front diff swap - vacuum vs. electric
 

I searched on this but couldn't find anything. I am getting ready to swap a front diff (with an ARB locker) into my '98 ADD equipped Tacoma. The diff I am installing is a '01-'04 ADD diff. It is my understanding that the newer diffs use electric actuation, whereas the previous models use vacuum actuation.

SO, my question is - does anyone know if the actuators can just be swapped out. In other words, I remove the elec. unit from the ARB diff, and install my vacuum unit onto it?

Any info is appreciated.

Just a guess here but I would imagine that the mechanisms themselves won't swap over. However, the complete axle tube assembly that contains the mechanism (see pic, no ADD but you get the idea) will. The differential housing itself did not change from '86 to present (as far as I know).
http://home.mho.net/toy283/image1.jpg

If you find it necessary, swapping the axle tube should add less than 30 minutes to your install time. The axle housing is bolted to the 3rd with those wierd headed bolts, so make sure you have a E12 TORX external socket in hand before doing the swap.
http://images.amazon.com/images/P/B0...F.MZZZZZZZ.jpg

Don't forget to seal it up with some RTV.

Here's a pic of our IFS 3rd with the passenger side axle housing removed:
http://www.geocities.com/transalper/...locker-arb.jpg

Have fun with the ARB! How many spare CV axles are you gonna carry? :)

Hey guys - thanks for the replies. I haven't been able to confirm the dimensions on the mounting points, etc. but it looks as though your idea is correct - just swap my vaccum actuator and axle tube with coupler onto the ARB locked diff. I guess my only concern is if the coupler is the same. I could definitely live with 30 minutes of extra time to swap the tubes out. :D

Thanks for the heads-up on the TORX socket Transalper! (BTW, the pic link goes to an error page)

As for extra CV axles - I have 3 spares. Beyond that, the SAS will have to be implemented :D

UPDATE

I got my diff swap done on Saturday. I was able to swap my vacuum actuator to the 01-04 elec. actuated differential with no apparent ill effects. Despite a slight difference in the casting of the mount for the shift forks, the shift forks were the same. My vacuum actuator bolted right on. I still don't have my air lines or locker switch installed, so I won't be able to do a 100% test until then. But for now, the 4WD indicator light comes on when I shift into 4LO or 4HI. I haven't driven it in 4wd yet - don't want to until I get the ARB hooked up. So everything looks good so far.

Something to note - my diff did NOT just "drop out" like all of the write-ups I have read said it would! It was a PAIN IN THE BUTT! Maybe it is because I have a '98 manual trans. V6, but after getting all of the mounting bolts removed, it would not come out. The pinion flange was either hitting the transmission or the steering box depending on which way we moved the diff, and then the front of the diff was hitting the oil pan before we could clear the pinion flange. The bottom stud kept hitting the top of the cross member too. We had to REMOVE THE PINION FLANGE and the front mounting arms to get it out of there!! :scared: And we had to remove the pinion flange to install the new diff. It sucked :(

I took some pics...

Here is where the pinion flange was hitting (red arrows) and the yellow circle shows where the lower mounting stud was hitting the crossmember.

http://www.bajataco.com/arblocker/arbfrontlocker01.jpg

Here is where the front of the diff was hitting the oil pan

http://www.bajataco.com/arblocker/arbfrontlocker02.jpg

The two diffs side by side. The vacuum on the left, the elec. on the right.

http://www.bajataco.com/arblocker/arbfrontlocker03.jpg

The two actuators side by side

http://www.bajataco.com/arblocker/arbfrontlocker04.jpg

The two shift forks (side by side). These move the coupler sleeve that either engages or disengages the 4wd on an ADD IFS diff.

http://www.bajataco.com/arblocker/arbfrontlocker05.jpg

A HUGE-MONGOUS THANKS to Mark, crawler#976 for helping me on this!!!

:banger:

After removing the pinion flange, things went very quickly. Being very familiar with a solid axle, I guessed there would be a torque spec to re-install the flange.
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so, I didn't even check Chris' manual. DOH!

The procedure they listed was hideously complex.....

and since I'd already pulled off the flange, it was a moot point anyway. After calling everyone we thought might know what the spec was with no luck, we got an answer from the independant Toyota Service shop in town. Whew!!!!!!!!!

Their manual said to torque the Pinion Flange nut to 56ft/lbs. We felt pretty good about it when the old staking point lined up perfectly.

Thanks for your patients Chris- I learned a bunch about Taco front ends! For the most part, it was really an easy project, it just took a little longer than I'd figured. I'm guessing the manual tranny bell housing is a bit wider than an auto.....

later

Mark, thanks again!!! I appreciate your patience since I wasn't entirely ready on Saturday morning. It was a pretty fun day regardless. It looks like we finally got that rain and snow they kept talking about :bounce: Need more snow though - it's a pretty weak cover...