TH400 - when is it supposed to shift gears
 

hi there,

My car seems to be running just fine. You can allmost not even feel it shift gears, thats how smooth the ride is. Only when I open up the throttle a lot you can feel it shift from 2nd to 3rd gear.

Now usually it will change from 1st to 2nd pretty fast...anywhere between 6 to 12 mph....and then it will change from 2nd to 3rd at about 20 to 25 mph.

is this normal for a TH400 with 1:4.1 gear ratio?

I recently connected a TACH and it shows about 3000rpm at 55 mph...

also I have never ever been able to let the tranny downshift when I hit the throttle hard.

Re: TH400 - when is it supposed to shift gears
 

Hi
1st to 2nd is a quick shift to get you going
not sure on the shift points but the carb has a tab on the side of it to keep the 4 barrels from kicking in before it warmed up.this is a first mod when i get one(bend out of the way)
the kick down cable controls the downshifting.....need a pic or two the pass side of the carb and from the throttle cable drivers side to the back

Re: TH400 - when is it supposed to shift gears
 

he John,
what does the first thing do? can it be adjusted?

and I think my downshift is not connected:
https://lh3.googleusercontent.com/_i...0/P1140393.JPG

Re: TH400 - when is it supposed to shift gears
 

1st pic (not mine)the first thing keeps the secondarys from kicking in while the carb/engine is cold
they last longer lol
the other cable i don't usally see it with the pull chain?
can i see the other end
normally i've seen the cable type i have
it just normally runs straight threw under the throttle not off to the side like my Holley makes it
(i have the bracket to fix it now)
and i have a little extra extention shiney bit you don't need
i have two rochesters it the garage the that mount is different on both
the idea is wide open moves the chain ,moves the cable,downshifts
so see if the cable reaches the end at wide open /if the cable moves along
may need to unhook it to see how far it can go,to feel the shift

Re: TH400 - when is it supposed to shift gears
 

I did some research last night.

little throttle:
1-2: 10 mph
2-3: 20 mph

half throttle:
1-2: 15 mph
2-3: 25 mph

full throttle
1-2: 20 mph
2-3: 30 mph

is that OK?

it does seem that the amount of throttle is influencing the shiftpoint...

@John: the cable you are referring to is connected to my cruise control...not any kickdown device

Re: TH400 - when is it supposed to shift gears
 

TH400 does not have a kick down cable. It's electrically activated. There is an electric terminal on the drivers side of the tranny with a wire connected to it that runs up through the fire wall to a kick down switch mounted on the throttle bracket. then the wire goes over to your fuse block for power.

Re: TH400 - when is it supposed to shift gears
 

that explains that cable replaced with a pull chain
the cruises i have are rod driven not chain does it work?
after the chain is it a rubber diaphram?
and i duno about the shift points

Re: TH400 - when is it supposed to shift gears
 

yes, it goes to a diaphram..and it does not work. I think electrical issue, but havent found it yet!