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lock-up verses stall torque converter

dodge1972

dodge1972

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I understand the concept of stall converter. How does the lock-up transmission differ from a regular transmission with a factory stall converter. Are the transmission differ or its it just the converter that makes it a lock-up What year was the lock-up transmission introduced into the b-body production?

Thanks
 
If I recall lookup converters were in production
from the 80s.
Most looked up at around 45mph at a cruise.
Used to check them for operation by just
touching brake pedal at that speed.
You could feel it lock&unlock by touching
&letting off brake pedal
 
All torque converters have an approximate stall point, where they transfer power thru them. A lockup converter also has a stall point, but when a specific point is reached hydraulically in the transmission, hydraulic pressure is applied thru the input shaft to "lock up" the torque converter, thus preventing any slippage between the impeller and stator. Since there is no slippage, the effective power transfer ratio is 1:1. Another benefit of a lock up converter is a lower transmission oil temp from less internal friction in the converter. If I remember, lockups became available in the mid '70's. A lock up trans can be identified by a small snout on the tip of the input shaft. The valve body will include a transfer tube, and the smaller bolted on section will include an extra valve and housing on one edge.
 
This is really an excellent response to my question. I found a late model big block transmission, but was not sure how to identify it as a standard or a lock-up unit. It it fair to say the torque converter must match the transmission because the designs are differ. It has a torque converter, but I need to check part number to verify the balance application. Thanks again
 
There was only one big block lockup transmission ('78 400-2) and it failed miserably and was usually replaced with a non-lockup so it's unlikely yours is a lockup.

Any lockup transmission can be identified by the smooth shaft in front of the splines on the input shaft.

727_LU.jpg
 
Well know I have an answer to my question. Thanks Again
 
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