'96 4Runner, how does the front axle work? (1 Viewer)

[mabrodis]

A buddy just bought a '96 4Runner, got it from NY, not a bad vehicle, fair amount of underbody rust, but overall looks nice. Has 160K miles, PO said timing belt had been changed. (my buddy's dad bought it for him, so the fact that it wasn't perfect with low miles wasn't really a concern, since it was free for him)

He brought it to my house and we put it up on jack stands, looked at it, pulled front tires off, etc. If I spin one front tire, the other spins the other direction (normal open diff behavior) (I think that's what happened, kinda forgot now). However, if I spin the front driveshaft NEITHER front tire spins...the front driveshaft just spins freely. I was under there and like WTF...it all looks ok under there, but I'm baffled. Is there some disconnect point that would let the front driveshaft spin without spinning the front tires? Maybe the diff is jacked, missing a ring-gear (only thing that would cause this, since the pinion is there (pinion driveshaft flange))...I didn't know what to tell him, just said I had never seen that before and had no idea what was going on.

Any ideas? (please tell me this is normal, I don't really want to tell him something is jacked)

 

[KliersLC]

I believe this is normal. My 94 4runner and 95 T100 have the ADD system and I assume that the 96 does also. Here is some more info. http://www.off-road.com/toyota/tech/add/

Good luck and if all else fails, take it into the mud and see if the front axle works

Dan

 

[mabrodis]

Ahhh...ok, thank you!! I was worried and yeah thought about the mud romping, but don't have any mud close and if it didn't spin the front tires...eeeek...

I've never heard of disconnecting the axles that way, makes sense (apparently my remembering one tire spinning one way and the other spinning the other were wrong)...

Thanks!
Mark Brodis

 

[Cube Dweller]

Mark, when I bought my '91 I found some good links thru the Marlin site explaining ADD. Basically it's vacuum actuated. If it doesn't have disconnects/manual hubs AND it's a 4x4, it's got ADD.

I swapped my front dif w/ a non ADD version w/ a true trac and converted to manual hubs. I didn't want to be dependent on 20 ft of vacuum hose to ensure it went into 4wd. Plus w/ the ADD, I believe(but am not sure) one side/CV will always be turning.

 

[KliersLC]

The best part about ADD is crawling down into the mudhole you are stuck in to try and reconnect the Vaccuum hose

It didn't happen on a toyota though......................Chevy S10 blazer. One of the top ten POS's in the world

Dan

 

[KliersLC]

If it doesn't have disconnects/manual hubs AND it's a 4x4, it's got ADD.

Well........ I was thinking (dangerous I know)..... and if its a toyota then yes, but IIRC the early 80s 1/2 ton chevy suburbans had an auto lock system that locked the front hubs threading a large coarse threaded bolt from the axle end into the hub. After shifting to 4x4 it would thread in and lock up and when you wanted to disengage you shifted into 2wd and backed up 20 feet until hearing a clunk. It seemed like an ok system, mine didn't have any problems till I rolled it

Anyway, someone please correct me if I have this wrong

Dan

 

[Mad Chemist]

From what I've gathered, with ADD your CV's are always spinnging. There isn't any need to go in reverse to get out of 4WD, I can shift on the fly (more or less) in and out of 4 HI.

 

[KliersLC]

The old suburban system is not ADD, and for the old chevy system you do have to back up. The CVs do spin, solid connection from hub with ADD