Hi all, I currently have my 904 out of my car and is in need of a rebuild. What are some upgrades I can use to make it more reliable and stronger then stock? Some parts i got are..
-low gear set
-transgo tf2 kit
I was also thinking about getting this rebuild kit-
Rebuild kit

What else would you add?
Thanks!

What are you doing with it?? And what are you starting with??

I want to refresh mine too and make it stronger....what's to do ? it was behind a 273..now going with a 340

Daniel

I went to collage from 96-98 for automotive technology. One of my teachers was a co-owner of Georand Brothers Transmission in St Lucas Iowa. During the transmission section of class, we all worked at the shop for about a month. A friend of mine and I both built 904's while we were there. Here's what I did.

Dissasembled the 904. I should have left the one way clutch bearings and springs installed but I took them out. The only thing I had to do was put a small chamfer on each end of the roller bearings. The bearings form a wear pattern in the case and if you put them back in a different location they can lock-up. Chamfering the ends eliminated that chance.

After cleaning the case and all the parts I started work on the valve body. I used a Trans-Go TF-2 shift kit. It was easy to install and came with great diffections. While I was in there I replaced the "manual valve". That is the valve that moves when you move the gears selector. The new "manual valve" lets the convertor "fill" in the PARK possition. Normally it only fills in NEUTRAL. I re-used the 3.8 lever but you can install a 4.2 or 5.0 lever for stronger shifts. The 3.8 worked for me just fine.

The guys at the shop said that they have had trouble with brand new clutch discs. They have had some of the clutch material peel right off of the face of the disc. For that reason they said that if the old clutch pack looked good, to re-use it. After replacing all of the seals, the trans was dynoed on the in house dyno.

One thing to be aware of about the TF-2 kit is that it makes a ton of line pressure in REVERSE. So much so that they have seen the small metal extension, that goes between the band and the adjuster, bend from the pressure. Just take it easy in reverse.

I used a 10" Hughes comvertor with a 3500 stall in a 3600 lbs Cordoba. It held up behind that going mid 12's. I have never had a problem with it. Really just a straight forward build.