Sorry for the long post, But this has been puzzling me for a very long time.

1983 Toyota pickup, locked front and rear, 5.29s, rebuilt everything.

I'll start off with the noise it's making. At speeds usually over 25-30 it's Just a metal grind noise I hear on acceleration, louder on decel, and it sounds like it's faster spinning with the clutch pushed in. Doesn't matter if it's in neutral and the noise slows down as the drivetrain does

. It started shortly after I bought the truck about 3 years ago. I use to hear a quiet grinding noise on deceleration only. And I had to have my windows down to hear it.

I replaced the 22r and built a 22r/20r hybrid with all the bells and whistles due to blowing the 22r.

Skip forward to last fall , I decided to flat belly it because the precious owner put a 3" body lift on it. And that's when my grinding noise got way louder. ( because the drivetrain is much closer)

To me it sounded like it was coming from the transfer case. . So I got a Marlin rebuilt kit and put a top shift conversion and twin stick kit in. Bolted it all back together and what do you know didn't change anything.

So I ended up swapping in a rebuilt w56, installing an lc engineering pro clutch, heavy flywheel, new throw out bearing and pilot bearing. And of course, no change with my noise..

So I took the drive lines off and ran in in gear and let everything spin, and there was no grinding. I jacked up the rear off the ground and put the driveline on and then I heard it again. To me it still sounded like transfer case but my friend and grandpa where convinced it was in the diff. So I pulled and inspected it,and the Detroit locker didn't seem to have any wear and everything was set up right. ring and pinion looked great, but all the bearings looked shot so I just rebuilt the diff and put new wheel bearings on both sides and just got back from a test drive only to find that it is still doing the exact same thing!

I'm at a loss and need advice on what to try, so any input is appreciated. I'll try to get a video tomorrow!

 

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I've driven with out the front driveline and it doesn't change. I'm thinking the rear housing could be slightly bent. The shafts didn't want to go in very easy. And I read that that can cause locker problems so today I am going to jack up the rear and remove the shafts, then just drive the diff and see if I still hear it.

 

Twice I have had a rear diff cause all kinds of noises that seemed to be everything else but the rear diff. I installed a new U-joint and that was a hard one to find. Like mentioned, I would remove on shaft at a time and try more elemination of parts. Drive line trouble shooting can be a pain. I have put them on jack stands and used a mechanics stethoscope with them in gear and running in the past.

 

I bolted in my friends extra diff and no difference. I've driven with the rear driveline out, and I've driven with the front. It was quieter with the rear out but it was still there.

 

Well I can for sure hear it's coming out of the case, but I've taken it apart 4 times now and can't find anything. And it's not the only Toyota case I've taken apart. So I'm just going duals because I'm sick off messing with it!