Torque converter question
#1
#2
Generally speaking, there is a trade-off between maximum torque multiplication and efficiency—high stall ratio converters tend to be relatively inefficient below the coupling speed, whereas low stall ratio converters tend to provide less possible torque multiplication.
"While torque multiplication increases the torque delivered to the turbine output shaft, it also increases the slippage within the converter, raising the temperature of the fluid and reducing overall efficiency. For this reason, the characteristics of the torque converter must be carefully matched to the torque curve of the power source and the intended application. Changing the blade geometry of the stator and/or turbine will change the torque-stall characteristics, as well as the overall efficiency of the unit. For example, drag racing automatic transmissions often use converters modified to produce high stall speeds to improve off-the-line torque, and to get into the power band of the engine more quickly. Highway vehicles generally use lower stall torque converters to limit heat production, and provide a more firm feeling to the vehicle's characteristics."
For better fuel economy, I would pick the low stall. But, if you tow or need the torque, you need the high stall and a tow package tranny and oil cooler setup.
Last edited by stev; 08-24-2011 at 11:23 PM.
#4
Thanks Stev! That helps quite a bit. After reading the same page you quoted from and the FSM I am going with the low stall converter if it is the culprit. Seems to be more in line with what Chrysler installed from the factory.
But now I also found that it may be the pump gasket that is leaking according to the FSM. Friday will be an interesting day as my friend and I pull this thing and fix the problem. Hope it is simple and easy to find/fix.
But now I also found that it may be the pump gasket that is leaking according to the FSM. Friday will be an interesting day as my friend and I pull this thing and fix the problem. Hope it is simple and easy to find/fix.
#5
Turns out the converter and all front seals are fine. The fluid was coming out of the top vent of the front pump housing behind the converter. Also while getting the thing ready to pull I found that both cooling lines had crimps, one really bad. Talked to a friend whom has been rebuilding trannys for many years and he said that the fluid was getting too hot and coming out of the vent since it could not go through the radiator cooler. This made since as to why on short trips it would loose little to none and on long trips it would loose up to 3/4 of a quart every 20 to 30 miles. Glad I have not been taking this van on a two hour trip for the last 2 1/2 months. Fixed the lines and reinstalled the tranny. If it still leaks I will bypass the radiator cooler with an aftermarket unit. If that does not solve the problem then I will grip grumble and growl and take it to the specialist friend.
#7