727 trans kickdown

[Armyvet25]

First, some history, when bought, all 3 gears no problem, kickdown broke(cable style like Lokar) replaced it, and for the life of me can't get more than 1st and second, yes reverse works so not clutches since 3rd and reverse use same.
It's a built trans with a street racer kit(not manual valve).
Question is setting up the kickdown, I've heard full throttle then pull cable with maybe a 1/4" gap at full throttle, but that keeps it in first forever, went the opposite extreme with a 1/4" at rest, this shifts from 1st to second fairly quick, the tighter I go the longer the shift till to extreme. ratio for the cable pull below and up top pretty close.
help setup please.
383/727

 

[roadrunnerh]

Which cable setup are you using now? I can say the actual Lokar kickdown setup has worked well for my 383/727 Scamp.

 

[Armyvet25]

off brand version of the Lokar, same thing it had on it when it was working

 

[Armyvet25]

is the lever for the kick down on the trans engaged at all prior to accelerating?

 

[roadrunnerh]

If you're asking if the lever on trans moves 1:1 with throttle, then no.

 

[Armyvet25]

If you're asking if the lever on trans moves 1:1 with throttle, then no.

no not that, the lever on the trans, is it engaged at all forward at rest, or completely relaxed- at idle, just trying to get an idea when it starts providing pressure

 

[roadrunnerh]

relaxed at idle.

 

[Armyvet25]

hmmmm, that's how mine is with about a 1/4" play before the throttle starts to pull it

 

[Armyvet25]

here's a weird added info, won't manual shift through 3 gears either, will going from first to second still in first, then to D goes to second, shifter linkage good

 

[roadrunnerh]

No expert here, just relaying how mine is setup. I followed the instructions with the kit last summer.

 

[GTXDAN]

With the throttle at idle and the lever on the trans forward against the stop there should be no slack in the cable.

 

[dvw]

Disconnect the cable all together. Drive it around normally, no hard accel. Does it shift into 3rd? If not it's not a throttle pressure cable issue. The lever will move easily until the cam on the throttle shaft starts to move the throttle pressure valve. If it's not the cable adjustment ? Then you need to check line pressure while moving the lever by hand (disconnected from the carb). PSI should be around 50with the lever forward, 90 with the lever all the way back. And also check governor pressure. Roughly 1 psi/mph.
Doug

 

[Geoff 2]

The Chrys KD arrangement was NOT one of their best designs. Too many variables.

 

[lemondana]

It works fine till someone that doesn't know what they are doing fucks with it. I use the factory mechanical linkage modified as needed. Mine always works. No cable **** for me!

 

[Armyvet25]

Disconnect the cable all together. Drive it around normally, no hard accel. Does it shift into 3rd? If not it's not a throttle pressure cable issue. The lever will move easily until the cam on the throttle shaft starts to move the throttle pressure valve. If it's not the cable adjustment ? Then you need to check line pressure while moving the lever by hand (disconnected from the carb). PSI should be around 50with the lever forward, 90 with the lever all the way back. And also check governor pressure. Roughly 1 psi/mph.
Doug

Thanks for the insight, greatly appreciated.
As far as using the cable vs stock linkage, I'd prefer the stock rods but were missing when I got the truck, and not easy to find.

 

[Rebelrouser]

First thing to try is a weak spring to pull the lever on the transmission forward, especially when using a cable type throttle linkage. All the diesel trucks for example with a factory cable linkage had a spring. Second if that does not work, you said the cable broke and the problem started, might have to drop the valve body and look at the throttle valve and see if it is not stuck in the bore, sometimes if you push it too deep it can stick. A pressure gauge hooked to the transmission can help you tell if the throttle valve is messing up. With a gauge hooked up and engine at fast idle, move the throttle valve back and forth, you should see line pressure smoothly go up and down, specs are in a factory manual. If it does not valvebody for sure has issues.

 

[Armyvet25]

First thing to try is a weak spring to pull the lever on the transmission forward, especially when using a cable type throttle linkage. All the diesel trucks for example with a factory cable linkage had a spring. Second if that does not work, you said the cable broke and the problem started, might have to drop the valve body and look at the throttle valve and see if it is not stuck in the bore, sometimes if you push it too deep it can stick. A pressure gauge hooked to the transmission can help you tell if the throttle valve is messing up. With a gauge hooked up and engine at fast idle, move the throttle valve back and forth, you should see line pressure smoothly go up and down, specs are in a factory manual. If it does not valvebody for sure has issues.

Thanks for more info, will try all suggested by everyone. Thanks

 

[Dave6T4]

In all my years of screwing around with various old Mopars, I have only used a cable kickdown once. I put a 360 in my A/C equipped 1988 Dakota. Because of the A/C condenser, I could not move the radiator ahead, so I had to move the motor back, leaving me no room for factory k.d. linkage. After a LOT of trial and error, I finally got it to work. This entailed drilling different cable attachment holes to ensure that carb attachment and k.d. lever attachment points moved in 1:1 ratio. Since the cable pulls the lever back, instead of pushing it back, as rigid linkage does, a light spring should be added to pull the lever back to rest position. If the lever does not fully come back to rest, the transmission may not drop back into LOW range at stop signs, etc., because some residual pressure is captured in the governor circuit.
That 360 in my Dakota was a LOT of fun. Thermoquad and 340 cam, shift kit in the Torqueflight, and factory 2.76 gears. At full throttle, it would kick out of 2nd into DRIVE at almost 100 mph! Light in the a$$, it was scary in the winter. I always had to carry sand bags in the box, for weight.

 

[roadrunnerh]

It works fine till someone that doesn't know what they are doing fucks with it. I use the factory mechanical linkage modified as needed. Mine always works. No cable **** for me!

In my application, I tried like hell to get the factory stock '68 throttle setup and kickdown (3 piece) on my 383/727 Scamp, it wasn't going to happen.

I didn't want to, but had to purchase the Lokar throttle cable and Lokar kickdown and was surprised at the quality, ease of setup, and function. Sorry, but better than stock setup.

Of course, my 68 Road Runner will always remain original! No Lokar on that girl.