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Aren't GM cars designed for tire-chain clearance? Everything but Corvette and maybe some other "specialty" vehicles, anyway. I was screwed by California DOT on I-80 at Truckee, CA, years ago. The prick wouldn't allow me back onto the highway without tire chains. Had to buy tire chains at a local store. It's a damned racket--the road was wet with melting snow but there wasn't any actual snow or ice. It's just a way to fleece the traveler. My vehicle had "Mud/Snow" rated tires on all four corners, and the town I lived in had more snow than the ZERO snow that was on I-80. Anyway, my '92 Lumina Euro 3.4 clanked and rattled about half-way down to Sacramento, with the chains flailing. I can't imagine another half-inch of tire would take up more room than tire chains. t

Apologies for the wall-o-text, but I got started writing and didn't stop for over an hour and a half. There's no TL;DR version. I've been the unwitting victim of over a decade of experiences with the 284, and I would liken it to having an autistic child - moments of brilliance and joy tempered by fear of what's coming next. So here we go. Something I've discovered about high-mileage 284's. If you put it together and you get a weird side-to-side shimmy under acceleration, and at 154k I can almost guarantee you will, it is most likely because of worn output shaft bearings. I'm currently on my 3rd 284 in my car and every one of them did it. Initially I blamed the axles as anyone would, but even with brand-new axles it still did it. What happens is the output shaft bearings in the differential wear beyond tolerance, and allow excessive movement in the output shafts. This manifests as an acceleration shimmy and an output shaft seal leak, usually on the driver's side. I don't know what the solution to this is. I bought up a bunch of output shaft seals a few years ago on closeout at RockAuto and had an idea to fill the empty space in the back of it with an epoxy, like JB Weld, that it might strengthen them enough to smooth it out. But I haven't tried it yet. If anyone else has experienced this and/or found a solution to it I'd love to hear it. My other idea was to flamespray the stub axle's bearing surface to enlarge it. The most important thing to know about 284's is that they are made of unobtanium. GM did not allow anybody at the dealership service depts to disassemble them for repair, they were R&R only. Taking one apart isn't that complicated, but you do have to have some highly specialized (and likely non-existent in 2018) tools to put one back together, including of all things an oven. The part you remove to get at the detents in the bellhousing supposedly has to be destroyed in order to remove it, and replaced during rebuild. So, there's that. They were built at a Getrag production line in SC, which is where they were supposed to be sent for repair, and in 2003 all the remaining service parts they had were auctioned off on eBay. In 2007 I spoke to the last guy who knew anything about them at the SC factory and he couldn't believe there were still any on the road. At the time, technically mine wasn't. I don't know what kind of magic the wizards at Getrag used to come up with the 284, but it was an engineering marvel in its day that was largely overlooked. However, its two main weak points are those 3rd-gear syncros and the output shaft bearings, plus the fact that you weren't supposed to take one apart outside the SC factory in the 90's. Point is, don't buy one of these expecting to be able to rebuild it like any other transaxle. The one advantage a 282 has over a 284 is rebuildability. Maybe in 2018 with 3D printers that can make titanium parts out of electronic 0s and 1s we can make some of the pieces necessary to do it, but I don't know of anyone who has attempted it yet. Me, I've got 1 good spare in case I ever have problems with the one I've got now. One other thing I didn't see mentioned, is check its mount. They don't make replacements anymore and you're going to need it. It's like a foot on the bottom of the case. Hopefully it wasn't damaged in the process of removing the 284 from the subframe. They usually split in half. Make sure you can't pull the top half away from the bottom half.