SkinnyG's 1977 Chevy Silverado

That sucks. Seems to me like that would be an uncommon issue?

Logically, it's something out of balance or not centered. What are the possible causes?

Likely cause #1 - I put something together wrong when I rebuilt the transmission. 

Or #2 - a component, installed properly, failed.

Possibly an out-of-balance driveshaft ruining the rear case bushing, but I would think it would take out the extension housing bushing first - but it did not.

I ordered a rebuild kit, and I'll tackle it over Christmas break.

Cover me boys, I'm going in.

For the life of me i can't find a single thing out of place in this shot.....nuttin'!!! I'd buy  a poster of this....

Dude, is your transmission stand a homemade adapter or something you can exchange for money? 

This is the bushing in the back of the transmission case.

It looks worse in the picture than my old man eyes can see.

Does this look bad? The ring gear that nestles into this feels sloppier than I'd like. I think you can click the pic to biggie-size it.

Eww. That looks like the bushing seized and spun in the case. 

Yeah, that looks very wrong.

You know what would make this truck even cooler? A 4 speed. 

I have a 4L60 on a shelf, but it'll need $1000 worth of parts to make me happy. I'm saving it and a Vortec 350 for the next truck.

Unless you mean a stick - which isn't the way I want to go.

There is no evidence of the bushing spinning in the case.  I'm going to post this up in a more dedicated thread to get more help from people who may not look in here (I mean, I don't read -every- thread here either...).

Noise: Auto Trans - bushing help?

Am I seeing things, or has that bushing not walked halfway out? 

You're seeing things.  The bushing is exactly where it is supposed to be: "just" inside the far end, such that the rear Torrington bearing shoulder does not touch it. It just also happens to be a deep bore.

I pressed the bushing out, there is no evidence that this bushing moved at all.

There is, however, noise inside the rear Torrington bearing.  I may have found the cause.  I flushed it thoroughly with brake cleen and compresed air, but how do I know it isn't trash inside?  I'll take one out of another TH350 I have.

I stripped down the extra short-shaft TH350 and stole the output Torrington bearing.  It spins marginally nicer than my old one after I cleaned it. This extra trans is in -really- good shape inside.  I'll make a note to buy a new bearing if and (probably) when I rebuild it.

The more I thought about it as I lay awake all night, I am reasonably confident the Torrington is at fault.  I'll be putting 'er back together tomorrow-ish.

Trans is going back together with the bearing from the spare trans.

Also removed the B&M DIY drain plug and welded a nut onto the pan.  Should have done that three years ago.

In assembly there was 0.065" end play, spec is 0.010-0.044", with 0.005-0.025" supposed to be ideal (according to The TH350 Book). Luckily I have some extra shims left over from the 12-bolt install, so I shimmed the bearing at the pump to get within spec.  This might have been a contributing factor to the noise.  Or the result.  Who knows.

With any luck, once we get all this "Christmas Festivities" and "Family Obligations" out of the way, it should be going back in tomorrow.

I hope to also take the driveshaft in and have it checked for trueness. Apparently for a time I was a bit too low, and the cab floor rested on the driveshaft itself.

Are your U joint yoke(diff/trans) angles copasetic ? 

Yes.

I assure you, it was disaster bearing destruction metal-on-metal noise with accompanying vibration.

Truck is back together, just adding fluids now....

Fingers crossed!

Well.....

It's marginally different.

Enough that it's almost a "well, that was a waste of time."

I feel better about my failures in the garage when folks like SkinnyG don't get it right the first time either 

New video fished fresh from of the digital stream.

Drove around a wack today, trans is much better, but it's back to the same subtle noise it made back when I took the poly trans mount and tall stack of shims out and went back to factory rubber. Hey, wait a minute.....

... off to watch video in a mirror ...

Also had the driveshaft straightened by Truckworks in Kelowna - it was 0.020" out - which helped reduce a bit of a shimmy vibration in the back.

Thoughts:

Is it possible the death-rattle-bearing-noise-vibration COULD be coming from the torque converter? I can't make it do it at rest, but if the stator Torrington bearing is going south, is it possible between accel and decel the stator is doing a death wobble under coast?

I have no idea, but if you've got a spare you could possibly answer that in a couple hours?

You have a higher stall converter in there now? I wonder if a stock one would change the driving characteristics enough to alter the issue.

I still have the original converter. The cam won't like it, but it might be a good test.

Have I mentioned how much I d-e-t-e-s-t pulling transmissions?

You need an apprentice.

Make him pull the transmission.