If I install an aftermarket muffler, will it void my powertrain warranty?

A buddy recently did this to his new Jeep and presto.... warranty void. Oops!

I could understand an entire aftermarket exhaust system voiding a warranty, but just the cans? Anyone know how LR feel about this?

 

It's against the law for a mfg to void a warranty for installing aftermarket parts, provided the parts are OE equivalent.

 

Be it a factory warranty or aftermarket, if you install a non factory part which then leads to a failure, that part of the vehicle is no longer covered by a warranty while the rest of the vehicle is still covered.

 

The manufacturer can deny warranty on the specific part (which makes sense since it isn't their part), but as far as consequential damage to, for instance, the engine, they must prove the aftermarket part caused the damage. That's been the case since 1975 when the Magnuson-Moss Warranty Act became law.
And they can't just see the part and say, "Oh, your warranty is void". Well, of course they can saw whatever they want, but that doesn't make it so. They have to prove it caused the damage.
Of course, many people just take them at their word and go away (or give them lots of money to fix it), which is certainly what the dealer hopes.