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Thread: 1978 J-20?

  1. #1
    Flipsalot Guest

    1978 J-20?

    Can anyone tell me anything about the J-20 trucks?Like what axles,tranny(stick)and if any of this can be used for cj size has a ford 360 in it is all I know.Can get it for 300,it runs.Thanks,

  2. #2
    ROK HUGR jefe Guest
    I looked in my book to see what it has and came up with:
    front D44, open knuckles, rear axle: it is not clear what it has in the book. Can you look at it? On the top of the rear axle housing it will be cast in "60-2" in large characters if it is a 60. Does it have 5 on 5.5" lug pattern? If the rear axle is full floating (big stickout metal hub with bolts, and 8 lugs) it is a FF'60'. You can also check the ratios with a small metal tag attached with one of the cover bolts.
    Some of the lower GVW J20's actually had D44 rears. Make sure. The ratios were not that great either. The stock ratio, because of the ever tightening CAFE standards, was 3.73 with the option of 4.09.
    You say it has a Ford 360. Ford didn't make a 360. AMC used a 360 in this year and all the way up to '91. Chrysler also had a 360 at this time, but it's an entirely different engine. All had carbs, not fuel injection.
    There are 3 possibilities if it's a 4 speed truck transmission: a wide ratio T18 or a close ratio T18. Actually around this time the T176 was available on the lighter duty applications, so check that possibility out. Let's hope it has a D20 not quadratrac. If it has Q-trac, don't even buy the truck. The rear axle will be offset to the pass side w/ Q-trac.
    I would say if it has the wide ratio T18/D20 and a AMC 360 in good condition, you could swap that whole thing into your CJ8, as some on this board have (or have threatened to). If it's the close ratio, D44's, not D60, or has Q-trac, it's not worth it.
    I assume you read my J-4000 rambling post. It had all the right stuff for striping.
    regards, as always, jefe

  3. #3
    panthercj Guest
    I think all J20s had the full floating, 8 lug, 30 spline D60 rear. Either centered diff with the dana 20or off set to the pass side on the QT. Also the T176 started after 80 in front of the NP tcases so if it's a 4 spd, you probably have the T18. The input shaft on these is like 15" apposed to the usual 10" or so because in the FSJ, they had to move the shifter back so it wasn't under the dash. But the front would be a HD44 with 8 lug and hubs with dana 20 and none with QT. Check out this for more info -

  4. #4
    CJ8BarryS Guest

    Buy it

    I would buy it for sure, Can be a great truck just fixing it up. I got one for $400 but its an '86. The drivetrain would be sweet in a CJ, axles would be really wide though. Should be 44/60 axles, tranny should be T-18. It could be a Ford 360 (they did make them for trucks- part of Fords FE line of engines) but it probably is an AMC 360. Buy it

  5. #5
    Flipsalot Guest

    Re: Buy it

    Yeah I read your post on the J-4000..good reading!Yeah,I'm thinnking motor and most of the drive-line swap from this truck.It has the 8 lug floaters on it..the guy says it has diff lockers in both the axles.I havnt looked at it closely yet,its a a guys at work.So it would be no good if its a 60 in the rear?Or only if its offset?3.73 would be a great inprovement over the 2.73 thats in there now..

  6. #6
    sweetscrambler Guest

    Re: Buy it

    Dana 60 VERY good.... offset Dana 60 bad...


  7. #7
    Rod 82 Guest

    J-20 stuff

    Actually, if you take a close look at the Dana 60 under a J-20 with a T-18, you will see that it also has a bit of an offset to the passenger side. I don't know why this is exactly, but the rear driveshaft on a J-20 is about 5' long, so driveline angles aren't going to be much of an issue. As far as the QuadraTrac goes, I really like it on my J-10. I happen to like the stability the QT seems to provide while towing, hauling, and daily driving (when gas is cheap). BUT, it's definately NOT a trail machine.

    Just my .02


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