question about 727

[V-Code]

Hey Folks

trying to get some ideas on what this transmission is doing.

when cold or even just below operating temp. the car pushes against the brake when in drive at a stop sign. almost like one of the clutches is not engaging. brings the idle down to ... gee... sub 200... the car most of the time continues to run but occasionally it will stall. once the car is fully warmed up. stopping at a stop sign is not so much trouble. car will run better, but still feels like its pushing against the brakes and the idle drops a fair bit.

any ideas?

 

[black64]

Might be the Convertor locking up at lower rpm?

 

[Greg Ducato]

Could be a broken or slipping converter sprag but that will drag it down at all temps, not just when cold

 

[Photon440]

What happens when starting out? If you start the car and put it in neutral, is the idle normal? Does it drop just the expected amount when engaging drive while still stopped? Does this 'brake effect' happen only when slowing down to a stop, but isn't there when first starting?

If so, it could point to the front clutch not fully releasing when the second gear band applied while slowing down. Perhaps there's a blocked passage or restriction, and the fluid is released too slowly, something that would be made worse by thicker fluid when still cold.

What happens if you drop the transmission back to neutral when it's doing this trick? Is the 1-2 and 2-3 shift normal? Let us know if you can supply any more clues about this behaviour.

-=Photon440=-

 

[V-Code]

Car idles normal in park and neutral I understand what you mean about releasing from second but even when just putting the car into drive from park the idle drops heavy.

theres times when its on the colder side (say first stopsign) that you will need to put into neutral to keep the car running. back into D and it begins again

let me try a 1-2-3 scenario today avoiding drive to see what it does.

 

[V-Code]

ok so car does it in 1st, or drive. almost like its a super low stall but thats not the case. it is a high stall that was put into the car some time ago. also noticing a fair bit of slip i think as im off by about 5-700 RPM cruising on the highways .. so not the best in fuel consumption. rebuild time for the torque converter?

 

[67 coronet]

it sure sounds like a converter problem,trans internals shouldnt even get a chance to cause a problem until the converter enguages.
fluid level is good,not overfull?

 

[snakeoil24]

You can't lock up a converter that does not lock up.

 

[Greg Ducato]

Sounding more and more like a broken converter sprag

 

[V-Code]

hmm interesting. seems to be quite the part this "sprag" can cause all kind of symptoms from no stall to no multiplier. im assuming from all the information i can find it like a bearing for the impellers? is this a fixable element? or just a new converter?

 

[Greg Ducato]

The sprag is an element of the stator and locks in one direction and freewheels in another. Generally when it fails it will contibute a bit of metal to the system , if caught early it will not ruin the trans or the complete converter.

 

[rdrunner474]

What is the condition of the fluid ? A pan drop to inspect whats going on inside the trans would be my first move . If loaded with metal it ain't gonna fix it self.

 

[V-Code]

on, thanks for the info so far. trans has been like this for almost 20 years and has about 4k miles on it and they are not the easiest of miles as it is a super fun car to drive (its the 71 cuda listed below. 4:10 super track pack car)

 

[Hemi Rebel]

If something in the converter failed the car isn't gonna move at all. Or its gonna shake so bad you wouldnt be able to drive it. Like rdrunner474 asks, what does the fluid look and smell like? When was the last time it was serviced? I dont feel its a trans issue, but that means squat since i have never seen or experienced the issue. Cold engines tend to idle lower or sometimes need to have the throttle feathered just to keep them running, especially if the choke is not working or not existent. And if its not getting the right air/fuel mix and running too lean, that will kill the idle. . Not sure how the engine is tuned either, ignition timing can cause some issues too. Getting as much initial timing in it as possible will help cure some of what you describe. Looks like you have had it quite a while, has it had super tune lately?

 

[V-Code]

I hear what your saying hemi rebel. but feathering the gas would only push the car forward. in park or neutral the typical behaviour is fine when its cold to keep the motor running. problem only occurs in drive 1st or 2nd.

I have a buddy with a lift, once i get though the next three weekends of shows ill head over and pull the pan off. fluid from the stick smells fine and is only a bit darker than fresh stuff.

super tune? sounds like a product..... what might this be?