See alot of info on removing half shafts, but what about driveshaft. Do you have to pull C-beam, just loosen, or what? Want to do all 6 joints at same time.

 

If you are smart, you will pound in the pinch seam weld and be able to slip the driveshaft out without removing the C beam.

 

Following. But don’t understand what you mean

 

After you undo the ujoints on the driveshaft, you may not be ablle to bring it down. The piece (or pinch weld) of metal needs to be bent about 1/4 inch
so it will drop down. It dos not affect anything.

 

in both cases. did something similar - took a grinder and removed about 1.5" of the pinch weld about 1/8 deep....

here's one of my older post on the subject -




hope this helps -

 

If you grind that area down, then you don't need to unbolt or even loosen the bolts on the cross-beam to remove the driveshaft? Is that right?

Is that pinch weld in your pic one that's already been grinded down?

In all the years here, I've never heard of this before. I've only heard that some people were able to remove the driveshaft without having to unbolt the cross-beam and they didn't say anything of modifying the car, but most seemed to have to remove the cross-beam.

The other nice thing if you don't have to unbolt the cross-beam, is that you don't have to worry about the transmission dropping and thus smashing the distributor cap.

I had thought of having a shop do mine just because of having to remove that cross-beam and also having to try and support the bottom of the transmission to keep it from rocking down.

I need to replace the ujoints on my driveshaft as the ujoint at the transmission has been toast for a while. I found it on my own as I don't think shops every check anything. Also I probably need to replace the transmission tailshaft seal as that area has been leaking on mine for a while. I probably won't tough the copper sleeve part though. With the cross-beam still bolted down, can you still remove that transmission tailshaft seal that the driveshaft yoke goes into?

 

What exactly was the purpose of GM putting a pinch-weld out like that which wouldn't let you be able to just pop the driveshaft out?

Was it a thing where they had no choice because of that pinch-weld needing to be that wide for structural reasons?

Or did they do it because they wanted to force you to have to remove the cross-beam in order to remove the driveshaft?

It seems like to me there must be a reason why that pinch-weld sticks out that far, as I'd guess they would have normally designed that pinch-weld differently to allow you to remove the driveshaft without having to also remove the cross-beam.

And is there any tips on replacing that seal on the transmission tailshaft housing? I've had a bad leak back there, and I'm guessing it's that seal. I do also plan to get some emery cloth to rub down the slip yoke as I've read it can get a groove that can/will cause a leak.

 

From looking at the pictures, I believe that is the parking brake cable or something running under the driveshaft. Does that need to be removed in order to pull the driveshaft? I do plan on grinding that pinch weld so I don't have to mess with the c-beam.

I was looking at getting a grinder wheel that you put in your drill. Don't know how well that will work, but what have others used to grind down that pinch weld? Here's one from Home Depot:

https://www.homedepot.com/p/Lincoln-...H110/202937222




Thanks

 

Do the mufflers have to be removed? Thanks Dan

 

That's a good question. I know you have to remove the catback if you remove the C-beam. But I don't know if the catback has to be removed if you grind down that pinch weld and pull the driveshaft without removing the C-beam. I'd like to find this out too. As I've had a bad ujoint on the driveshaft at the transmission for a while now. It clunks some.

If you grind down that pinchweld, then I'm thinking replacing the ujoints on the driveshaft would be similar as on a 3rd gen Camaro. So I'll probably get some price checks at the shop on doing the ujoints on the driveshaft for the Corvette and for the corresponding year Camaro. As I'd see if they could charge me the price of a 3rd gen Camaro since I'd have them do it without removing the c-beam.

 

You can simply put a crescent wrench on it and bend it away, and after replacement bend it back.

 

Do you bend the pinch weld towards the front of the car, or towards the rear of the car?

Does anyone have pictures of this?

Thanks

 

It will bend towards the drivers side. we are only talking about 1/4 of an inch.

 

Does that parking brake cable or whatever that black cable is running under the driveshaft need to be disconnected in order to remove the driveshaft via the shortcut of grinding that pinch weld? Or is there enough room to pull the driveshaft out while leaving that black cable in place.

I'll be taking it to a shop to see if they'll do the shortcut method. As that should be a lot cheaper and less risk of something getting screwed up. As they want $400 just for labor to replace the driveshaft u-joints via the "book".

 

As others have suggested, just bend that pinch weld as required to gain the clearance you need. It won't take much. I can't comment about the E-brake cable, as I had mine torn down way farther, transmission out, etc.

Regarding the rear seal on the trans, it can be replaced easily enough. But, do check for radial lash that would indicate a worn tailshaft bushing, which is a common cause of a leaking rear seal. The bushing isn't difficult to replace if you have a press -- yank the extension housing, cut the bushing lengthwise down the oil return channel, grab one side next to the cut with a stout pair of needle-nose pliers, twist and pull. Press in a new bushing and seal with a thin coat of sealant around the circumference of the seal, reinstall in the car and put everything back together.

Regarding why GM designed the car such that the pinch weld interferes with driveshaft removal, I can pretty much promise you that they never noticed that it would and that they wouldn't have done anything about it if they had. It's been over 50 years since much, if any, thought or consideration was given to serviceability with respect to most aspects of automotive design. Cost to assemble is paramount. That pinch weld didn't interfere with the assembly of the car. 'Nuff said there.

Regarding U-joints, be sure to use the correct Spicer joints that have no zerk fittings and that have the special anti-corrosion coating on the bearing caps, or galvanic corrosion between the dissimilar metals of the steel caps and the aluminum driveshaft will become a problem.

Live well,

SJW

 

Thanks, I've got the correct Spicer ujoints with no zerk fitting and the special anti-corrosion coating. I had a while back put in a cat-bypass pipe with new catback and reused the aftermarket mufflers. It shouldn't take more than 10 minutes to remove that, especially if they have two or three guys that can hold the mufflers and pull it off as one piece. On the Vette they quoted $400 by the "book", and on say a similar year Camaro it was $125. Which I'm thinking doing this shortcut it should be like $150 plus doing the seal since they have to pull the exhaust. But I'll find out while it's in the shop for something else to see if they'll give me an off the book quote.

I'll ask them about looking for "radial lash". Though I hadn't really planned on having the whole thing tore apart. As I'm just doing this because the ujoint is bad on the driveshaft at the transmission and figured it wouldn't be much extra to also replace that output shaft seal while they were in there. I'm not worried about the leaking as it's leaked there for years.

Also, I'll give them some "fine" emery cloth and have them clean the yoke. As I've read it can get a groove or the back part of the yoke that sits outside the seal can be rough, which could end up leaking or tearing the seal with the new seal. And so it seems people recommend to cleaning the yoke with emery cloth.

 

You can get a pretty good idea about condition of the tailshaft bushing by just grabbing the driveshaft up at the front yoke, and trying to move it side-to-side. If you can see more than a few thousandths of movement, the bushing is worn and will need to be replaced. If the bushing is worn, but not replaced when a new seal is installed, the new seal will likely fail soon thereafter. Best to fix it all properly.

Live well,

SJW

 

Thanks. I'll ask them to check that while it's in for brakes. I'll make sure they are grabbing the yoke as that ujoint there is bad.

 

I hear that often but is that for certain years with auto? I just removed mine on my 87 4+3 with plenty of room. As far as I can tell it wasn't ground on.

Interesting...

 

I can't recall if I did it on my old 85 with the 4+3. But I have done it on my ZF6 90/91/94 cars.

The beam didn't change through the years with a manual. Pretty sure the body with the tub didn't change either. Be interested to see pictures of your car.