Universal Joints: the Tale of my 2013 Thanksgiving

[dfc739]

I replaced my u-joints about two weeks ago to solve a vibration at ~70 mph. The new u-joints did fix it and I had made several trips to the store and had it on the highway a few times since I replaced them. Yesterday morning I hopped in my Trailblazer to make the 200 mile trip back to spend Thanksgiving with the family.

I was on the highway about five minutes when I heard a loud POP under me and started getting massive vibration. I stopped on the side of the highway and had a look: sure enough one of the u-joints threw a bearing cap. Hey, no problem. I'll just pull the rear driveshaft and run it in 4HI so it's essentially a front wheel drive. Then I look behind me and see a line of blue fluid...

View attachment 31487

I sure hope I hit a smurf back there... I check but am disappointed to not find a smurf carcass underneath. No noticeable damage to the transfer case, whew. It looks like the internal seal for the transfer case has been leaking and the seal for the slip yoke has been holding in the liquid gold Auto Trak II.

Now my choices are: fry my transfer case by running it like this (not actually a choice IMHO), stick the rear driveshaft back in and try my luck, or call for a very expensive tow if any towing place is actually open on Thanksgiving. Well, I was an idiot and chose to put the rear driveshaft back in. Yeah, I know I'm an idiot.

Anyway, I'm putting forth my best granny driving skills, ticking off everyone around me, and I get 1/4 mile away from my place and all hell breaks loose. A lobe on the driveshaft breaks. Well !@#$. I get ready to take it off again and hope I can make it home so I set the emergency brake. But wait, what is this? I'm still rolling? Oh yeah, when the driveshaft went, it took out the parking brake cables. So back into 4HI, pull the rear driveshaft, and I finally get home (with a blue trail behind me).

Since I know you're all going to be disappointed without pics:

View attachment 31488

I've already got another driveshaft ready to be picked up. So questions:

Has anyone else had problems with U-joints on these? I know the originals were held in with injection molded plastic. I know I had the clips in these. They were tight, but they were definitely in place.

Is there a way to replace the rear seal for the Auto Trak II fluid in the NP226 without removing and dismantling it? I'm not talking about the seal that goes around the slip yoke- that one is ok. Thanks for reading my rant and any help.

 

[6716]

Bummer.

Do you mean the seal for the rear output shaft? Or the one between the transmission and the transfer case?

 

[dfc739]

Bummer.

Do you mean the seal for the rear output shaft? Or the one between the transmission and the transfer case?

Yes, I think the rear output shaft seal is what I'd want to replace. I found this picture on ORTB and circled the spot where I would expect a seal.

View attachment 31505

Has anyone tried to replace this?

 

[6716]

Not that I'm the last word on the subject ....

The seal is not super difficult to replace. I did the front propeller shaft output seal on mine.

You tube has a couple of videos on it.

If you already have the propeller shaft out of there you are half-way home.

Once you get the shaft out, you pretty much pry out the seal ... I used a flat-bladed screw driver.

The key to getting the new seal back in is to make sure it goes in flat so it actually seals, and without the "special tool" for getting it in there, I used a scrap piece of 2x4 to pound it into place evenly.

I also picked up a suction pistol to I could get the transfer case fluid back in. Plus the seal and the fluid itself.

Here's a dumb note, though:
If the shaft came out on the highway, the "leak" might just be that the shaft was out, not that the seal is bad.

Can somebody with more experience check me on that?