Quadratrac

If you find one of these vehicles, and the rust situation is manageable, then it is probably worth buying. I have seen them, even in sunny Colorado, for sale in the used car lots, with plywood, plastic, or nothing at all where the floor used to be. The rear lift gate is a problem area too, as are the quarter panels. If the body is worth saving, then in my opinion the vehicle is probably worth saving.

Quadratrac used a special fluid, that you had to get from a reliable source. It used a vacuum control system, that tended to give problems even when new. I remember Consumer Reports slamming it for this. If you want to keep the Quadratrac, it would be useful to find a reliable source of information, manual, or mechanic who works on them locally. There was a low range option, that would be very useful to have for wheeling. If the vehicle has this, and the transfer case seems to work reliably, then it might be worth keeping, at least until it starts to fail. Another option is to convert to the gear-driven Dana 20, and put locking hubs on the front.

Buying one out of the want ads or a used car lot, and taking it off road the very same weekend, is not likely. Restoring one to working condition is a worthwhile goal, but I wouldn't want to have to deal with much rust.

Earle

Word in the 1970s was that the Quadratrac, a chain-drive transfer case, came from the factory with a crying towel. These two sites have a more sympathetic opinion:

Carl wrote:

The OT was an early chain-driven TC, and most came without a low range, which was an option. Because of the latter issue they are best avaoieded unless you plan on nothing more than some trips to the store in snow. The few CJs sold with the the QT also came with an offset rear differential, making it a PITA to convert to a std D300. In that case you have to swap in a differnt rear axle, etc.

In later years the Grand Cherokee & Cherokee full time xfer case included low range and has been a fairly good box.

My '77 Cherokee Chief has Quadratrac, with the gear reduction unit. At 267,000 miles, it's about to get it's third Quadratrac chain. That's with everyday use in town, and traveling, often with a 4200lb boat behind it, through mountains. People who do a lot of off-roading seem to have to replace that chain (technically called a link belt) about every 30,000 miles or so. It may start jumping teeth in a sudden hard pull, but they never actually break. It requires a special lubricant available only from Jeep dealers (unless something has changed). About 8 bucks a quart, but it lasts a LONG time. These transfer cases are not prone to leaks, from my experience, and last forever. Back in the 70' and 80's, everyone who tried using a different brand of limited slip lube had to replace their chains right at 10,000 miles, so a word to the wise. And another word to the wise-that CV joint at the case end of the front drive shaft MUST be kept properly lubed - it's only about an inch from the side to the transmission, and if it throws, the transmission case is a common victim. It the Jeep in question has the GM TH-400 tranny, that Jeep-special round case is especially hard to come by (they can usually be welded). If it has the Chrysler 727 Torqueflite tranny, there may still be a few readily available. Beefed up 727's are available (or were as of about 8 years ago), but still are not as stout as the TH-400.