I'm about half-way through swapping IFS front diffs between my 1999 and 2002 4runners (Man, those diffs are a bugger to get out!), I've got the one from the 2002 completely pulled and sitting on the floor. I went to pull the one out of the 1999 and I've noticed some slight differences between them when I went to unplug the ADD. The ADD motor is a bit different than on the 2002. Different wiring harnesses as well. But after staring at them for a good 30 mins or so and trying to compare them, it appears that the differences are just between the ADD motors only. Though the diff housings do appear to be the same so I'm planning on just swapping the motors between the two diffs. Does anyone know for sure if they are and if this is going to be possible? The other one is almost out so I'll just be pulling it in the morning and trying it out I guess if nobody responds. :-/

In case you're wondering, I swapped the rear-ends between these two last weekend and I need do the fronts now as well to match the gearing--the 2002 (mine, already pretty modified) had 4.10, and the 1999 (the wifes, totally stock) had 4.30 (and an e-locker ).

-Ferg-

 

To answer my own question:

Diff housings, diff tubes, and diff mount arms are the same between [my] 1999 ADD IFS diff and 2002 ADD IFS diff. The ADD actuators/motors however are NOT the same. The one from the 1999 is vacuum operated and the one from the 2002 is an electric operated. They can however be swapper around between the two diffs as the diff housings are identical.

Glad I am not having to abort this project as these diffs are a gigantic PITA to get out.

And one other little note, the 2002 required the diff tube to be pulled off prior to removing it from the vehicle. This is only possible with electric actuator as the vacuum actuator blocks the tube from coming off. Well you could possibly pull the vacuum actuator first and then the tube, but that just adds more pain/work IMO.

-Ferg-

 

Ferg, thanks for the detailed info...good to know when I get around to swapping mine for the same reasons.

Did you pull your diffs on jack stands or a lift? Wondering since some say it's a stupid easy job but others like yourself say it's a royal PITA.

 

One is vacuum and one is electric. They are not swap-a-ble. You will have to convert the electric one to vacuum or vacuum to electric.

Look in the driver side front fender well on the 99, see the can in the front. Now look at the 01-02, No can.

 

Jack stands. And I'm just a little guy so its tough for me to manuever the diff around to find the sweet spot to get them out.

-Ferg-

 

See post #2. Easy enough to convert the electric one to vacuum and the vacuum one to electric, when I've got one of each.

-Ferg-

 

With the help of two great local CruiserHeads, both trucks are all back together with front diffs swapped. Getting the 02 diff back in was again a PITA, but we eventually found the sweet spot. The 99 diff found its sweet spot real quick and easy.

Swap is done and both trucks have been tested to make sure they are getting into 4wd properly and all is well.

Swap complete and successful!

Though I will *never* be pulling front diffs again. LOL

-Ferg-

 

Ferg, about the rear diffs, was the swap bolt on with no modifications? was the swap the whole axle or was it the just the 3rd members? did you also swap the upper and lower control arms attached to the rear diffs? Thanks

 

I swapped complete rear axle assemblies. All control arms stayed with their respective vehicles as they are identical and I find it's easier to move the axle around without all the arms attached.

It was not exactly completely bolt-on. The brake lines are slightly different between the earlier 3rd gens and the 01-02s. The earlier ones have only one brake line coming down in the middle of the axle and it Ts into two hard lines running to each drum on the ends of the axle. The 01-02s have two separate brake lines coming down. It is an easy fix to just swap the hard brake lines from axle to axle (so the brake lines stay correct for each truck), but you do have to drill two small holes in a control arm bracket on the earlier axle for a bracket for the second hard brake line. Super easy to do. See THIS THREAD for pics and further explanation.

-Ferg-