In today's climate it is often difficult to apply common sense to the law, so in this case use common sense as a guide line only. One thing in your immediate favor (actually in the long run it works against us all, however) is the fact that courts, juries and the law generally are ANTI big business and pro almost anything else.
Common Sense: Any vehicle alteration NOT done by the dealer or an AUTHORIZED representative of the manufacturer that COULD have an impact on the warranty problem in question is likely to be DISALLOWED by the manufacturer or dealer or both. Something as obvious as oversize tires combined with an automatic locker in a D35 axle would give the mfg a good cause for disallowing the warranty claim on a broken axle. Doesn't mean they will, just means they would have logical and reasonable and probably legal grounds for their position, but what if your family buys 4 new vehs a year from this particular dealer???? Or what if you drive into the shop at 30 mph, hit the brakes, slide halfway accross the shop floor, jump out and start screaming while you begin to paint lemon in big yellow letters on your new red TJ? Another example, and this one really happened was when a friend of mine broke a D35 axle on a TJ equipped with a locker and 35 inch tires, and according to him, really was keeping the rpms just below red line when the axle broke. The guy called a Jeep dealer who looked up his rather large buying record from Chrysler. The Jeep dealer gave him a new axle accross the counter so that he could take it back to the trail and install it. As far as I know the dealer never even saw the broken axle shaft. Know he had nothing to do with its installation.
Going back to common sense. Be prepared to pay for repairs on items that could have been affected by your non authorized modification, and be prepared to go to the wall with the dealer if he wants to disallow a warranty problem that is completely disassociated from your modification. Also developing a good rapport with a single dealer COULD (not guaranteed) work in your favor if a questionable problem arises.
FYI, the "Big Foot" edition of the Wrangler is generally, if not always installed outside the dealership, but with their authorization, and it is sold as new from the dealers lot. It involves a body lift. Could be wrong, but I do not think it involves any suspension lift at all. It also has 33x12.5s, I think. Might be a little shorter tires, 31s or 32s, but I think they are 33s, and I know they are 12.5s. All this stuff has the factory or dealer warranty.
Hope this helps.
Doug '97 TJ
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