I have a question about transmissions and trans kickdown cable adjustment.
I have a 1964 727 in my 56 plymouth. It's been in the car a few years. I have a kickdown cable setup on the car as I didn't have any OEM linkage. I'm having an issue with the trans slipping sometimes. Seems to slip on light throttle upshifts, I drop it into neutral and then back into drive and the trans is fine.
So I was talking to someone about the kickdown cable and reading up on them. I get the car up on the lift and at wide open throttle, my trans lever is all the way back so I think that's where it's supposed to be. Then I read a hot rod article about the lokar kickdown and how some people put a spring on the trans lever to pull it forward and they shouldn't do that. Well I have a cable setup from Mancini, not the lokar setup. The mancini setup comes with a spring to pull the trans lever forward. Then I read about how mis adjustment can wreck your trans. So which way is it supposed to be. Pull the lever forward with a spring or don't pull it forward. It's so confusing.
I've check my trans fluid, it's not burnt and it's full.
I'm thinking I have to have someone take the trans apart to see what's slipping but I want to make sure I didn't cause the problem or that If I did, I don't cause it again.

Any suggestions.
Thanks,
Nick

Not sure if this helps, but I am using the Bouchillon cable kit. It uses a spring to pull the lever forward and the cable to pull it back.
Ideally, the factory setup is the way to go. But if you are like me and have different intake, carb, efi or transmission, a cable is the only solution that has a chance of working.
Craig
https://drive.google.com/drive/folders/0ByFJ9dE-12AVeHhhNUNISExkRUU

The spring pulls the cable assembly taut, that is it's main objective , a side effect is it makes the gas pedal a little harder to push down.

Slipping can be caused by a number of things and what you think is slipping may actually be an RPM flare caused my a timing issue . a stock 727 dances a fine line on shift timing by design , add a shift kit , which changes the line pressure , change clutch pack or band clearance and it throws that timing off.

What gears is your SLIP happening between?

It's not all the time. When it's happened first few were light accelleration at the upshift from 1-2. Once it happened at 2-3. yesterday it happened just pulling off the lawn and out of the driveway. It's definitely slipping...I wind up putting it into neutral and then into drive and then it's fine..and it doesn't happen every time...Right now there's no consistency.

Misadjusted Throttle valve cable will usually smoke the front clutch , 3rd gear. What you have could be a slipping rear clutch ?

History of the trans ? Rebuild last when , how many miles ?

Don't really know. I bought the motor and trans out of a running car (64 Polara) both had been built but I don't remember all the details. I had gone to see the car and hear and drive it. Then the guy pulled it to change to a big block. It was a show car already, not a rat that he was fixing up. That was maybe 6 or 7 years ago and I put the whole thing into my car. I've probably put 15k-20k on it. I don't know for sure as I had years where my odo didn't work. However I have found someone who is an expert with these transmissions. I'm just going to drop it off at his shop and let him go through it and see what he finds..

Does the cable move in unison with the throttle? IOW, does the trans lever start to move rearward as soon as the throttle is opened?

With some of the cable setups there is lost motion due to a mis-match of carb lever travel and trans lever travel.

I will have to double check it. I did look last night and at WOT on the pedal the trans arm is all the way back where it should be. Being that it's a pull cable I'd think if there were slack in the cable to where the trans arm didn't move when the throttle was starting to be depressed. then the trans arm wouldn't reach all the way back and WOT.

I had a problem like that with a buddies 340 Challenger. He changed the intake and went to a Holley carb and over the years the throttle pressure linkage was removed for a manual valve body. He later went back to fully auto trans but it had mis-matched linkage on it. If I adjusted it to be all the way back at full throttle the trans would flare on shifts. When I adjusted the linkage right to move with the throttle as soon as the throttle moved I could get it to have good normal shifts with no flare. But it would bottom out before full throttle and I could not get full throttle with it. I figured with all the wrong linkage the ratio was wrong as when it was adjusted to full throttle it did not move right away with the throttle and would not shift right as it would flare on shifts. I set it to shift right so he could drive it without burning up the trans but he did not have full throttle. I told him to find the correct linkage or we would have to go with an aftermarket cable setup or back to a manual valve body. Ron

That sounds like a shift cable adjustment problem to me?

I assume he's returning the throttle to idle when shifting to Neutral thus reducing the load on the slipping component(s) and allowing them to engage.

Same thing would likely happen by just reducing the throttle.

I would think if it were a shift cable adjustment, it would happen more often, more consistent and begin to slip as soon as I put it into gear? I don't have an issue getting it into any other gear.

The few times it has happened, I have let off the gas and stepped on it again and it slipped again. That was when I went for the button and put it into neutral and then back into drive...

My fear is I have something in the kickdown wrong, I have the aftermarket cable and for sure can't determine if the trans lever should be pulled forward with a spring or not. Depends on whose cable you buy. Also since I did not fabricate any of my own brackets for the kickdown cable and throttle setup. I used stuff from the company I bought the cable for and it was for use with the carb and linkage I'm using.

I'm going to drive it a bit more before I pull the trans out.

The other part of my issue is that winter will be upon us soon here in NJ and if I'm getting it rebuilt I need to get in line for the guy I want to do it. I have quite a few trips planned next year and don't want the transmission to put me out of comission for any part of the driving season.

If you have the flimsy cable like the Lokar, you definitely need a spring to return the lever forward.

The problem with adjusting the cable so that the lever is full back at WOT is that it leaves the rest of the travel in question. A properly configured cable setup will have the trans lever moving in unison with the throttle lever from idle to near WOT.

What's the distance the cable is mounted on the bracket measuring from the throttle-shaft centerline?


Does the engine flare up sometimes while cornering too?

If so then it's simply a low oil situation.
You do check the oil level idling in Neutral right?

I would have to go measure that distance. Never thought to measure anything upon original installation. I just installed per the mfgr instructions.

No, the engine doesn't flare when cornering.

Yes the oil gets checked when warm and idling in neutral..

Having not seen the actual lokar setup. I can't say whether this cable setup is any more or less flimsy than the lokar setup. All I know is I have whatever setup Mancini sells and it's not the lokar one.
I will put the car up and go through the linkage again.

I went with this cable setup so that I didn't have to fabricate my own linkage.

Regardless of your TP setup, your slipping symptoms point to internal leakage i.e. seals/rings.

I'm planning on pulling it out and letting a trans guy go through it.
I'm just searching around for info to be sure I get the linkage adjusted properly the next time if I wound up with it wrong this time (hoping I didn't cause this problem)