Transmission moves car on startup

[Tori]

Anyone familiar enough with automatics enough to know what would be the cause for my 904 to move the car upon startup when in park ?
As soon as the car fires, it will move forward until it reaches the play in the parking pal.

Trans works fine for the most part the rest of the time, but the forward movement is very noticeable.

Thoughts ?

 

[oldbee]

You need to recheck your shifter adjustment I think. Sounds like it's a little off.

 

[Tori]

So you think it's in drive partially ? How is that possible when D is two positions away from P ?

 

[oldbee]

Sorry hadn't had my 2nd cup of coffee! This is probably way out there but you could have an line pressure "bleed over" between a wall in the valve body itself. Heard of it happening in GM's. It was called case porosity. What do you mean the trans works good most of the time? That might help with diagnosis.

 

[66chargerpat]

Is it a fresh rebuild ? If so, the clutch plates maybe a little on the tight side.

 

[Tori]

Not "most of the time" - "for the most part" Meaning, it does what it's supposed to do, but sometimes the reverse engagement is delayed or very soft, and sometimes the shifts are very early. Kickdown does not work either (figure this is adjustment related)
So, for the most part it's okay, just not perfect.

 

[Tori]

Is it a fresh rebuild ? If so, the clutch plates maybe a little on the tight side.

No. do not know it's age/condition/rebuild history. Car is new to me.

 

[khryslerkid]

Kickdown does not work either (figure this is adjustment related)

Gotta get the kickdown set properly. If it is not hooked up at all, you are asking for real problems. The leaver has a big part in the pump pressure.

 

[Tori]

Thanks, it's hooked up and on the to-do list. Just haven't come up with a way to adjust it that i felt positive about. I've read several threads and there seems to be several ways to go about it. Rather confusing.

 

[Fran Blacker]

If it's in park does the car move backward? If so I'd check linkage adjustment.

 

[493 Mike]

A fried rear clutch pack will drag causing such trouble.
Mike

 

[Tori]

If it's in park does the car move backward? If so I'd check linkage adjustment.

What do you mean ? Are you asking if i can roll it backward ? Sorry i guess i don't understand the question.

 

[Tori]

A fried rear clutch pack will drag causing such trouble.
Mike

Anyway to diagnose this without tear down ?

 

[Fran Blacker]

What do you mean ? Are you asking if i can roll it backward ? Sorry i guess i don't understand the question.

Anyone familiar enough with automatics enough to know what would be the cause for my 904 to move the car upon startup when in park ?
As soon as the car fires, it will move forward until it reaches the play in the parking pal.

Trans works fine for the most part the rest of the time, but the forward movement is very noticeable.

Thoughts ?

In your first post you said " car moves on start up in park" but didn't say forward or backward.

 

[Tori]

View attachment 496191 View attachment 496188 View attachment 496189 View attachment 496190

.......As soon as the car fires, it will move forward until it reaches the play in the parking pal.........

 

[miller]

Nope. 'Something' is dragging, from being burnt, or the like.
Pull the pan, look at the fluid, and inside the trans. Fluid will probably smell burnt.

 

[Tori]

Nope. 'Something' is dragging, from being burnt, or the like.
Pull the pan, look at the fluid, and inside the trans. Fluid will probably smell burnt.

Just did that last week. Fluid looked great, smelled normal. There was lots of metal bits however in the pan. Small flakes.

 

[Fran Blacker]

Rut-row

 

[Cranky]

How small are the flakes? Do they look like very fine metallic like in paint or much larger?

 

[moparmarks]

My 72 SSP with a 727 has done this for years. Will move forward when starting, most of the time. Have messed with everything with no change.