Drilled out 904 Valve body

[Bluescrawler]

I am in the process of rebuilding a 904 (new clutches, deep pan, seals and everything). I also bought a B&M shift improver kit to install.

Well it seems that someone has already been in the case as there is a small drilled out portion of the valve body near one of the check ball valves. I have attached an image of the location. It's the best, actually only, picture I could find of a 904 valve body.

Can anyone tell me why this is like this? Is this some known improvement? and will it interfere at all with and performanc enhancements expected from the new separator plate from B&M?

I definitely appreciate the help, thanks

Joe O

 

[duster340]

looks like the wall you drill out when using the transgo TF2 shiftkit, dont remmeber exact location but it looks like it is in that area.... doesnt the BM shift improver specify that some wall should be driled out?

 

[Bluescrawler]

The one I bought did not include any drilling, although I have seen some that do. I suspect the previous owner did the drilling, but not sure what the gain is.

Joe

 

[fishy68]

I remember installing a few shift kits in the early 80's where I had to drill out this portion. The kit never explained what it did. Just said do it. There were also adjustments that had to be made the the line pressure and throttle valve. Also had to drive in a restrictor in the case.

Since the B&M plate is basically a stock plate with a couple of holes enlarged it should be ok but I can't say for certain. I guess there's only one way to know. Go for it.

 

[Guitar Jones]

Looks to me like it has already been modified for better shifting, take your B&M kit back and get your money back. Service the trans and drive on.