me either, I'd looked at the thing a thousand times but it didn't sink in until I pull it and tried pulling the ADD assemlbly off to put it on the new one. An emergency trip to the Sears hardware store and $30 later I was in bidness. luckily the wife was home that day, otherwise it would have been up on blocks for a couple of days.

 

Yep, Dave is right on that. There isn't any difference between the front 3rds from the V6s and the 4 cylinder version. The rear is a little beefier.

 

 

Sorry, I missed your first post. Will my little "4WD" light still light up on the dash without the ADD gear? Simpler is definitely better IMO. So it's a step up to pull the ADD?

You've all got me reconsidering about returning them both...

 

heck yea it's a step up. eliminating the drag of the cv's will up the mpg. you could always just hardwire a switch to the light and when you engage 4WD just hit the switch to make the pretty light come on.

 

Am i missing something here? Won't he also have to replace the hubs and axles to stop the helf shafts from turning. Sounds to me like if he installs the new tube, his diff will be spinning all the time. Please alaborate.

 

I have manual hubs already. I'm a little sketchy on what ADD actually does. I mean, if I pull the lever into 4Hi, power goes to the front end. Seems simple enough.

 

you beat me to it, I was about to pipe in and say that.

the ADD is acuated by vacuum. when you shift into 4WD the vacuum pulls and shifts an arm over which engages the front diff from the tube side of the diff. the cv's are always spinning in 2wd it's just that the diff is disconnected in 2WD, hence the ADD, automatic disconnecting differential. so installing the manual hubs will unlock the wheels from the cv's, effectively eliminating the need for the ADD system so it can be removed. since Mike already has the manual hubs he can just swap the tube for the longer one and remove the ADD assembly or just permanently lock the ADD. there's a page on the Wire that tells how to do this. Mike you should browse on over there in the toyota section and read up on it, I think it explains the mystery of ADD a little better than me.

Here's the link:
http://www.4x4wire.com/toyota/tech/add/

 

Ahhhh..makes more sense now.

 

Just put in the non-ADD diff and manual hubs. You will end up with a less problematic front end.

 

I had read up on that a LONG time ago. Thanks for the link, I need to revisit it.

Here's a wrinkle though. Throughout the winter, I keep the hubs locked so the Mrs. can just pull the lever and not get her pwetty wittle hands dirty. If I lock the hubs on a non-ADD diff without the lever pulled to 4WD, what is going on with the driveline?

 

Advice for the "wittle hands": toughen up there toots! - You can also get a tool that I think Warn makes that makes it easy to turn the manual hub locks with gloves on. basically it's a plastic cylinder with a slot in one end to grip the lock handle. I think 4WP has them.

Q2: with the manual hubs locked, the cv's will spin, the diff will spin (since the ADD is now fulltime engaged), and the front drive shaft will spin, just like a regular 4x4 without ADD. the part that isn't engaged is the t-case. once you shift into 4H or 4L, the t-case engages the front driveshaft (well, through the output shaft) and then your good to go. shift back into 2WD and the t-case disengages the front driveshaft. then, unlock the manual hubs and the wheels are disconnected from the cv's so none of the front driveline spins any more. with ADD the hubs always turn the cv's, even in 2WD, that's how come they blow the boots when lifted.

 

Crap! I have a spare third that disasembled, and ready for the gear swap, but I don't think it has the ABS sensor.

I'm glad I learned yet another good thing from this board, I would have been livid if I would have used the wrong housing.

Back to the drawing board. I've also been scouring junkyards to find a spare front diff, but no luck as of yet.

I guess I'll just put off the gear swap until I have everything I need.

Ceb, I thought I read on another board that the 4WD light will still work if you keep the non-ADD diff, I think the indication is from the transfer case (the same switch that tells the VSV's to apply vacuum to the ADD to do it's thing)

 

Keep in mind, that you can use diffs out of either 4 cyl or V6 rigs. THey are all the same (per Toy283)

Well, I'm still on the fence then about this. Even if the light still works, I don't like the idea of the front diff/driveshaft turning all the time. I guess it is simpler, but my mileage is bad enough now. The less friction the better.

 

I have been away, now I am back again.

Take the diff in the pic. Install it. Lock the hubs for winter and leave the t-case in 2wd. All that will spin are the spiders.

Take the diff on the truck. Leave it. Lock the hubs for winter and leave the t-case in 2wd. All that will spin is the passenger side spider gear.

Get rid of ADD. All it does is slide the collar. If one of the lines poop, you have 2wd. You have a chance to do it.

I forget if you need to short the wire to the indicator light or what, but that part is straightforward IIRC.

 

Adrian,

Thats' what I've decided to do. Thank you for explaining it like that. I now completely understand.

BTW, I got the front diff for $1.00