4WD Problem

[CO71Blazer]

I have a problem with the 4WD in my 71 Blazer. When I lock both hubs and put her in 4Hi my right front tire locks. It just drags and does not roll. I've pulled the hub apart and can't see anything obvious. The Warn Premium hubs look to be in working order. Wheel nuts are torqued to spec, and on jack stands everything appear to turn correctly. My brother thinks I have a diff issue in my D44. I know the front drive shaft needs to be rebuilt but I'm at wits end, and three wheel drive is not going to cut it. I need to pull the cover off the front differential and take a look, but I wanted to see if anyone had any ideas before I just tearing things apart.

[franken]

The driveshaft is common to both sides, so it's not the issue. It's between the diff and locking hub. I'd guess it isn't the diff, which leaves a seized bearing in my tiny mind. I'd pull the hub and axleshaft. If it's locked when driving, and not on jackstands, that seems odd. Is it locked going forward and backward?
Remember pulling that crap apart isn't as easy as the manual says. Some parts stores allow you to borrow the spacial lock nut socket and hub puller.

[CO71Blazer]

Bearings are all good, I just changed them. I'm thinking I have a bad hub as it works fine in 2WD. But I've been wrong before...

[Big Al 1972]

With a open differential power goes to the tire with the least resistance.

[Blazerowner]

It might be binding in the hub if it’s not fully engaged. I’m trying to picture it when I rebuilt mine. Is the hub all the way on the splines where you can put the c clip on to hold it in? I remember I had to use a pry bar to pull the axle forward to get the clip on. In my mind if it only does it when you engage the hub that could be your issue. I think the hubs are a little finicky when first installed.

[CO71Blazer]

I pulled the stub shaft out to get the C clip on the end, I've taken it apart and put it back together a couple times now. I'm really at a loss, but I don't want to have to pay a shop to take a look at the front end. I'll most likely end up replacing the hubs as they are almost 20 years old at this point. Man, I've had this truck for a while now...

[Blazerowner]

That’s what I would do just try another set of that doesn’t work it’s like something else. I’m the same way, I would rather figure it out myself.

[grillzy]

It wont be the warn hub. Engaged or not it would act the same. Sounds like a diff issue. Wheel turns fine in 2wd?

[CO71Blazer]

Yup, everything works fine in 2wd.

[CO71Blazer]

Ok, so I just tried something in the snow patch out front. Hubs locked, in 2WD everything works fine. Shift into 4WD and the right front locks up...

On a positive note. My 350/SM465 has enough power to push the locked wheel along... So there is that. And that kids, is how daddy breaks things.

[mister.freeze]

the hub is NOT the problem. on jack stands, lock the hubs and put the xfer case in N. Turn the front shaft by hand. I bet it turns the left wheel. Have a buddy hold that wheel and turn the shaft. RT wheel SHOULD turn. Bet it doesn't. your problem is in the Diff. Should be obvious when you pull the cover.

[Jesse B.]

It could also be the axle shaft. If the above test does not spin the tire, check to see if the axle joint is hitting something, perhaps hitting one of the ball joints.

[Jesse B.]

Originally Posted by CO71Blazer

Ok, so I just tried something in the snow patch out front. Hubs locked, in 2WD everything works fine. Shift into 4WD and the right front locks up...

On a positive note. My 350/SM465 has enough power to push the locked wheel along... So there is that. And that kids, is how daddy breaks things.

Actually, if the hubs are locked, and everything works fine, then that shaft should be turning. If so, I second Mr. Freeze. Something is probably wrong with the carrier (diff).

[mister.freeze]

Disengage rt hub and put in 4wd. What happens? WARNING: risk of breaking something! This should free the rt side and add resistance to the left

[cleszkie]

Do you have the same gear ratio in both front and rear axles? Sounds like you might not.

[CO71Blazer]

I'm going to pull the cover tomorrow. Today was my Friday... They are both 3.73.

[kwmech]

Put the front axle on jack stands. Turn the front drive shaft by hand and see what the axle shafts do.. They should both turn evenly. Lock the hub on the right side only. Turn the tire by hand..what happens. Do the same on the other side. Report back..or drop the cover off and take a look....probably needs an oil change anyways

[cleszkie]

My money is still on mismatched gear ratios in the axles. Blazer probably had a drum brake front end and somebody swapped in an entire axle with disc brakes with different gear ratio.

[kwmech]

He can verify when he pulls the cover