well he couldnt pull up to me or in front of me, he didnt leave my paassanger side mirror, pretty good for a lighlty modded 305tpi, until i hit a certain speed, my car hunts gears badly jerking the car viloently, so i had to let off then he passed me, put if i coulda kept pulling hed be done, stupid 700r4 shift points but i have only myself to blame, i bulit the car for light to light, not highway, but i still dominated that mustang on the highway, cant wait for headers

 

Have you changed out your throttle kick down valve ? Sounds like it's tring to go into passing gear,because of the higher RPM's. B&M makes one and there are others also not sure who's ,plus I think there is a way to over-ride the kick down , but you would have to talk to a good (someone that specialize in 700's) for this information.

 

The 350 IROC (GTA, etc) version of the 700R4 would shift into 4th at full throttle. I started with one that would kick into 3rd gear when it saw 3/4 throttle (kick out of 4th) and then, when I had one built with a new core, I got lucky and got one that would shift at full throttle.

I had tried the B&M valve, don't let them fool you. It will still kick out of 4th, it just takes slightly more throttle to do so (if one is at 70%, the other is at 80% or something like that). It is not exactly the fix you're looking for. There are some who will tell you to adjust the kickdown cable. You can trick it this way, but, you will burn up the transmission rather quickly if you decide to try it (it's not worth it).

Have fun!

 

well my shift is adjusted to shift firmer, i adjusted the little think on the t body to do this, to much presuure wont burn up a tranny, its not to much pressure just shifts firm from 1st to second , a firm shift is good, no slipping either that why i want to know why its bieng gay and hunting lik that, if i press the gas further in when its hunting what will happen

 

I would get on the net and contact some of these companies that do the 700 beef-up's and explain what is happening ,and what you can do to fix this problem. I'm sure that most will try to sell you something ,and maybe you will need it ,but there should be some one out there that will give you an idea of what you CAN and CAN'T do. Then you won't have to worry about trans failure because of misinformation. Also too much pressure can be bad for your trans ,as too little. Just an idea and another oppinion...

 

Ok. I didn't say too much pressure. To get it to stay in gear, most try to loosen the kickdown cable to avoid it seeing full throttle. This will reduce line pressure and can allow slipping. That was what I was trying to tell you not to do. And, actually, more pressure equals more heat so taken to an extreme it can be a bad thing. The reason it hunts is because most transmissions are not designed to run full throttle in overdrive. It is a 3 speed with overdrive, not a 4 speed. The reason it hunts is because it is not setup to stay in 4th at full throttle and now that you put gears in the car, you are running out of 3rd gear and need 4th, but you have to lift to stay in it. You can see if anyone is making a kit to correct this, but the B&M valve won't do what you want. I know, I had one.

 

so what i should have done and should do in the future is drive in 3rd gear and upshift manually to 4th when my rpms get up there, and i wasnt in full throttle either by the way, i was possibly 3/4 down and still was pullin away from him. my car shifts not so firm when i beat on it, but firm when i baby it

 

i doubt it will shift into OD 3/4 throttle as well. and if it does,it wouldve done it while u were racing that time,considering u said it was only 3/4 throttle. i dont think theres a TRUE way of making it shift into OD at full throttle,and if there was,i dont think u would really gain much from it. the OD ratio in a 700 is like .7 isnt it? it would allow u to get to your top speed,but u bettet have several miles to wind it out...

 

I agree, I'm not sure you can do it without swapping in a Corvette (350 iroc, etc) valve body. Or changing to a 350 IROC (GTA, etc) transmission. And, they do pull in 4th, not as well, but if it is what you've got, it's what you use.

 

The 700's on IROC's, GTA's and the other 350s DO NOT shift into 4th (OD) at full throttle. Thats why if I get on the highway, mash the gas, I wont get past about 110mph with the engine at redline.
As soon as I let up a bit, the car shift, and begins to climb again. This is true of all f-body 700's. There is a little piece, a screw I think, in the vette that is different. This enables it to stay in 4th.


--Dave

 

if your gona drive it like that more than a few times a trans cooler (10$ from bone yard, mine came off a saab turbo) should be on the list

 

Hmmm. That may be correct then. When I blew up my 700 R4 for the 10th time, I had one built. After all the destruction, my transmission guy got me a new core to start with (too much crap in the other one). He said it was from an IROC. It did shift into 4th at wide open. I guess it could have been a core from something else. The only other thing I can think of would be a police package car for top speed? I'd have to do more research, it's been a while and maybe I've forgotten what I thought I knew. I was sure the 350 cars I'd been in would shift and I seem to remember an article somewhere (long ago) that discussed this as well.

Is your car a 350 car? The 350's were rated to a top speed of 157 mph (give or take) and they would have had to shift to get there as I remember. Just wondering.

The Corvette had a different 4th gear "valvetrain" in the valvebody that made it shift.

 

I just found this info:

"GM also makes a modified upshift valve which it included in police packages and that part # is 8673948 and sells for around $15. This will allow the tranny to shift into OD at full throttle"

Located about 1/2 way down this page:

http://www.thirdgen.org/newdesign/faq/thirdgen.shtml

That makes me think I did wind up with a police transmission core. It is really hard to say though, it's been a while and the parts are long gone.

And, the B&M site says this:

"How can I obtain full throttle and be in high gear with my 700 R4 transmission?
You'll need a Corvette valve body and governor assembly. If you wish to eliminate part throttle 4th gear to 3rd gear kick down, install B&M's TH 700R4 kick down Kit (#70237) which is found on page 54 of the catalog. This allows approximately 85% throttle opening before kick down occurs."

Located here:

http://www.bmracing.com/noflash/tech/trans.html

Maybe it was a Vette/police car thing.

 

I thought they were only rated to about 143 mph, then shut down. I could be wrong. Lord knows Ive never had it up there. But yeah, mine is a 350.

--Dave

 

I remember reading the 157 mph in road and track a long time ago. But I was just looking around the web and am finding them rated to about 145 (give or take 3 to 5 mph). I've been in one at an indicated 150 once.