700R4 tech ?s ?? Full throttle in over drive??

[Reumster]

OK I have a very well built 700R4, it has full manual valve body, and shift kit, and all the extras, but I still need that downshift kit. But it still only allows you to apply 2/3rds throttle in over drive before it kicks down to thrid and tacks out. Bad news!

So is it possible to fix the tranny to be able to crack the throttle wide open in over drive without it kicking down into third? And how? And will it require pulling the tranny?

[Project1970]

It's quite possible, yes...police-spec 700R4s were set up this way.

Exactly what was different, though, I don't know. If I were you, I'd become good friends with the guys at the dealer parts counter, and have them pull up parts listings for, say, the trannies from a 1991 5.7L Z28 and also a 1991 5.7L B4C Z28. Wherever the B4C deviates from the regular Z28 (I think it involves the TV pressure setup...the deal with the tranny is this, if TV pressure is higher than governor pressure (TV goes high at high throttle, governor pressure goes high at high speed), it shifts down. I think a regular 700R4 doesn't ever build up enough governor pressure in 4th to make it upshift...).

That's just a thought, I'm not certain. If that doesn't work, maybe try a 1991 5.7L Caprice and a 1991 9C1 5.7L Caprice...

[ty1295]

It is possible. Jegs summit sell a sleeve to do just that.

Also GMC syclones and Typhoons also had the same thing factory.

Head over to Jegs.com do a search, should come up.

Jeff

[Longhorn Man]

Jegs will sell you some kind of a Corrvette 4th gear servo....something like that.

[Reumster]

Yes I know the downshift kit from Summit you speak of I mentioned it in my origanal post, it's part # BMM-70237 I'm looking at it right now in Summit. It states

"The kit has a modified valve that allows the tranny to kick down from forth to third only at two-thirds throttle or more,"

That means to me that opps if you give it more than 2 3rds your still screwed only worse because then your going even faster so when it kicks down your rpm will be even higher pop there goes your engine.

[Longhorn Man]

Top speed is almost alway sin drive, not over drive.
Most engines, especially stock ones, just can't tugg enough in O.D.

[Reumster]

Most stock motors may not beable too but mine can. I can't even open the four barrel up in overdrive, I really need to get my speedometer working again.