Ok bear with me on this I might have to type this in installments. I have seen a countless number of postings for "my tranny won't shift into 3rd at WOT" and "how do I get a WOT 4th gear shift." Well I finally got a tech manual after searching E-bay for a year and I would love to help everyone who is as upset at their tranny as I was until I understood.

I am going to keep this simple for my own sake but this will certainly help. Obviously, there is upshift and downshift functions to a 700R-4. What controls these functions. Please keep in mind these explanations are extremely simplified but accurate.

What controls upshifts:

Governor Pressure (Forces upshift)
MTV Upshift Pressure (Used to delay upshifting)
Shift Valve Spring Pressure (Helps force downshifts)


What controls downshifts:

Governor Pressure (Forces upshift)
MTV Downshift Pressure (Used to help force downshifts)
Shift Valve Spring Pressure (Helps force downshifts)
Part Throttle Pressure From TV Sleeve (Helps to force a 4-3 downshift)
Detent Pressure From TV Sleeve (Helps to force a 4-3, , 4-2, or 3-2 downshift)

If your tranny has a properly adjusted TV cable and you can not get a WOT
3-4 upshift then you can start by blocking the part throttle holes in the TV plunger sleeve.

If your tranny has a properly adjusted TV cable and you can not get a WOT 2-3 Upshift you can start by plugging the Detent holes at the rear of the TV Plunger Sleeve.

These two modifications will eliminate 1/2 of the automatic downshifting functions with no damage to your tranny and should give you manual control of upshifting. The only things left to force downshifts at this point are MTV up and down pressures coupled with shift valve spring pressure.

If these mods do not work then you can almost completely eliminate the automatic downshifting by blocking the MTV downshift valve and placing the MTV downshift spring behind the MTV upshift valve. Although, I would first start by backing off the TV cable no more than 1/8". This will only sacrifice about 4% of line pressure and lower MTV upshift and downshift pressures to allow a WOT 2-3 and possibly a WOT 3-4 upshift.

Hope this helps and any tranny guys please feel free to correct any errors.

CamaroMike

 

Hard to believe there are no comments or questions.

 

I found your post very informative. However, I don't understand some of the parts described, let alone I.D. them on a valve body 3 inches in front of my face. Maybe a description of the parts mentioned and/or location on the car/valve body. That would make it much more useful.

 

I know this is an old post, but I'm getting desperate to fix this 2-3 at WOT problem. Can you explain how to plug the holes at the rear of the sleeve? Will plugging these holes sacrifice any pressure needed for clutch application? I upshift manually at 7000. Will this even make a difference for my application or is this particular modification a waste of time for a manually shifted application?
During other searches, I have found posts about removing a checkball capsule. Do you or anyone else know about, and/or have you tried this checkball fix before?
Please post your results!

 

It's gonna be hard to help you as I do not have pictures. But if you want to start at getting your 2-3 WOT shift I would begin by blocking all holes in your TV sleeve. This will in no way damage your transmission, it will just eliminate most downshifts. If that does not work let me know and we can go to step two.

 

What can be safely used to block these holes?

 

I tapped the holes and used JB Weld to hold bolts in the sleeve. Make sure the bolts do not interfere with the plunger. I then cut the bolts down until the sleeve fit into the valve body. Worked great.

 

prolly not as helpful but if you can find a C4 vette 700R4 it has a special valve body that allow WOT shifts.... just my pennies