Have a904's changed?

[vanderkwv]

I found a local bone yard that'll sell me a 904 for $150.00 with an exchange. This is good for me as I contemplate long term plans for my 72 Duster 318.

Has the 904 changed over the years? Is that a difference between my 72 and later or earlier years?

Are later models better?

I figure a newer one might show less miles than mine so it might be a better choice.

[John Kunkel]

There were many changes in the A-904 family after '72.
Other than the obvious introduction of the lockup converter in '78, the '76 model year saw the introduction of the A-998 and A-999 which are heavier duty versions of the 904. Both of these units have the wider front clutch drum with 5 clutches and a wider kickdown band. Some later versions had the lower 2.74/1.56 gear set.

[vanderkwv]

So will some of these transmission NOT work for me, or is it desirable to swap to a later year?

How does the lockup converter differ from mine?

[FASTDARTCHESTER]

For performance you don't really want the lockup style. The input shaft has shorter splines in order to accomodate the lockup converter. This is an inherent weakness under higher power/torque applications. And, as John said, the front clutches are wider with 5 plates (which is good, but you can fit 5 rear frictions/plates in a 4 friction/plate front).

Suggestion: buy a trans that is trashed but not destroyed (doesn't have to be the same year as your car), get a genuine service manual for your car, and tear the trans down, learning everything you can. learn how the bands/gears work and it will really help you understand/rebuild a trans. Then post your questions and the guys will give some good input.

That is the approach i took years ago and it really helped me. I build my own trans' now and save $$$!

I built a 904 for my B-body with the 2.74/1.54 gears and other goodies and it really woke the car up from a launch standpoint (I used a 3.55:1 final drive).


Tom

[raymond]

Try to find one manufactured from 1976 onward . They have steel planetary gear carriers instead of aluminium. These are sometimes a weak link if you give it a bit of a workout.

[dewme5]

vander... have you been to a Pick-a-Part. When I was in california 4 years ago.. lived in ventura, pick-a-part sold 3 speed automatics, for $35. I don't know where you are located, but if you are in driving distance of orange county, there is a HUGE pick a part there.

[Charrlie_S]

John,
Is it possible to tell the nonlockup 998-999 trans from the lockup one, while they are still in the car?

[FASTDARTCHESTER]

check the valve body, lockups use a different flavor (there is a tube on the lockup variety). you have to pull the pan and the valve body however.

-not John

[Charrlie_S]

Thanks, didn't think about that, thats easier then pulling the whole trans, at the junk yard (errrr auto recyclers)