Quadratrac

[fanojeeps]

Ok, last weekend I got my "new J 10". Very solid truck for $550.00. '77 with a 360, TH400, Quadratrac. Also came with factory brush guard, factory roll bar, and razor grill in perfect condition. Lucked out with almost new 31x10.5x15s. Can someone explain the quadratrac to me. What I know from reading in the archives and my copy of "Jeep J-Series Pickups" is this:

QT is a full time 4wd
Having a lo range was an option
I don't have a lever under my seat therefore I don't have lo range

How can it work full time?
What exactly is the emergency switch for?
Is this the best 4wd system on FSJ's?

I also have an '80 J10 but it has a 258 with a manual 4 speed. How hard is it to swap in the 258 and 4 speed into the '77 as the tranny is bad?

Here are some pics:
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&category=6286&item=2406460881

Fanojeeps

[Lindel]

It works full-time because it has a limited slip differential, unlike a part-time, gear driven or chain driven case with what amounts to a spool. The limited slip allows for some slippage between the drivin wheels, and won't bind up. A part time case doesn't allow for that slippage, and if the binging isn't relieved by loose terrain, then you get to hear loud, expensive noises as your drive train goes BOOM!!

The emergency switch allows you to "lock" the differential, and from that point, it will act like a part time case. Emergency (or E-drive) is for just that, when you can't drive out of a situation.

As far as the QT being the best system, that's personal preference. I like it, but it takes more maintenance that other transfer cases. It needs regular fluid changes and the fluid is fairly expensive, on the order of $6 - $10 per quart, and you need 3 quarts.

I'm afraid that to do the swap, it'll be very labor intensive, since the QT won't mount to anything but a TH400, and the drivetrain out of the 80 will have the wrong setup for the front axle in the 77. The motor mounts are different between the two engines, so you'll have to swap motor mounts too. It's doable, but not easy.

[fanojeeps]

Thanks for the info "perfessor". So I would have to swap the whole tranny, engine, mounts, t-case, and axles to make it work? Also how hard is it to find a TH 400 and what are the years that will work on a '77?
Fanojeeps

[J4GRAND]

Just because you don't have a lever under the seat doesn't mean you don't have low range. Look at the back side of the QT next to the rear output. If it has a flat, saucer-looking plate; then no, you don't have low range. If there is a unit sticking out with a shift linkage on the side, the you have a low range and the shifter is missing. Bought a 78 that didn't have the shifter but had low range. It was a bummer having to get underneath it to shift the low range.

[Lindel]

TH400's are relatively easy to find, the trick is to find one for an AMC. One option is to pick up a chevy or BOP (Buick, Olds, Pontiac) TH400 and swap the goodies into your AMC case (the internals are the same). The TH400 was used in FSJ's from around 70 to 79, but the AMC TH400 ran from 73 to 79. The earlier editions were billed as a "universal", and used an adapter ring.

To swap a complete drivetrain from a 80/later into a 79/earlier FSJ is a real bear, because the front axle is involved. 79 and earlier use a passenger side drop tranfer case/axle, and 80/later use a driver's side drop. The next issue that you would have to face in your situation is the I6 vs the V8. The I6 is physically longer than the V8, so the entire drivetrain has to be relocated, including the motor mounts.

Replacing/rebuilding the TH400 is really your best option, as long as the vehicle is in relatively good shape. Besides, that way you get 2 FSJ's! :D

[J4GRAND]

Lindel,
I love it when I can contradict the "Professor". The AMC specific bellhousing on the TH400 was used from 1974 to 1979. My 73 TH400 still has the universal bellhousing and adapter ring. I used to get in trouble all the time in college arguing with my professors....

[Lindel]

Ok, so I missed a year, couldn't drive then anyway!! :D

My 73 has a T-15/D20 (mostly), and no engine, but there's plans in the making!! ;)

[J4GRAND]

Lindel,
BTW, I was almost down there a couple of weeks ago but then plans got changed- normal for a corporate pilot. If I'm ever down that way, listen for a King Air 586TC on the freq. I'll be asking for ya.

[Rande]

J4grand, the early bellhousing pattern isn't "universal". Its the old Buick "Nailhead" engine bolt pattern that Buick used before GM mandated the BOPC pattern for those divisions. There is a universal pattern bellhousing that has both the GM patterns (Chevy and BOPC).

Thats why early trucks with the Buick 350 engine still need an adapter to bolt up to the tranny. Wierd that you need an adapter to bolt a Buick engine up to a Buick tranny.

[ April 22, 2003, 06:44 PM: Message edited by: Rande ]

[momerath]

I have a '73 Wag with the Quadratrac and my low range selector is a T-handle mounted on the dash just to the right of the steering column, handily labeled, "LOW RANGE". So check your dash before you write it off as handicapped.

[J4GRAND]

I believe 75 was the last year they used to cursed "T" handle for low range. Mine originally had that and it was broken at the QT shifter with the xfer case in neutral. One of the reasons I got my rig cheap, the owner thought the tranny was blown up.

[Lindel]

Patrick, I'm not a controller, but a Navaids tech. If you ask the tower will let me know that you're here though. Anytime you're in the area, let me know. If you have the time, we can get some coffee, or eats, whichever! ;)

[jeepguzzi]

Hey,fanojeeps!! I might have a tranny for you!!

What is wrong with the one you have?? You could have it rebuilt very inexpensively if you remove and replace it yourself!!

I have one that I took out of a parts jeep a few years ago. It had sat for about 5 years, and that was about 4 years ago. I never drove it, so I would not bet on what kind of shape it is in. If you are going to replace a tranny, you might as well pull yours and get it rebuilt. You don't want to know about swapping everything over. It would be a major project, whereas the tranny rebuild would be a weekend or two, at the most!!

You could get one of my trannies, rebuild it, and then do a swap in one day. Not too hard if you have the help of someone who has done it before (wink wink)!!

[fanojeeps]

Jeepguzzi,
Thanks for the offer. I found a tranny attatched to a lo range QT (which I don't have) for $150. I'm picking it up at a swap meet in Jefferson on Sat.
fanojeeps