Auto tranny help

[gutboybarrelhou]

I added a 2500 stall converter and shift kit, but the car still pulls pretty hard while just sitting at a red light. The converter shouldn't even engage at idle right? I have to stand on the brake harder than I would like to keep the car from going on its own. Any ideas?

I had this problem before I added the stall converter and hoped that the higher stall would fix the problem. No such luck. Any information would be greatly appreciated.

[RightTime]

Check out this thread on convertors.........

http://www.mach1registry.org/forums/...ad.php?t=58154

[gutboybarrelhou]

Originally Posted by RightTime

Check out this thread on convertors.........

http://www.mach1registry.org/forums/...ad.php?t=58154

So am I correct in thinking it is the torque converter?

[Darrin]

That converter will pull at idle. Heck, a properly built 4500 unit will pull at idle. That hasn't got as much to do with stall as you think it does. But don't feel all alone about it, most people have no clue what a converter does.

The real problem is that you bought a converter that may have less stall then the stock one you replaced and is likely less efficient to boot.

Darrin

[Aerowrench]

What's your idle speed in neutral? A high idle could cause that. Keep in mind your fast idle when the engines cold.

Torque converters are multiplying torque anytime the engine is running including neutral and park. Thing is, at idle the revs are so low (along with the converter output) that the brakes should hold the car. Aftermarket converters are more efficient than stock up to it's higher "stall" speed. "Stall" is when a converter no longer multiplies torque. This varies greatly with vehicle weight and flywheel torque (input). That 2500 figure is a ballpark estimate at best.
When a converter is locked up at cruise it's direct drive.

[jv7]

Properly built aftermarket converters will still creep at idle with foot off the brake, they have clutches in them that allow the car to move at any rpm. The converter will flash to the rpm it was set at at wot. I don't think 2500 rpm is less than the stock converter, the stock unit I believe is around 1800. Of course vehicle weight, gears and power will alter the stall of a converter.

[Darrin]

Originally Posted by jv7

Properly built aftermarket converters will still creep at idle with foot off the brake, they have clutches in them that allow the car to move at any rpm. The converter will flash to the rpm it was set at at wot. I don't think 2500 rpm is less than the stock converter, the stock unit I believe is around 1800. Of course vehicle weight, gears and power will alter the stall of a converter.

Please refer to the other thread that was linked above. The specs on stock stall straight from the Ford service DVD rate the stock converter at 2375-2767 rpm. Welcome to the Modular motor world.

I have never personally seen a factory converter stall less than 2500 on a properly running Mach.

Also, the only clutch in the converter is the lockup clutch. A lockup clutch is never, ever, ever applied at all at idle.

I kinda know this stuff just a little

Darrin

[INDY]

Word to the wise, IMHO I would listen to Darrin he really knows whats going on first hand in our trannys and converters.

[shaker03]

With a light brake, at idle , mash the throttle, 2767 rpm is right.

Good luck Darrin trying to tell this to some. Many posts about this.

[Aerowrench]

Originally Posted by Darrin

Please refer to the other thread that was linked above. The specs on stock stall straight from the Ford service DVD rate the stock converter at 2375-2767 rpm. Welcome to the Modular motor world.

I have never personally seen a factory converter stall less than 2500 on a properly running Mach.

Also, the only clutch in the converter is the lockup clutch. A lockup clutch is never, ever, ever applied at all at idle.

I kinda know this stuff just a little

Darrin

Yep, 4.6's don't have the bottom end torque like the 5.0's did.