Front Disconnect Problems

[Bay Wolf]

The disconnect was tight to the oil pan, and the bolts were torqued to spec.

I greased the intermediate shaft splines before replacing the disconnect, but I can't say I inspected them all that closely. The end of the shaft wasn't smooth, that's for sure. I'm pretty sure I had to adjust the disconnect so that it would slide onto the intermediate shaft properly, too. I know I had to turn it to get it to seat properly in the oil pan recess; I assume that was to line up the splines.

[Bay Wolf]

It sounds to me like the splines on your intermediate shaft may be stripped

Could it be the half shaft splines? After closer examination of the old disconnect, the outer gear splines look pretty well worn. I wish I had looked closer at the CV shaft now; I suppose I didn't since I didn't remove it completely.

This picture in the disconnect article shows the inner gear splines where the intermediate shaft enters. Are the outer gear splines where the half shaft enters supposed to look like that right at the edge of the gear? The ridge of the spline almost extends to the edge of the gear. My outer gear is not like that, at all.

[fishsticks]

The outer gear should be more contoured to ease the installation of the CV axle.

[Bay Wolf]

Like this?

That ring goes all the way around the bearing surface. Would it need to be replaced?

The inner and outer seals were shot. Would that allow the internal parts to slide back and forth when you flip the assembly over? The middle thrust washer doesn't lay flat anymore. The fork also has some visible wear, I think.

After some sleep, it makes sense to me now why you said it would be the intermediate shaft. If it was the CV shaft splines that were worn, there should be some slippage (or ratcheting, as you called it?) when rotating the tire in 2HI, right?

[fishsticks]

Those pieces don't look bad at all! Buy some bearings and thrust washers and rebuild that....or sell it to me! I have some extra rebuilding supplies sitting here.

[Trail X]

Let's go through the flowchart, with the new disconnect installed...

(1) In 4HI and with passenger tire in the air, will it rotate?

--Yes, but with resistance, sometimes to the point of not rotating.

(2) Does the prop shaft rotate?

--No; it only moves a slight bit (less than 1/8th of a turn) when the direction of the tire rotation is changed.

(3) With both tires raised and in 4HI, does the driver side tire rotate when the passenger tire is rotated?

--Sometimes, but not very often; more time than not, the driver tire was not rotating. If I spin the driver side tire, the passenger tire would spin with it in the opposite direction a lot more often; maybe half the time.

I'm confused by your wishy-washy answers.

#1.... Are you saying that it will rotate a full rotation? If it's just rotating like 30 degrees before hitting a "stop", then that is normal. It's just taking up the slop inside the disconnect and differential. If it is spinning full rotations, does it seem to catch at the same point in the rotation each time?

#2.... Normal sounding.

#3.... As with #1, if you're just moving the tire small increments, the driver side probably won't move. You have to actively spin the tire in order to confirm that the driver's side tire spins (and it should spin in the reverse direction as the passenger tire). I can't fathom why it would be different based on spinning the driver tire vs. the passenger tire.

The reason Donny thinks you've broken your splines is because the way you're describing it, it sounds like something is catching here and there, but overall allowing it to spin. I seriously doubt you stripped the spines off the intermediate shaft though... although it's possible I guess.

Can you confirm to me that you were attempting to spin the passenger tire a few times in all 3 steps? Or were you just moving the tire an inch or so each way?

You may need to take a video so we can "look over your shoulder".

[Bay Wolf]

Thanks for the continued follow-ups. When we get back from CO, I'll go back over everything again and reply to James's questions.

[Bay Wolf]

I'm back at this now, and after closer inspection, I only needed a new outer seal and the 3 washers. The bearings looked good to me. They all rolled smoothly; only some discoloration from sitting in grease for 199,000 miles. fishsticks says to reuse the fork, so I will until it breaks.

I'm going to rebuild the original one and send the ATP one back to Amazon. It didn't fix the problem, the case halves are not lined up properly, they were beat up right out of the box, and the actuator didn't bolt on as smoothly as I think it should have. I'm not paying $300+ to be unsatisfied.

EDIT: ATP also used the a different seal on the outer case half. The one they used does not have the protruding lip; it's flush across the air side of the seal.

[Bay Wolf]

Two weeks after ordering, my $13 worth of parts came in today from GMPartsDirect. You'd think for the $14 S+H, they could spring for more than a re-gifted Axe Shower Gel box to send it in. I'll rebuild the old one later tonight.

[Bay Wolf]

When we get back from CO, I'll go back over everything again and reply to James's questions.

I don't think this is necessary now. After reinstalling my rebuilt disconnect, 4HI has engaged fully and held in multiple tests (I haven't tried 4LO yet). I can feel the power in the front axle and it binds as expected in turns on asphalt. All I did to the OEM disconnect was replace the outer seal and the 3 washers and pack it full of Mobil 1 grease.

Thanks to all those who helped me diagnose and fix this thing.