Replaced driveshaft u joints, now leaking output seal

[clandr1]

Hi everyone,
This weekend I replaced my u joints on my driveshaft (they were in good shape upon inspection, but were OEM so I decided to be proactive after 220k miles). After reinstalling the driveshaft and driving around the last couple of days, I now have transmission fluid leaking out of the output seal where the driveshaft yoke slips in.

In my mind, there are two possible issues:
1. The seal is old and brittle, and failed during the removal/reinstallation of the driveshaft. Need a new seal installed.
2. When installing the u joints, the last cap I installed which was on the differential side bound up a bit as I was installing it, but eventually went in straight. The new rear u joint didn't seem to rotate as freely as the new front u joint. Is it possible that this is leading to vibration in the driveshaft which is causing the seal to leak? I should not that I'm not sure if this is the issue since I've driven up to 80mph on the highway and have not felt any weird vibrations or indications that something is wrong from a balancing perspective.

Appreciate any input/advice I can get. At this point I'm not sure if I need to start by installing a new rear u-joint, or install a new seal where the yoke slips in.

 

[PNWYukon]

Since you suspect the seal, all you can do is remove your driveshaft and check the seal. A new Timken seal is only around $20. If it was not leaking before you removed the driveshaft, then what else could have caused the leak?

The u-joint should be free to move, not bound up, but if you were going 80mph with no vibration issues, and also try at 10-20 mph too, then that should be fine. Did you use Dana or Delco u-joints?

 

[clandr1]

Since you suspect the seal, all you can do is remove your driveshaft and check the seal. A new Timken seal is only around $20. If it was not leaking before you removed the driveshaft, then what else could have caused the leak?

The u-joint should be free to move, not bound up, but if you were going 80mph with no vibration issues, and also try at 10-20 mph too, then that should be fine. Did you use Dana or Delco u-joints?

Thanks for the reply, and I agree that the seal is likely just old - I will inspect it later this week or weekend when I have the opportunity (thankfully I don't drive too much). I used Spicer u joints - if they are widely considered garbage please let me know

 

[OR VietVet]

The answer, like @PNWTahoe says, is your #1, replace the old seal that you pulled the yoke past and then pushed the yoke past. Plus, you should also inspect for a groove worn in to the yoke sleeve where the seal rides and anytime you reinstall, even with a new seal, you should use a thin film of grease at the seal sealing edge or on the yoke sleeve itself.

You just learned that not replacing old parts when doing some work in that area can lead to leaks/problems and should be replacing those parts.

 

[clandr1]

The answer, like @PNWTahoe says, is your #1, replace the old seal that you pulled the yoke past and then pushed the yoke past. Plus, you should also inspect for a groove worn in to the yoke sleeve where the seal rides and anytime you reinstall, even with a new seal, you should use a thin film of grease at the seal sealing edge or on the yoke sleeve itself.

You just learned that not replacing old parts when doing some work in that area can lead to leaks/problems and should be replacing those parts.

Thanks for the tip about the grease on the seal/yoke. And yes, while I've done lots of work on this truck, this is the first time I've done anything involving the driveshaft so shame on me for not knowing ahead of time that I should have replaced the seal.

 

[OR VietVet]

Yes, shame on you, LOL! Live and learn. Check for that groove I mentioned. Some seal manufacturers make a seal that is offset a little to give that seal lip another spot on the yoke to seal at.

 

[clandr1]

I replaced the seal this morning with a GM OEM replacement. It was super easy after watching a couple of YouTube videos to get oriented. I've only driven about 2-3 miles but the ATF drops have appeared to stop. I did add a little extra grease to the seal before installing so here's hoping it'll last another 200k (or at least until the transmission finally gives out).

Thanks to everyone who replied to this thread with input!

Here is what I ordered/installed if anyone is curious. Amazon's website says it doesn't fit my truck, but the local GM dealer confirmed the part number using my VIN.

GM Genuine Parts 24232325 Automatic Transmission Rear Output Shaft Seal:
https://www.amazon.com/ACDelco-24232325-Equipment-Automatic-Transmission/dp/B0013FG60E

 

[OR VietVet]

Yep, looks like the right design at least and likely the right application. Good luck.

 

[CTUBS8732]

I replaced the seal this morning with a GM OEM replacement. It was super easy after watching a couple of YouTube videos to get oriented. I've only driven about 2-3 miles but the ATF drops have appeared to stop. I did add a little extra grease to the seal before installing so here's hoping it'll last another 200k (or at least until the transmission finally gives out).

Thanks to everyone who replied to this thread with input!

Here is what I ordered/installed if anyone is curious. Amazon's website says it doesn't fit my truck, but the local GM dealer confirmed the part number using my VIN.

GM Genuine Parts 24232325 Automatic Transmission Rear Output Shaft Seal:
https://www.amazon.com/ACDelco-24232325-Equipment-Automatic-Transmission/dp/B0013FG60E

Is your truck 4WD? I’m looking for the same seal but in the reviews all I see is this is for 2wd. On the gm parts online it has 3 different seals to pick from but none say 4WD only 2wd. Just don’t wanna grab the wrong part when removing/installing . I only have 1 vehicle lol.

 

[MassHoe04]

Thanks for the reply, and I agree that the seal is likely just old - I will inspect it later this week or weekend when I have the opportunity (thankfully I don't drive too much). I used Spicer u joints - if they are widely considered garbage please let me know

Spicer was the U-joint of choice for Jeeps, when I had my Rubicon. The Rubicon was over 190k when it was time to replace them. I new they were the OE joints, because Jeep shafts had plastic injected into the ears on the shaft to help retain the joints. It was still in there and I had to use a torch to melt it out before I could pop the joints out.

After all those miles and 15 years on the road, the joints were dry and squeaky, but still hadn't reached point of failure.

Spicer greaseless joints are an excellent choice on any vehicle. I would buy again, if I need to for my Tahoe.