How do i tell if i have a lock up or non lock up trans?

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67cudaResto89

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So i just bought a rebuild 904 assuming it was non luckup but i think i may be wrong any specific things to look for tO determine wat it is?
 
..............A lock up will have about the last 1 inch of the input shaft milled down a quater inch and be smooth.........a non l u has splines all the way to the end.....kim......
 
Define lock up.Is this the drag stripe lock up or something different?
 
first lock up was the converter..in 1978....

over drive with lock up converter in 80s
 
70aarcuda said:
http://farm3.static.flickr.com/2446/3940413483_6c7b048fe8.jpg



pic of lock up and non lock up
Click to expand...




I posted your picture so they won't have to click the link.

click
 
Oklacarcollecto said:
Lock up is the later 904 overdrive transmission. It would have been in the mid 80s and newer cars. I don't know the exact year it started.
Click to expand...

70aarcuda said:
first lock up was the converter..in 1978....

over drive with lock up converter in 80s
Click to expand...
Thats what I was thinking it was as far as the converter.What is the benefit of the lock up over the non lock up.I don't mean to high jack but this lock up deal has been on my mind.
 
Thanks Oklac.i thought I knew but it helps to hear it from someone else.
 
...I know "locking up" is an attempt to get a more tru 1:1 drivetrain relationship.

...so what are disadvantages?

I read all sorts of posts about people adamantly specifying a NON- lockup trans during their build.
 
The one and only disadvantage is the clutch in the converter is not capable of withstanding much power without burning up.
Example would be if you were towing a trailer with a lockup trans truck, they highly recommend not using overdrive/lockup in the hills.
There is just not enough friction surface to withstand heavy loads on it.

Did you know that the friction material is only about a half inch or so wide, depending on the converters?
So you have a disk about the same size as a standard clutch inside the converter, but only about a half inch of the outside diameter of it has friction material surfaces.



YY1 said:
...I know "locking up" is an attempt to get a more tru 1:1 drivetrain relationship.

...so what are disadvantages?

I read all sorts of posts about people adamantly specifying a NON- lockup trans during their build.
Click to expand...
 
Pulled a trailer from Ohio to Nevada with a car and household goods on it..plus the back of my truck was full of stuff....used the overdrive.....truck is a 99 dodge 1500 with 110k miles on it...

I think the trans is a little tuffer then people give it credit for...
 
Not only is the friction material face narrow, it is poor quality. They are known for coming apart and ending up in the valve body. If you do use the lock-up trans, look into a new high performance lock-up convertor, just get factory stall for saving fuel. I think Viper in Alabama has them.
 
The lockup converters are the weak link.
Most people use it anyway when pulling, and some get away with it.
Personally, I would only allow lockup when freeway cruising (Which is what it was designed for.)
Heavy throttle, no way.

70aarcuda said:
Pulled a trailer from Ohio to Nevada with a car and household goods on it..plus the back of my truck was full of stuff....used the overdrive.....truck is a 99 dodge 1500 with 110k miles on it...

I think the trans is a little tuffer then people give it credit for...
Click to expand...
 
So since my motor is out and curiousty set in I went out and looked at my tranny and it has the lock up shaft,the converter looks like any other and I think I only unhooked two wires.I know the 318 is a 1975 butI guess I'll check the numbers on the tranny lip to see if I can tell what year it is.BTW I'm putting a 10:1 340 in the car does anyone think this will be a problem?
 
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