I’m thinking of getting later fj80 axles with a e locker and swapping them into my truck, I’ve seen it done before but how easy? I would like to do it myself and I’ve seen a post where someone even ran their same radius arms and Rte springs, and eventually I would like to 3 link front and 4 link rear anyone know anything about that? Also could some aftermarket dual rate 80 series springs work? Saw someone saying that stock front 80 series springs get 4 inches of lift on a d2

 

For the 80 springs""lift " use front 80 springs in the front of your disco and move the disco 2 front springs to the rear.

The 80 6 cylinder motors are heavier than an all cast iron Chevy 350 by @200 lbs if memory serves me correctly. The stock old 80 springs could be old and saggy so lift quality/height might be variable.

 

You'll find that a 3 link in the front is difficult due to the narrow frame rails and dual exhaust from the v8 headers. A td5 with a single side exhaust would be easier to 3link as more room to package everything. If I remember correctly the 80 rear axle the diff is centered so you can end up with some funky driveline angles (I may be wrong there been a while since I looked into this). I don't know that the radius arm mounts are on the 80 are the same size as the disco. It's not as simple as bolt in...

 

The fj80 rear axle is offset to the right side but not as much as a 40/60 series.

 

I couldn't remember exactly, I looked into this a few years ago.

 

This is going to be one of those you either want to do all at once or not at all. You can reuse your radius arms and springs. You will have to cut all the mounts off the FJ axles and clean the axles up. Cut all the mounts off the D2 axles, and weld them back into the 80 axles. If you want to upgrade to 3 link or 4 link anyway, now is the time because you will have to cut/weld mounts again when you get to that point. No sense doing it twice.

Driveshaft will most likely have to be adapted or modified. Depending on pinion length the driveshafts will have to be lengthened or more likely shortened, and the u-joint will have to be changed unless someone makes a conversion yoke.

Brakes will have to be dealt with. It may be that the brake hoses will just bolt to the FJ calipers, or maybe FJ brake hoses will connect to the D2 hard lines. Easy problem to solve even if the fittings are different.

Did FJ axles have speed sensors in the hubs? If not, you will have permanent 3 amigos and no speedometer. If yes, they will need to be adapted. If the tone ring has a different number of teeth that will throw off your reading - usually quite significantly.

If it were me going through the trouble, I'd upgrade to Dana 60 front and GM 14 Bolt rear. More realistically I'd just drop the coin on HD axle shafts and air lockers so it's a bolt in solution. That should be good up to 35" tires which is more than most anybody runs on these. At 3" lift significant body trimming is required, and at any more lift than that significant suspension and drivetrain work is required (though less significant than swapping the complete axle assemblies). Personally I won't go taller than 3" or 4" lift on a D2 - too top heavy as it is.

If I'm going past 35s, I'd probably jump to 38s or 39s. At that point I'm definitely doing 1 ton axles (Dana 60/Corporate 14 Bolt would be my preference) and skipping the FJ axles all together. That is, unless you just live in a place that the FJ axles are far more common than here in the US so you have easy access to more FJ axles and more aftermarket parts.

The D2 front springs in the rear will lower the rear 3".

 

I apologize, I'm a little dyslexic. The fj80 front springs go in the rear of your disco 2. You then take your disco 2 rear springs and put them in the front of you disco.