So I have a 94 sr5 pickup and it just blew the head gasket in the 3.0. Wanted an upgrade so I went with the 3.4L. a good friend of mine is doing the work and he calls me the other day to ask about my hubs. Apparently it has auto locking hubs that are after market but the wiring isn't hooked to anything. I've never had any problems going in or out of four wheel drive. I'm just worried that maybe my hubs are all the time locked in. He's doing research as well and I'm sure he will figure it out quickly but any help on here as well would be great

 

I've never heard of auto hubs on 89-95 4runners or trucks. Factory options were manual hubs or drive plates(locked all the time) with an automatic differential disconnect system which unlocks the axle shaft at the differential. The wiring would only be on ADD equipped models going to the solenoid at the differential http://personal.utulsa.edu/~nathan-b...26addcontr.pdf

 

This is spooky a person doing a 3.4 swap has no clue what hubs you have.

Granted it is a Toyota it is possible someone installed automatic hubs not to be confused with the ADD system.

Get some pictures !!

Have at any time have you needed to lock or unlock your hubs??

Just shift your transfer case into 4high and go??

Could be the wires your (mechanic) sees are for something removed before you bought the truck.

 

No true auto hubs (the kind that actually bolt on to the wheel hub) that I've ever seen have wires going to them. They operate purely on mechanical principles, generally fairly clever and somewhat complex and unreliable.

A stock 94 pickup almost surely has ADD (automatic differential disconnect), which involves wires and vacuum lines going to a sliding collar in an extension on the drivers side of the front differential. As mentioned, the wheels themselves will have drive plates which lock the wheel to the CV axle. The CV axles and the spider gears in the diff are always turning. The ring, pinion, and front driveshaft only turn when 4wd is engaged.

The ADD system is a good system for most people. It allows easy on-the-fly shifting to 4wd, and is less fussy about lack of maintenance than are manual hubs. Switching to manual hubs will do almost nothing for gas mileage, and probably the rubber on the CV axles will rot from age before the joints themselves wear out from the constant turning. That's what happened to mine.

 

No my buddy has a dedicated Toyota guy working with him for the swap but the guy has been out of town for a few days. He probably already figured it out with the hub issue but it is just scary for me having driven my truck for this long. I've never had any problems going in or out of 4WD and haven't had to lock or unlock anything. The main reason I brought the issue here is because he knows the factory hubs aren't on the truck and there was loose wiring. I'll post some pics soon showing it.

 

There's nothing "scary" about driving your truck even if the hubs never do unlock. As long as the transfer case is in 2wd, you're fine driving around on hard pavement. The only thing locking hubs (manual or auto) or ADD do for you is to stop some of the components (front drive shaft and ring and pinion) from turning while in 2wd for slightly better mileage and a little less unnecessary wear and tear. Assuming the front drive shaft is balanced, as it should be, there's no harm in driving 75mph down the freeway with the front hubs locked, as long as you're in 2wd. All-wheel drive vehicles do it all the time.