I recently purchased my first Toyota truck, a 94 4wd, 5-manual. I had heard it is a good idea to lock the front hubs on occasion to circulate the fluid around in the front diff, so I locked them (left the transfer case in 2 high) and tried to move, but it wouldn't

I put it in 1st and gave it a little gas, thinking maybe the gears were just rusted together and would break loose, but the truck would not move at all. I unlocked the hubs and it drives fine.

So I am wondering if anyone has come across anything like this, and if it is likely the front diff gears are junk, or would it be in the transfer case? As I mentioned, I never touched the transfer case selector.

Let me know what you think.

 

I'd start by draining the fluid too see what kind of carnage awaits behind that cover. Look for chunks of metal and dark, gritty fluid. It sounds as if something has catastrophically broken in there. You can also try turning the CV axles by hand, with the hubs unlocked, just to see if the entire assembly is siezed.

On a curiousity note, why didn't you check to see if the 4wd worked before you bought the truck?

 

Check the fluid in the diff

If you didn't shift the transfer case then I doubt that is the problem. Try putting the truck in 4wd low and see if it moves. If that doesn't do it then pull it apart and see whats inside

 

I would advise not, just based on the fact that if there is something siezed, you could only compound the problems by breaking something else. 4 lo amplifies torque, thus, allowing the engine to basically transmit more power to through the driveline, making it much easier to break something. Try to determine what is wrong, instead of the gung-ho, lets just try to break it loose and see what happens approach. That is what keeps me in a job, as a technician.

 

"It wont move"..... As mentioned, you didn't put it in 4WD at all, .... 2H is what it's supposed to be in all the time when not wheeling. So, try to put it in 4H, then lock the hubs in and see what you get, .....but BE GENTLE, lol. When you say "It wont move", are you saying when you give it gas in gear letting the clutch out, .....it will stall?

 

chef has a good point. but like he says, be gentle. Any popping, banging, or any other non-automotive healthy sound, should warrant you stopping and digging a little deeper.

 

Yeah, when the hubs are locked, in 2H, 1st gear, I give just a touch of gas and it is like the truck is against a wall, it wont move. As mentioned, i didn't want to break anything so I didn't push it.

One thing I just remembered, I replaced the front rotors a couple weeks ago, and I remember having to put a wrench on the front axles so i couple loosen that brass bolt in the end of the axle, under the hub cap. So what would it mean if the gears wont go, but I can turn the axles by hand?

 

Tea, ........ You loosened the adjuster nut(about 54mm) that's in the Hub? That is VERY torque specific if that's the case, and might very well be the cause of you're "going nowhere" syndrome, lol. there are springs and such in there, and I'm not sure, but maybe one of them buckled or you caused something in there to bind?(Which might only manifest when trying to lock them in).... But my point, previously, is that "Locking the hubs in....while in 2H=NORMAL 2WD, .... that's not going to produce the 'test run' you're looking for.

However, now that you say what I THINK is, "I loosened the adjuster nut in the Hub"..... I'm leery of you driving it in 4WD at all. Hmmmmmmmmm.

 

if both tires are off the ground and u turn the tire and the opposite one turns means that the diff is working or at least letting the tires rotate. but when u put it on the ground and the front tires wont turn means that ur gears have blown up and are in chunks. to me it is sounding like u need to drain the oil and see what comes out and take some pics of the mess u find.

 

I am pretty sure that bolt is just to hold the end of the axle in the hub.

 

You need to jack the front up and lock the hubs. See if you can spin the tires.....then report back.

 

The 4wd gear shifter connects the front diff to the transmission

The hubs connect the individual wheels to the front diff.

This is a very simple thing to diagnose.

WIth the shifter in 2wd and the hubs UNLOCKED, the half shafts should turn by hand and somewhat freely. IF they do not, something in the diff is FUBAR.

With the shifter in 2wd you can turn the front drive shaft by hand. IF it does not, something in the front diff is FUBAR.

IF you CAN turn the front half shafts by hand, jack the front of the truck up (both wheels off the ground). Lock the RF hub and spin the RF wheel. Unlock that hub and go to the LF wheel doing the same, lock the hub and spin the wheel. Both should turn with the hubs locked. IF one does and one doesnt, you have narrowed the problem down to that hub/diff side.

If NEITHER side turns then its not a hub, its the diff.

However you also need to check the transfercase. Locking the hubs connects the front wheels to the Xcase,, ever though that something in there is binding?

Xcase test:

With the xcase in 2wd and the front hubs unlocked the shaft should turn freely. If it doesnt, you need to remove the front driveshaft at the front diff and see if its the xcase stuck or the front diff stuck. All you have to do is turn the front pinion flange by hand. The pinion shaft should turn, if not, the front diff is FUBAR. if it turns, try to spin the driveshaft now hanging loose, it should spin too. IF the driveshaft doesnt spin, your Xcase is FUBAR.