Boom

You got the car up already and pulled the transmission? I am certifiably impressed. So I have a question? How high did you jack the car and then jackstands (?) at two corners or four corners? One day I need to get into a C6 and am looking for some pointers in how to get it out. If you can do a 727 in a few hours then I could do a C6 in a few hours.
Two corners but I'd like to get the rear off the ground too.

Those that suggest a problem with the rear, she rolls quiet and smooth....
 
You got the car up already and pulled the transmission? I am certifiably impressed. So I have a question? How high did you jack the car and then jackstands (?) at two corners or four corners? One day I need to get into a C6 and am looking for some pointers in how to get it out. If you can do a 727 in a few hours then I could do a C6 in a few hours.
Long extensions, actually called transmission extensions that way you can work at rear not hanging over the fender against the firewall.

I would definitely be looking at the rearend, that is a lot of force to snap that shaft that clean.
 
Long extensions, actually called transmission extensions that way you can work at rear not hanging over the fender against the firewall.

I would definitely be looking at the rearend, that is a lot of force to snap that shaft that clean.

Really? Wouldnt I have felt a sudden jolt or a nose dive? Wouldnt I be hearing noises as she gets pushed around or when she rolled up and down the roll backs?
 
One little broken gear tooth can stop something pretty fast. The blowing apart of components could have knocked it loose immediately. May be worth your time to at least suck some fluid out of the diff, or try to fish a magnet through the check plug and fish around and see if you pick anything up. If your diff oil is clean without metal particles you may be able to rule it out. If particles are found...... take the diff out and check.
 
From what I see in the pic's a good trans man should be able to get you up and going soon. Tail shaft housing, tail shaft, governor, seals, gaskets, fluid and your back in business.
 
From what I see in the pic's a good trans man should be able to get you up and going soon. Tail shaft housing, tail shaft, governor, seals, gaskets, fluid and your back in business.


Thats what Im thinking/hoping. Now, do I pull the trans out of the other one, install the Gear Vendors unit and use the shaft on this trans? I gotta get this one checked out first
 
Thats what Im thinking/hoping. Now, do I pull the trans out of the other one, install the Gear Vendors unit and use the shaft on this trans?
I think you should do this, because I want to hear your review on the Gear Vendors unit. :)

You still have to find out what happen to this one.
 
The GV unit keeps the stock output shaft.
If I was doing a GV I would find a short shaft 727 out of a truck and use their Shorty Kit. It shortens up the overall length of the combined unit by 8 or 10 inches IIRC. Then you will have a spare output shaft and parts for your broken one. Hopefully it didn't tear the sprag out and ruin your case. Check the case carefully for cracks when you tear it down. That thing did not come apart gently.

You didn't recently replace the motor mounts did you? Had a buddy with a 64 B-body that had a tailhousing break just behind the flange from a bad drive line angle caused by new mounts mixed with an original 40 year old sagged trans mount.

What does the rear U-joint look like? Grease in all the cups or evidence of it around whatever is left of the joint?
The pic shows what's left of the output shaft still hanging in the busted housing so it seems a little odd that the drive shaft left unless the joint broke and let it trail out.

Kevin
 
Damn Dave, I've never seen a 727 come apart like that, and I've beaten the hell out of a few of them. I'm glad you guys came out unscathed, but I would like it if you would take a little better care of my car. :D
Good luck on figuring out the cause.
 
I have a guess... the break appears to have a lot of dark metal... this could be the lighting, but if it really is dark it may indicate you had a serious crack for sometime. The brighter metal would be the portion that gave up over the weekend.

If the shaft was hairline cracked, you would have had no way to know anything was in trouble. Oil entering the crack over time would darken the metal until you eventually got the last driveline jolt that cause it to let go. If I'm right, there was nothing you could have done to know any of this was coming, and the original crack may have been there for decades before the metal fatigue caught up with it.
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Once the long piece of tail shaft was spinning unsupported, I think it's obvious that is what did so much damage...

I tend to agree with others here, it would be wise to check the differential after all of this... but I don't have a guess whether or not it was a part of the cause. Unless you find someone with a stock pile of 727 parts, I imagine you will be using a core to mix with this case if keeping the original matters that much... but I would be very careful inspecting the case for internal (hidden) damage.

Sorry you're dealing with this. Glad no one was hurt.
 
I hadn't replaced the engine mounts though they were probably replaced when the engine was rebuilt several years ago.

I don't know where the front U joint is, that and other parts are missing. The back U is still bolted on
 
Once the long piece of tail shaft was spinning unsupported, I think it's obvious that is what did so much damage...

I was thinking that it might have broken as you said. It's supported by a ball bearing just a few inches behind the governor so it would still be supported.

But... That makes me wonder if the housing was cracked or broken and the shaft has been flexing for a while. The housing breaks... it flexes the shaft... the shaft breaks and then all hell breaks loose.

I'm really not thinking that the rear end broke and caused this issue. It is worth checking out to eliminate any possibility and additional damage.

It still just bothers me that the driveshaft broke off at the rear u-joint.
 
I'm glad the rear U broke off things could have been different if it hadn't.
I'm sure it was moving in directions that it wasn't meant to do.
 
I'm going to send this thead over to a friend that I consider to be a guru and see what he has to say about it.
 
I had a tooth come off the ring gear on my big truck rearend (I did not know what it was making noise) it only made noise on a pull or with the engine brake coasting along or just pedaling you could maybe feel it in the gearshift. So yeah I would check rearend, if you have not changed the lube in many years it's a goo time for it. If changed recently the magnet through the fill hole will tell you right away.
 
FYI my buddy who is a Mopar mechanic said check the rear end. He has never seen a 727 go like that in which the rear end wasn't the issue. He said just because it spins/ rolls means nothing. He has seen them free up after locking up.
 
I have a guess... the break appears to have a lot of dark metal... this could be the lighting, but if it really is dark it may indicate you had a serious crack for sometime. The brighter metal would be the portion that gave up over the weekend.

If the shaft was hairline cracked, you would have had no way to know anything was in trouble. Oil entering the crack over time would darken the metal until you eventually got the last driveline jolt that cause it to let go. If I'm right, there was nothing you could have done to know any of this was coming, and the original crack may have been there for decades before the metal fatigue caught up with it.
View attachment 140357

Once the long piece of tail shaft was spinning unsupported, I think it's obvious that is what did so much damage...

I tend to agree with others here, it would be wise to check the differential after all of this... but I don't have a guess whether or not it was a part of the cause. Unless you find someone with a stock pile of 727 parts, I imagine you will be using a core to mix with this case if keeping the original matters that much... but I would be very careful inspecting the case for internal (hidden) damage.

Sorry you're dealing with this. Glad no one was hurt.

This whole issue has been bugging me since it came up - your explanation is the only one that makes really good sense to me. Good sleuthing!
 
Originality does mean something to me . All three cars are numbers matching. This one is the nicest one so I'm hoping the front half can still be used.
 
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