I removed the main valve body from my '88 vintage 700R4 transmission, and in so doing, I saw two chrome checkballs roll out. However, in reading my 700R4 transmission overhaul manual, it seems to call for three check *****: Two regular chrome ***** and one labeled "copper flash". What is this checkball? My transmission only seemed to have two! The tranny was a rebuild in which they hotted it up a bit (unknown shift kit) with Corvette servo, and a "heavy duty clutch pack." Beyond that, I dont know that much.

I *do* know that the stuipd thing never quite upshifted or downshifted properly, and when I popped open the transmission, I found the TV spool valve was bottomed out in its bore by a heavy, white spring. THe plunger that the TV detent lever pushes on was pre-loaded with this white spring. Thus, my shifts were always harsh, and when I adjusted the detent at the throttle body according to factory specs, the transmission never upshifted! I think it had to do with this spool valve. I've since replaced that spring so that there is now very little pressure on that spool valve when in the 'at rest' position.

Now its time to put the valve body back on, but I dont know what to do about this third ball, or even what happens when I leave it out. It looks like it was never in there anyway, because I sure as heck cannot find it anywhere!

A little help or a link to additional info would be very much appreciated!

--Daniel Burk

 

That copper flashed ball should be near the TV plunger if I remember right. There is a little mechanism on the outside of the VB that pushes the big copper check ball out of the way when the TV cable is pulled.

 

That copper ball is not in all units and is usually left out. The job of this ball is to seal off a pasage if the cable is disconnected or misadjusted. This forces max TV pressure which causes late shifts (WOT shift points) and hard shifts due to max pressure. This has been known to malfunction and activate even when there isn't a problem so usually builders leave it out.

Was the heavy spring in question between the throttle plunger and the TV valve? I know a lot of people play around in this area since they are going on the assumption that higher pressure=longer life or firmer shifts, etc. This is not the way to go about it.

 

Yes, the heavy white spring was between the plunger and the TV spool valve. I've since replaced it with one from a 1989 IROC valve body. It looks like the copper flash checkball wasnt there in the first place, so I guess I'll just button it up and see what happens. The plunger now sits in an 'at rest' position as determined by a little counter-spring on the bottom of the valve bore.

Thanks for the help!

--Dan