Hello everyone, I am hoping for some assistance on this. You will have to excuse my inexperience, but I have always been a little automatic Transmission challenged.

Here is my situation. I transplanted a 351w and 3 speed automatic out of a 78 Tbird into my 64 F100. Originally I just dropped it in and went. I recently rebuilt the motor and upgraded to an 4barrel intake and an Edelbrock Carb. During the installation process I realized that there was a bent rod that went from the carb to a lever on the side of the transmission. Unfortunately, I did not document where that rod attaches exactly, should it be on the top of the throttle lever so it moves back as I give it gas or on the bottom so it moves forward?

On a side note... what the heck does it do? I thought it was part of the kickdown linkage and thought I would just leave it unhooked, my father thinks it controls the amount of pressure goes to the clutches.

I have noticed that since the rebuild it clunks into gear from park. I haven't noticed a difference while driving. The idle is set a little high 800-850 so that may be causing that as well.

Before I go tearing into things I thought I would bounce the issue off some of you folks.

Thanks

 

sorry forgot to add that the transmission is either a C4 or a FMX, through my internet research it turns out that they used both in the 78 TBird. It does have a detachable bell housing and the lever in question is on the left (drivers) side.

 

Is the transmission case aluminum or cast iron? The C4 was aluminum, the FMX was cast iron, both typically had an aluminum bell housing though. Also, the C4 has a square pan with 11 bolts, while the FMX has 13.

 

It is an FMX.... cast iron case

 

That lever is for passing gear, the bent rod should push against the levers spring tension to achieve passing gear. You can leave it disconnected if you want, it just wont have a forced downshift (passing gear).

The modulator controls pressure for the transmission, your dad is remembering the rod for a AOD transmission, it doesn't have a modulator and the line pressure is controlled by the rod or cable.

 

good to know, thanks for the information.

 

The lever in question is your kick down lever for the passing gear as said. The cluck your talking about sounds like a universal joint on the drive shaft. I would tune your new carb in and set idle before you change it that may fix your clunking.

 

FYI:

1977/79 Thunderbirds with 302/351M/351W and 400's could have a: C4 (11 trans pan bolt holes), FMX (14 [not 13] trans pan bolt holes), C6 (17 trans pan bolt holes).

1970's Passenger Cars sold new in CA may/may not have different A/T's than 49 state/Canadian passenger cars. It all depends on the various applications due to CA's strict emissions standards.

 

Thanks for the additional information.

If it doesn't rain this afternoon I may have time to go out and fiddle with it. I have a few other things to do on it as well...

I was thinking it might be a U-joint as well, when we did the engine change we put one new one in, but who knows how old the other 2 are, plus I know they will need some grease.

thanks again.

 

I am sorry but can someone dumb it down for me... What does "forced downshift" or Passing gear mean?

I am trying to decide if I should leave my transmission lingake.

If it's not needed why was it installed then?

 

"Forced downshift" means just that. The lever/rod/cable pulls/pushes a rod on the transmission that forces it to down shift. This is also called the "passing gear" as that's usually when it happens, when you floor it to get around some back marker on a two lane road.

It is not a "passing gear", it's actually just one (or two sometimes) gears lower than what you're running in.

Leave it hooked up and working, as your trans doesn't like high loads at low RPM. Better and easier on things to shift down--not to mention quicker to accelerate.

It is "needed", as the point of having an automatic trans is not having to manually shift.