Lock-up vs non lock-up

[SoulSurvivor]

What is the difference between a Lock-up and non lock-up transmission? Which is the preferred and how can I tell which one I have? 1969 Dart with 318 and 904(which I plan to re-use with my 340).

Thanks

 

[rumblefish360]

The lock up torque converter will not slide into place of the non-lock up torque converter and ise a versea.
With tha pan dropped, you'll find an extra tube on the valve body denoteing it a lock up.
The vin# on the side of the tranny should provide a clue I beileve.

If the trans is OE to the car, it is not a lock up.

OH, Non lock up is prefured for racing and general use by most, I have a lock up in my Duster because the engine / tranny are from a '79 year. I prefur this since it can help assist in mileage gains, however minor they are, I'll take the slightest advantage/gain in these area's.

Converters for lockup tranny's are more expensive in general due to low production/useage. MoPar sell's ecno converters. Good for general performance at a very inexpensive price for ethier style.

 

[SoulSurvivor]

Thanks! And super good answer. And yes..I ask because I am buying a torque converter and installing it while I have the engine out of the car. Something around a 2000-2200 stall. It is the original trans(and motor). Non-lock up it is.

 

[fishy68]

The original 69 will be a non-lockup. Lockups didn't appear until the late 70's. You can easily identify a lockup just by looking at the input shaft. The non-lockup has the splines going almost all the way out to the end. The lockup has approx. 1/2" of the end of the input shaft machined down smooth.

 

[rumblefish360]

Good note there fishy. I forgot about the input splines.