Lockup 904 trans Questions.

[hotrodbill]

I have a '78 Dip, that I am having trouble with.

I am pretty sure that it has a Lockup 904 trans, and the problem is....it's locked up.
More specifically the Converter is locked up, when you put the car into gear it dies the same as if you were to let out a manual clutch.
(I have 100% eliminated any engine problems causing this condition, I know it's the tranny at this point.)

Now, what I would like to know, is what years did they make this transmission because I would like to find a replacement. I will assume the "lock-up" is hydraulically engaged.....it's not electronic.
And YES, I want to stick with a lockup converter transmission.

I have sourced a '77 model in a junkyard (same body style car), but at $150 and I have to pull it.....I'd rather not be stuck with something thats not a direct replacement. All the other cars are mid '80s or later.

Any help appreciated.

 

[hotrodbill]

Just found this.....

There is no lockup solenoid. The lockup is hydromechanical, not electric. First year for electric lockup was '87, I believe.

So, is it safe to say '85 to '78 would interchange? What about '77? Is there a way to identify a Lockup 904 just looking at it, or by removing the pan?

 

[rmchrgr]

Is there a way to identify a Lockup 904 just looking at it, or by removing the pan?

Other than the PK # on the d/s pan rail, no. What is the PK # on yours?

Why not try to fix it? Did you check your fluid level/condition? I mean if you've gone to the trouble to eliminate everything else...

 

[oldkimmer]

.................Put in a new tork converter.......78 wont have a lu solinoid................kim.............

 

[69Post]

Will not help to identify untill they are pulled, but the lockup input shaft has 26 splines and the non-lockup has 27. The '77 is not likly to be a lockup (per Allpar). '81 and newer had the 2.74 vs 2.45 first gear ratio.
John

 

[rmchrgr]

Forgot to add - if you pull the unit, look at the input shaft. A lockup trans will have the machined tip, splines don't go all the way to the end. See pic below. Lockup is on top.