Additive to fix Torqeflite shudder?

[Rusty Muffler]

Id say no. It's hard for us to understand how severe of a vibration you are chasing. I have a 64 with a ball and trunion setup. It had a worrisome vibration at higher speeds that turned out to be too much grease in the boot, most likely all in one side from sitting on a hot day?? All went away....id be pissed if i tore the car apart for nothing.
Also, you mentioned an engine miss...i would track that down if i were you.

I think I made that better by installing larger main jets with the same rods. Has more power too.

 

[CBODY67]

I thought mine wasn't a lockup?

Agreed, it is not a lock-up converter, but the things which make the lock-up smoother also can make the shifting a bit smoother in normal automatics. Which can aso mean a better ATF with better base oils, too.

 

[Rusty Muffler]

Agreed, it is not a lock-up converter, but the things which make the lock-up smoother also can make the shifting a bit smoother in normal automatics. Which can aso mean a better ATF with better base oils, too.

I think I read that THAT additive was not to be used on a non-lockup like mine.

 

[CBODY67]

Your transmission was spec'd for the old Type A atf. The GM Dexron family of atf replaced that spec in about 1968. The modern fluids are much better fluid than the old Type A atf, by a long shot. Better base oils, cleaning additives, anti-wear additives, and such.

To me, the amount of friction modifiers in the modern atf is not that large, as the lock-up torque converter only has one thing to match rotational speed with. In the normal shifting operations, there are items inside the transmission which completely start and stop when a upshift or downshift happens. THAT is a much heavier-duty situation, by comparison.

The existing, "red bottle", Valvoline MaxLife atf also has a bit of seal-swelling additives in it, as is. Which is the orientation of "higher-mileage" or older automatic transmissions needing something like that, due to age.

In the Sannow book on Mopar Police Cars, it mentions that in the earlier 1960s, the CHP got a new maintenance director. One of his "new things" was to standardize the various oils and such they bought, to more-standardize them. So he bought 20W motor oil, for engines and automatic transmissions. With the stipulation that if the car got into a high-speed chase, the car came in for a full engine and transmission oil change. He noted that the TFs had no issue running 20W motor oil, but the Fords and GM 3-speed automatics DID NOT like it. When I read that, I smiled.

LOTS of options!
CBODY67

 

[MAXWEDGECHAR]

When I worked at the dealer in 1969 the PA state police had Plymouths and Fords. When a trooper brought a Plymouth in for service he told me that at 85,000 miles a C-6 had to be rebuilt where a TF kept on going!

 

[Rusty Muffler]

Drive it long enough to heat the wheels/drums up with your hubcaps off.
Carefully feel the centers of the wheels for one hotter to the touch than the others and find out why.

 

[Rusty Muffler]

Drive it long enough to heat the wheels/drums up with your hubcaps off.
Carefully feel the centers of the wheels for one hotter to the touch than the others and find out why.

I was able to do your test today. FYI, the rear drums were just machined and the brake shoes are new but not arced. I've adjusted them to their loosest point and they were reasonably free spinning. I figure I'll just keep putting miles on them to break them in.

I drove around town quite a bit and I could hear the drivers rear brake howling slightly in and out when approaching a stop.

As I said before it would occasionally feel like the drums were out of round and sometimes not. I felt the center nut on the driver's side rear shaft and it was too hot to touch. The drum was hot too but not as hot. The passenger shaft was hot but not as hot meaning I could hold my finger on for a few seconds.

Are the bearing greased or bathed in gear oil?