Topic: Help me diagnose driveline noise

[hilux-1983]

With no noise w/d-shaft out, and quieter w/new u-joints back in, I would say it has to be something in the rear axle.  Could be the pinion bearing, could also be axle bearings and the noise is traveling tup the d-line and being amplified by the transmission.

Before tearing into the third, put the rear up on stands and see if you can hear the noise.  Or get an automotive stethoscope and listen to the pinion as you have someone else spin the tire.

With all of this said. I may have missed it somewhere in the thread but I'll ask anyway. Have you drained the diff to see if you have an excessive amount of metal sparklies? This may turn into a wait and see game. Just be prepared for the worst. Start putting away the $$$$.

[83MT [OP]]

Well...what's excessive? 

Yes there are shavings, but no chunks. Heck there are quite a few shavings in my brand new tranny every time I've changed the oil, but I'm guessing that's break-in, and my rear diff is definitely not still breaking in. I've replaced about everything on this truck, but the front diff, t-case and rear diff are still original, so it woudn't surprise me if they were the next things to go.

[hilux-1983]

I think you'll have different opinions on whats "excessive"  Wait and see game now. I know exactly the you feel. From bumper to bumper there isn't many other things I haven't replaced. It's my DD and it can't be broke down.

[David]

"With no noise w/d-shaft out, and quieter w/new u-joints back in, I would say it has to be something in the rear axle."

I'm certainly not an expert but...if the noise went away without the driveline in place then with one new u-joint the noise decreased I'd be looking at the u-joint NOT replaced. Even when they look good and feel ok they can be bad. I always replace both joints if one goes bad, just good policy in my opinion. I've had shops tell me my u-joints were good to go when in fact they were bad.
I now replace them myself, easy to do with minimal tools. Just recently replaced both rear joints, one was obviously bad and the other could only be seen as bad once removed, lost a couple of needle bearings.
Mines an 83' SR5 short bed.

[hilux-1983]

New u-joint did not solve the problem. It's quieter now, but not gone. So I guess I'm looking at...pinion bearing (both t-case and rear diff?) and what else? Wouldn't be brakes or anything since I didn't hear it in front wheel drive, right?

David, your right. I didn't notice that he was using the singular form of u-joint. Heck whats another few bucks. Change the other one too. It's a lot cheaper than dropping the 3rd.

[<James>]

Next time u have the rear end jacked up wiggle the rear tires to see if there is some slight play in them, when i first got my truck i had a bad vibration somewhere in the rear end similar to what your describing.  when i sasd and did duals i had a new rear driveline made with all new u-joints, the vibration was still there. so when i did 5.29s i put the pinion bearing in there thinking that would help, it didn't.  So one night i had was messing around with my tires and in noticed a Little play in the wheel.  My rear wheel bearings were going out and that was causing the vibration.  I would have never thought guessed that.

[83MT [OP]]

Alright, thanks everyone. No vibration associated with my noise, so I'm thinking it's not wheel bearings. Hm..I guess I should have just had him replace both joints, but I figured he knew what he was doing. I'll do the other u-joint, and if that doesn't do it...I may just wait until whatever it is goes out, and replace it then. I don't have any trips coming up where I'll be the one driving, so I'd probably be ok taking that approach. Thanks a lot for all the help!

[hilux-1983]

Most excellent!! Install that other joint and keep us posted.

[83MT [OP]]

Ok so most likely my noise issue is the rear diff (or the t-case...), and I found one for just the cost of shipping. I'll install it either this weekend or next, and just have one question. This part should be straight, right? The one on the other side is straight. I'm 99% sure it needs to be moved over a bit but just want to make absolutely sure.

[83MT [OP]]

Oook, in case anyone's interested. I replaced the rear diff. No change in the noise. There is some play (up & down) at the t-case/rear driveshaft.

So I'm thinking one of the rear output shaft bearings. Anyone have experience with this? My issue is this: the first main bearing there costs $40 from Toyota. The next major one in costs $60. If I replace both of those, I'm in a bit over $100 with gaskets. The minor t-case rebuild kit from   is $184. So if I'm going to replace more than one bearing, I'm just going to rebuild the whole thing.

If I just pull off the rear two covers and look at the bearings, will it be obvious if they're bad? I'd rather just spend $40 and replace one bearing, and not have to drop the whole case and rebuild it, unless it needs it.

The noise is still getting progressively worse. It doesn't happen all the time, but more often that not now I hear it, whether I'm accelerating or not.

[hilux-1983]

I was reading over this again to see if we ALL might have missed something. I didn't see if anyone had asked if the driveline is phased or not. Lets see a pic of the whole d-shaft. Here's hoping again.....

[83MT [OP]]

Ought to be in phase...I had a driveline shop do the u-joint, and I've had no vibration. Zerks are even facing the same way for me so it's easy to lube. I'll take a photo, though.

There is up & down movement where it bolts to the t-case...

Any one know if I'll necessarily be able to tell if the bearings are bad just by looking at them?

[83MT [OP]]