TJ won't engage front axle

[BakedAlaskan]

I sure didn't feel that I was far behind anything mechanical but I'll be damned if I could answer this simple question. My buddies TJ won't engage the front axle. Oh that's simple, I popped under the axle to show him. Well I saw nothing, nada, zilcho..................How in the heck does this engage the front axle?? Obiously no hubs, but no way to lock the differencial in??
The transfer case shifts in and out just fine, driveshaft spins when it is "in" 4x but nothing at the axles.

Anyways I won't guess anymore I need this knowledge to save me from loss of sleep.


Thanks guys

 

[L33TJ33P]

Wasn't going to answer but I will just say two words.

Vacum Hose. Just Guessing. Don't really know that is one place I haven't delved into my TJ.

 

[Joopin]

That just happend to my YJ... I thought it was the vacuum too but it ended up being a cable got disconnected from the transmission to the t-case. I had my mechanic do it since he was working on the rear main at the time. That's all he told me he did. So now you have 2 things to look at!

 

[west747]

you can also check the vacum motor hoses or if all else fails take it off and inspect it, check to see if it is working, clean it up with some wd-40 and bolt her back on.

 

[Snitty]

a TJ has a solid axle... there is no vacuum disconnect... no vacuum.... if the driveshaft is spinning... the front axle should

 

[Bounty__Hunter]

Yep, no vacuum to engage the front axle in a TJ, that's only on YJ's and some XJ's (not to mention some SJ's, GM vehicles and others).

The TJ front driveshaft will spin even in 2wd, simply because there are no hubs to unlock or vacuum disconnect. If his 4hi and 4lo will engage, he's got 4wd and the front axle will pull. If he can't fully engage 4hi, N, or 4lo, the transfer case linkage needs adjusted.

 

[BakedAlaskan]

Thanks guys, like I said I was stumped because it made no sense to me. If it has NO hubs, No switching mechanism at the differencial, then the drive shaft HAS to spin with the axle. And is simply disengaged at the transfer case. (Very 77 chevy full time 4x4-ish with a slight twist) But here is the deal.
He has 410's and ARB lockers front and rear. The front drive shaft does NOT turn when in 2hi. It DOES spin when in 4hi/lo. Even locking the ARB he can spin tight dounuts on pavement without any resistance from the front axle. Obviously the ARB isn't locking since with it locked the wheels should have fought him when turned so sharp. Something had to have failed with the ARB internally and is allowing the pinion to spin freely from the axle shafts??? Even with the locker not locked it should be able to work at least one wheel. So Yea I am stumped without tearing into it and see just what failed. I was hoping there might be this secret "TJ Thang" that we missed and I could slap my forhead and SAY DOH!!!!!!

Guess not though. So I guess we will throw it up on the lift and tear into her. If the ARB failed I will be OH SO UNIMPRESSED, since I know how he treats this thing on and off road.

 

[Snitty]

Tire load/pressure charts

does he not have a stock powertrain/drivetrain?

 

[jeepin916]

no vacuum hose on TJ's the front axle is one piece, with the drive shaft it is connected at the transfercase, when you pull the lever into 4wd the transfer case connects the front drive shaft, it is a gear in the Tcase, now unless your tcase is messed up when ever you pull the lever into 4wd it is locked in... if u wan tto test it out and see if it is working jack up the jeep and put jack stands under the front axle and rear axle make sure ALL 4 wheels are off the ground, then put it in 4 wheel drive and put it in gear, the front tires should turn ans so should the rear tires.....

 

[Bounty__Hunter]

Pretty sure the ARB acts like an open diff when unlocked, so the front driveshaft will not spin in 2wd, or may spn slowly due to parasitic drag.

The front driveshaft will spin in any 4wd mode because of the transfer case sending power to the front and rear.

If he's able to turn that tight on dry pavement in 4wd with little resistance, the ARB is not engaging. They're problematic at best.

 

[jeepin916]

hey bounty on the TJ's the front drive shaft spins weather its in 4wd or not thats becouse its constantly locked to the front axles

 

[Bounty__Hunter]

hey bounty on the TJ's the front drive shaft spins weather its in 4wd or not thats becouse its constantly locked to the front axles

Okay, I was thinking of the open diffs affecting this, but that's only if you can disconnect one or both hubs. Thanks.

 

[Snitty]

whether open or locked... the tj front shaft will spin because of the carrier spinning from the wheels moving.... but... with the tires in the air... ONE tire can spin without the shaft moving