56 not downshifting and slipping

[thessler]

Hi
I have a 56 when it shifts from 2 to 3rd if I'm on the gas it will slip bad. So I go nice and easy untill it's in 3rd once in 3rd you can't make it slip. Which brings up the next problem , down shift rod does not work. This could be related I don't know. If I'm cruising along and floor it the transmission will not kick down, or down shift.
I just went through the procedure of adjusting the down shift rod or throttle control rod , whatever they call it . Mine was way off and after the propper set up it made absolutely no difference in the slipping or the downshifting.
Any thoughts greatly appreciated.
Thanks, Tom

 

[zeroroadkill]

Doug posted this to me!

 

[thessler]

Thanks but that's the procedure is just went through no improvement.
Tom

 

[doug7740]

An automatic transmission that is slipping upon initial and/or hard acceleration will typically indicate the clutch pack is worn out so to speak. What happens is over time the individual discs making up the clutch pack de-laminate. Eventually all shift functions will be lost. The only solution is to rebuild the transmission, preferably before additional de-lamination occurs and the valve body becomes a total mess from particles from the de-lamination.

The only other thing that you can try before rebuilding the transmission is to adjust the bands. I don't think it will correct your slipping problem, but it's worth a try. The reason I say this is if you look at the attached band and clutch application chart you will see that in high gear neither band is being applied. With that said, band adjustments for that particular transmission were recommended at 15,000 mile intervals.

So here is the band adjusting procedure:

(See attached band adjustment points)

FRONT BAND ADJUSTMENT

1. With the transmission oil pan removed, back off the adjusting screw lock nut and adjusting screw far enough to insert a ¼” wide metal block in between the servo piston rod and the adjusting screw.
2. Turn the screw until it contacts the metal block. Then tighten screw a little more too about 10 inch pounds and back off one turn.
3. While holding the adjustment screw in position, tighten the lock nut down to 20-25 foot pounds.

REAR BAND ADJUSTMENT

1. Loosen the lock nut and tighten the adjusting screw to 10 foot pounds.
2. Back of the adjusting screw 1 ½ turns and tighten the lock nut to a torque of 35-40 foot pounds.

doug7740
1955 Thunderbird Blue

 

[thessler]

Doug
Thank you for a great response. Would you know if this adjustment or worn clutch pack would account for the kick down gear not working ? I have followed the throttle rod adjustment instructions to the T, and I can hold it to the floor four barrels open and it won't kick down. Not trying to beat up the car or make it a hot rod but when something doesn't work I'm on it until it does. I'm guessing I can't change the clutch pack in the car ??
I have removed the engine and transmission twice to fix front transmission leaks and rear main seal leak. Three times would be depressing!
Thanks, Tom

 

[doug7740]

I do not think that adjusting the bands would have any effect on the kick down gear not working, unless it was slipping when downshifting into second or first gears. Instead of concentrating on the transmission not downshifting, I would be more concerned with when the transmission shifts from second to third, when you are on the gas, it will slip badly.

doug7740
1955 Thunderbird Blue

 

[CSPIDY]

Have you made sure the transmission is serviced properly?