I pulled the old outdrive last night and found the U-joint bellow full of water. The U-joints have surface rust on them, and the gimbal bearing seems okay, but should be replaced after any exposure to water. I had a mechanic replace the boots for me because I had already pulled the drive twice, and the price was right, but when I inspected the bellow I removed I found damage from a screwdriver being used to pry the edges into place. I am sure that is the cause of the water intrusion, but I went ahead and took sandpaper to all of the mating surfaces, to make sure there are no other areas for entry when I reassemble. U-joints run around $400 a set, I think, and the bearing around $50. You need a specialty tool to remove it that runs $150, but I read about people successfully doing so with a slide hammer, so I grabbed one of those from Amazon for $70 instead. This is another case of if you want something done right, do it yourself.
The U-joints are not the ones that have grease zerks, so they are non-servicable. I have a spare set from the new drive, so I don’t need them, but I was hoping to sell them along with the old drive once I fix it, to get some money back. I’m going to look at cleaning them up, since they still feel okay:
I found bluing from excess heat on the shafts and the input of the upper unit was very difficult to turn. I opted to pull off the bearing carrier and inspect the upper unit, which seems surprisingly easy to turn by hand and in great condition internally. That means the issue is either the bearing carrier or the connection between the two. The bearing carrier spins freely, so this pinpoints the lash that needs to be set on the drive. It’s the shim at part 15 on this diagram that needs to be measured, purchased, and installed:
I found the instructions for measuring it online, but need a special $50 tool to do so (in addition to a micrometer, which I already have).
The drive had a single .003 shim in it, which is what it came to me with. I wonder how long this has been wrong. It says it may need up to five shims, and .003 is the smallest size they come in. This caused excessive heat, noise, and I’m sure wear on the drive. But fortunately it looks like a simple fix compared to what I thought it would be when I pulled the drive and attempted to turn the input shaft by hand. I found a used Volvo P/N 3850600 on Ebay, and placed a bid on it for $20. We’ll see if I get it.