904 lock up or non lock up, which one to build?

[737jetdr]

Hey everyone, making some changes to my wagon and I need to have a trans built. I have a non lockup 904 and I also have a lockup 904 trans. Which one should I have built? I will be running a mildly built 318 and using it for street driving. Nothing radical. Thanks in advance for the help.

 

[72Dart6pack]

Non lock up. Keep it simple.

 

[SMCARNUT]

Non lockup agree with 72Dart6pack.

 

[AJ/FormS]

Loc-up
It's the same trans with the same features and a little looser TC for the wagon. And the loc-up will drop your Rs a couple to a few hundred on the hiway. Otherwise below about 50 mph you'll never know it's there.
Plus....... the gearing is 2.74-1.54-1.00 versus the 904s 2.45-1.45-1.00. That's 11.8% more advantage to the loc-up, on the start line.....which is the difference between 3.23s and 3.55s. The 1-2 splits are only 3% different, and the 2-3s are only about 4% different. All in all, IMO, the loc-up for you is a good deal.
And best of all, you already own it.

If you're mildly built 318 includes a cam, but does not include more compression, then you will need that 11.8% advantage, just to break even in low-end TM.

 

[Duane]

Hey everyone, making some changes to my wagon and I need to have a trans built. I have a non lockup 904 and I also have a lockup 904 trans. Which one should I have built? I will be running a mildly built 318 and using it for street driving. Nothing radical. Thanks in advance for the help.

I would build the lockup model as a non lockup. Fairly easy if you already have one of each trans.
The lockup models are the strongest model made imho.
Use the pump and input and valve body from the non lockup in the lockup.

 

[MOPAROFFICIAL]

Hey everyone, making some changes to my wagon and I need to have a trans built. I have a non lockup 904 and I also have a lockup 904 trans. Which one should I have built? I will be running a mildly built 318 and using it for street driving. Nothing radical. Thanks in advance for the help.

Earlier lock up?
Stock 2.93-3.23 gears?
I say do the lock up if so, it will give you a little more mileage and you won't hurt it with a mild combo.

 

[MOPAROFFICIAL]

I would build the lockup model as a non lockup. Fairly easy if you already have one of each trans.
The lockup models are the strongest model made imho.
Use the pump and input and valve body from the non lockup in the lockup.

The 998 & 999, Yes.

 

[Jadaharabi]

What year of lockup?
Early ones from the middle 70s are a piece of crap.

 

[Duane]

What year of lockup?
Early ones from the middle 70s are a piece of crap.

Mid to late 80,s are the ones I use. All the best parts inside.
Steel 4 pinion planetaries 5 clutch drum, and bigger roller clutch.
Many other small refinements.

 

[Duane]

What year of lockup?
Early ones from the middle 70s are a piece of crap.

Low gear too.

 

[MOPAROFFICIAL]

Low gear too.

I put 998 front drum in my 904, 2.74 1st or something, it was back in 1997.. but that was a trick I learned , and a fitting like 5-6 clutches in. I remember trial n error with the shimming the drum too thin a washer and it shaved a nice splinter off drum . I broke a few doing Frankenstein builds in my teen years, luckily it was just slants i was into or it could have blown to bits and taken out a foot or leg. Haha
I'd rather build motors and port heads.