1966 flexplate

[scotth3886]

Looks like I'm going to have to tear into the tranny chasing that vibration issue I've had since I've had the car.  Noticed yesterday when we pulled the driveshaft again that output shaft was looser than it had been before.  I want to do everything so I don't have to do it again in my lifetime. 

While looking for replacement flexplate, I found this one from B&M. 

https://www.partsgeek.com/gbproducts/AC/13840-03286558.html?utm_source=google&utm_medium=ff&utm_content=UK&utm_campaign=PartsGeek+Google+Base&utm_term=1964-1966+Cadillac+Eldorado+Flex+Plate+B%26M+64-66+Cadillac+Flex+Plate+1965&gclid=CjwKCAjwvuGJBhB1EiwACU1AiVX_EJuyI2eQehrXdjnr2HbgJKMP-tmiZvDC5EZ5O2f69x9WUYbK1RoCO_sQAvD_BwE

I was thinking that 64 was different from 65-67?  Is this one for 64-66 correct?

[savemy67]

Hello Scott,

The output shaft will be loose without the support of he driveshaft yoke.  The apparent looseness of the output shaft would have no influence on the flexplate.  Why do you want to replace the flexplate?

In '64 some Cadillacs got the TH400, while others got the older Hydra-Matic.  One or the other of the respective car lines required a spacer, I forget which, due to an issue with the block and bell housing with the new TH400.

The B&M part looks to be correct, but I would count the teeth on the part that is in your car, and measure the crank bolt spacing, and converter bolt spacing to be sure the B&M part matches.

Respectfully submitted,

Christopher Winter

[scotth3886]

Hello Scott,

The output shaft will be loose without the support of he driveshaft yoke.  The apparent looseness of the output shaft would have no influence on the flexplate.  Why do you want to replace the flexplate?

In '64 some Cadillacs got the TH400, while others got the older Hydra-Matic.  One or the other of the respective car lines required a spacer, I forget which, due to an issue with the block and bell housing with the new TH400.

The B&M part looks to be correct, but I would count the teeth on the part that is in your car, and measure the crank bolt spacing, and converter bolt spacing to be sure the B&M part matches.

Respectfully submitted,

Christopher Winter

Thanks

"The output shaft will be loose without the support of he driveshaft yoke"

Understood, but it seems looser than it used to be.

"The apparent looseness of the output shaft would have no influence on the flexplate.  Why do you want to replace the flexplate?"

Understood, but I want to replace it while we're in there as a few peeps have had to replace flexplates.  Labor is the big cost, not parts.  I don't ever want to have to take it apart again.  Didn't know if the SP converter had any influence on which flexplate had to be used.

I understand that some 64s still had the older superhydramatic. 

[James Landi]

  A data point for whatever it's worth---- I owned a '61 Cadillac and the flex-plate had several broken "ears" at the point of contract with the fly wheel that was a cause for much concern.  A mechanic wielded the split "ears" right in place using the lower inspection port on the bell housing as his point of entry.  Don't know if this would work for you, but at that point in my life, removing the engines and/or tranny was not in the budget.  It fixed the problem.   James

[scotth3886]

  A data point for whatever it's worth---- I owned a '61 Cadillac and the flex-plate had several broken "ears" at the point of contract with the fly wheel that was a cause for much concern.  A mechanic wielded the split "ears" right in place using the lower inspection port on the bell housing as his point of entry.  Don't know if this would work for you, but at that point in my life, removing the engines and/or tranny was not in the budget.  It fixed the problem.   James

Tranny is going to need to come out to get at the bearings in the extension housing so I want to replace anything else that may need it in the future while it's out. 

[savemy67]

Hello Scott,

If you are going to remove the transmission with the idea of fixing anything that might need fixing for the future, I would suggest you rebuild the transmission, and take care of everything transmission related.

If you rebuild the transmission yourself, be aware that not all rebuild kits are created equal, and you may have to purchase additional parts to get all the parts you should have.  You should also have the factory shop manual, and at least one other reference manual like the Automatic Transmission Service Group (ATSG) 3L80/THM400 manual.  You may also have to buy or make some special tools.

If you are going to have a shop rebuild the transmission, look or a shop that has experience with this transmission, and be certain they re-use the switch pitch converter from your car.

Respectfully submitted,

Christopher Winter

[scotth3886]

Hello Scott,

If you are going to remove the transmission with the idea of fixing anything that might need fixing for the future, I would suggest you rebuild the transmission, and take care of everything transmission related.

If you rebuild the transmission yourself, be aware that not all rebuild kits are created equal, and you may have to purchase additional parts to get all the parts you should have.  You should also have the factory shop manual, and at least one other reference manual like the Automatic Transmission Service Group (ATSG) 3L80/THM400 manual.  You may also have to buy or make some special tools.

If you are going to have a shop rebuild the transmission, look or a shop that has experience with this transmission, and be certain they re-use the switch pitch converter from your car.

Respectfully submitted,

Christopher Winter

Yes, of course, complete rebuild so it doesn't have to come out again.  A shop will be doing it as I can't do much here.