parts) actually killing a gearbox is nearly impossible, and it is unlikely anyone would void a warranty for this reason. I consulted a friend who is a Ford Service Zone Manager, and he added, “You can never be penalized for too much maintenance.”

Let’s end the hypothetical: if the dealer resists your request for the aforementioned commitment, replace the fluid after the warranty expires (or perhaps after 100–120K miles) via any reputable mechanic using the correct fluid.