intermittent non-shifting problem

[FiveOhSlow]

I don't know too much about transmissions, so I'll describe the problem the best I can:


I have a 3000 stall converter, and I was told by the previous owner that it is a non-lockup converter. Twice now, the transmission has not up shifted normally. It will rev like it is in neutral up to about 3000, then start moving forward. It will move a little bit under 3K, but not like it usually does. Unless I hammer it and take it to redline, it won't upshift. It did this a few months ago, and then on the way to the tranny shop it shifted fine. They checked the TV cable and govenor spring, they were fine.

A few days ago it started doing it again, knowing it went away the last time, I've tried driving it 2-3 times, and it kept acting funky. tonight on my way back from the drive, it started shifting normally again. I didn't have time to keep driving and see if it was back to normal.

Tranny is a stock rebuid with about 13K miles on it, no smoke, started leaking a bit just about the time it had this problem the 1st time (unk if related). fluid level has been good on all these drives.

any clue as to what is going on is appreciated.

 

[BlackMetal]

Well if you have a 3000 stall converter, your car is SUPPOSED to stay still until 3000rpm to spool up the turbo. If you plan to drive the car on the street a lot and don't like having to do that, then you should switch back to a converter with a lower stall speed.

 

[FiveOhSlow]

Before, at very light throttle the car would cruise below 3K rpm. And it should be able to shift below redline. Something isnt right, the car is barely driveable.

 

[77 cruiser]

Possibly a sticking TV debris in it maybe.

 

[FiveOhSlow]

How can I check that?

 

[mark_123456]

I just want to chime in as I used to think the same as Turbo6Chicago.
But I discovered that if you have a good converter, even at a higher stall, at low throttle openings (i.e. normal driving) the car should feel about the same as a stock converter.

I have an 9.5" 3200 stall converter, and it feels tight, almost like the stock D5, right off idle. When I press down the gas is when it begins to show its true colors. It flares up and gets my turbo spooled pronto. I drive the car all the time with no problems.

In summary: a good converter does not have to go to the stall speed before the car even moves, by that theory my car would never cruise below 3200, and that is not the case. I can keep the car under 3200 rpm all day if I want to.

It sounds like you have a bad converter or trans.

 

[Blazer406]

Mark 123456 has valid points...... you shouldn't need to go 3000 RPM before it starts pulling. It sounds like a pump pressure problem to me..... maybe some stuck vanes in the pump? A pressure test to see what the pressures were when this happened and when it was shifting normally would be where I would start.

 

[FiveOhSlow]

I've taken it out twice since this post, and it has shifted perfectly.

Mark, my converter sound similar to yours (when its working properly).

Will the mechanic be able to find a pump pressure problem if it is currently working fine?

 

[EricB]

It's not in the T.V cable this is only for line pressure. You stated that it started leaking about the time is started acting up could be that the front pump is coming apart or convertor and is sending filings in to the shuttle vavles. Try pulling it to low gear and if it pulls off like it should or feels like it went to low gear pull the pan a look for metal and if you find metal in the pan pull the trans and replace the pump and convertor and clean the VB.