Back to work;
Everything that I haven't replaced or refurbished is now rearing its ugly head.
Prior to these problems with the pig I had been helping a friend with his fj60. He had been dealing with an awful noise coming from where he was convinced was in the transmission. Long story short, I helped him rebuild both a transmission and transfer case that he bought off another rig. When it came to the day to do the transmission/transfer swap, we started by removing the driveshafts and noticed that the stake nut on the rear pinion flange had loosened so much so that I could remove it by hand. Turns out that his problem all along was a trashed rear third member. Lessoned learned, start with the simple diagnosis first and then move on from there. Good news for me is that i now have a split case tansfer and a later 4spd transmission for one hell of a deal, and the knowledge on how to rebuild them.
So that story leads into what I've been dealing with on the pig. I've been trying to diagnose a noise that I've been hearing while in 4wd. It's definitely up front and only occurs when going down hill or my foot off the gas. It goes away under load. The noise is hard to describe, definitely mechanical, maybe a light grinding noise?
So here is what I've done so far. Lock the hubs and ran it in 2wd, no noise.
Unlocked the hubs and ran it in 4wd, no noise.
Removed driveshaft, checked pinion angle with transfer case angle, out about 3 degrees. Replaced 4* shims with 6* shims. Pinion angle is now within 1* of transfer case flange angle. Drove it, noise is still there.
Checked the front drive shaft, which was rebuilt with new u-joints a few months ago, slight movement up and down on the yoke. Yes, the driveshaft is in phase. I might take the driveshaft in and let someone take a look.
Knowing that I've never gone through either front or rear differential, I decided to also check there. I bought the needed tools and read up on rebuilding third members. This is definitely not a post on how to rebuild a third member. I did this as an excuse to try and resolve the noise issue and learn something during the process. It's a bitch to do it correctly, and figuring out what is the proper meshing of the pinion and ring gear is like trying to read tea leaves. i used the FSM and gearinstalls.com as a resource for setting things up. Here's a few pics for posterity:
It took at least a dozen attempts for me to get the shimming right, I hope. The front third member had signs that it had been rebuilt before. I decided to move that to the rear diff. Speaking of the rear, here's some pics of it removed:
As much as I can tell, it appears due to the pitting and rust that water, at one time, got in there while it sat. The chipped teeth tell a different story as well. Possibly a loose bolt that rattled free at one time? Everything was intact though when I pulled it.
So now both front and rear third members are rebuilt, as well as new bearings and oil seals installed. I rebuilt the front end awhile back so no need to go through that again.
Did it fix the noise problem you ask? Dunno yet.
I had read about the stake nut on the transfer output front shaft loosening over time, and possibly causing vibration issues. I checked it today. It was definitely loose, so re-torqued and staked the nut. Maybe I'll re-install the driveshaft tomorrow and see if that has remedied the problem. Feel free to offer up suggestions.