ws6transam

I have two TV plunger sleeves here, that are slightly different from one another. The holes are in slightly different locations, and one of them has a single, oval hole whereas the other has two smaller circular holes. Can anyone help me identify which one will offer the better performance potential?

Mark A Shields

If I'm not mistaken you can't really just choose one for performance, it has to fit right in order for the pressure in your tranny to be correct for a proper shifting tranny.

ws6transam

I think, after looking at these two valves, that they will function the same. All of the holes are in the same position. However,,, I was thinking of doing this: Relocating two of the holes.

There are essentially three pairs of hole locations in this sleeve: one pair at the bottom of the sleeve on the backside of the plunger. There is another set that gets fluid coupled to the first set when the plunger is 3/4 the way up the bore. There is one last set that also gets coupled to the first set when the plunger is 90% up the bore.

I think these hole sets determine the point where the transmission shifts from fourth to third gear. However, I am not sure what the difference is between the mid-set and high set of holes. Does anyone know? What if I eliminated the second set of holes? Would this eliminate the 4th to third downshift? What if I relocated these holes farther up the bore?

Any thoughts?

Mark A Shields

You can't eliminate the 4-3 downshift with the TV cable, you have to order a different valve body. You can't just adjust the cable however you want, there is one way and one way only for it to be adjusted for proper line pressure.

ws6transam

Mark,
Now that I know what I cannot do, what CAN I do?

What are these holes for, and how do they work? I need to know before I rule them out as a possible method for adjustment of the downshift characteristics. After all, the B&M part # 70237, labeled "downshift kit" is a modified plunger sleeve. Summit advertises the valve as allowing downshifts only at 2/3rd throttle or more, for high-speed cruising in overdrive. It looks like a device that is missing the middle holes. I just want to know what these holes are, and why were the hole locations chosen as they are.

I suspect that the holes can be relocated in order to change the percentage of throttle at which downshift occurs. If they cannot be relocated, I need to know WHY NOT

Pro Built Automatics

Once you know which holes are the 4-3 part throttle down shift you can block them with allen screws. The part throttle passages vary between the 700R4's of different models. The 1992 Corvette had them eliminated, therefore no 4-3 downshift at anything above 75-80 mph. If you wanted 3rd gear you have to manually bring the shifter back. If you get a chance to compare the different ones you have you will see they are in different places. If you still want the 4-3 downshift, but one that takes a lot of throttle to get, then you will need to find one that the part throttle holes are the furthest from the roll pin that is used to hold the TV sleeve in place. If you do the allen screw method make sure you grind off any excess that would inhibit valve movement or the sleeve from going in the bore smoothly.

ws6transam

Thanks for the info!

I've ordered a B&M downshift sleeve so that I can examine it. I will probably go the set screw route and relocate the holes in one of my existing sleeves. However, I'll base it on what I learn from looking over the B&M piece.

--Dan