Buying a J20 for drivetrain to put in J4000????

[Joe Inskeep]

Hey Guys,

I have a possibility of buying a '75 J20 with Q-Trac for $1,000. I also have the possibility of buying a '73 J4000 in good shape for about $1,000. Total outlay not including any other work = $2,000. The J20 is all rusted up, but runs and has an open-knuckle, disc-brake front D44 axle, and has a full-floater D60 in the back with the bigger drums. The J4000 is stick-shift and I want to keep it that way. Basically, all I want from the J20 is the two axles and the engine. Is it worth it? Anyone done this before, and what's involved? What do I need to do to convert the J20's automatic hubs to manual ones, if I do the conversion? Thanks for any input!

Joe

[UnkleMunky]

Well....I'm not an expert on much, but from what I've gathered, the D20 case trucks(like the J4k with stick) have a centered rear differential. The QT case trucks(like the J20 with auto) would have an offset rear differential. Apparently offset enough so the angle is too tight to do a simple direct swap. I've heard this on the smaller rigs(waggies, J10s, etc.), but not sure if this is true on the 3/4 tons. You can tell some by looking, but others might know how swappable the D60s are between those rigs.

For the front, I'm also not totally sure how hubbable the fronts are, but I'm "assuming" that most any of the "hub kits" should work for that...as LONG as you're going to not use the QT case with this rig!

Hopefully someone else can fill in more specific answers, but there's a couple points to think on! Wish ya well....



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Michael(UnkleMunky)
'78 J10: 258, 4 speed, longbed, topper
'76 J10: Honcho, 360, TH400/QT
'89 Plymouth Reliant(PluggerMobile)
J-Pages(some of my auto pages) (http://www.eskie.net/superior/j-pages/index.htm)
unklemunky@eskie.net

[BobBarry]

Well, that truck straddles the change in frame and suspension, so the axles may not (probably won't) be a direct bolt-in.

How is the frame on the J-20? If it's in good shape, the J-4000's cab and bed would swap over. You could use whatever transfer-case you'd like with that offset rear-axle; the angles won't matter.

If you did go with the D20 transfer-case, you wouldn't have to install locking hubs up front; it would work just fine with the permanently-engaged hubs. Installing the locking hubs would let you unhook the whole front driveline so it didn't spin when in 2wd mode.

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Bob Barry<UL TYPE=SQUARE>* '78 Cherokee 4-door
* '88 Grand Wagoneer[/list]http://studentweb.providence.edu/~rbarry/wheels/

[scotty]

the qt d60 is not really offset that much,and the driveshaft angle is actually prolly worse with the qt than with a center output d20.

cant give specifics on what it would take(spring perches,shockie mounts,etc.) but i can offer that the offset will not be enuff to bother a long wheelbase j truck. also the front hubs are not automatic,they are full time drive flanges and ll you need to do is remove em and replace with any hub designed for an "internal mount" dana 44.

look thru the "455 j20 project" pics on the following site-theres one of the rear d shaft on a factory qt j20 with the bed and cab off.
http://home.off-road.com/~jseries/

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scott
85 grand wagoneer
258 with motorcraft 2bbl/t18/spicer 18 with pto/widetrac offset d44s/rear discs
38x15.5 gumbo mudders
snorkel/dual batteries/onboard air/"custom" convertable
3 inch body lift/mostly stock suspension/"modified" fender openings
custom front/rear bumpers and brushgaurd

vw turing brake,BIG tow truck PTO winch and full roll cage install very soon
4.0 aquired-4.5L stroker someday...

now we can do some 'wheelin!