ChevyRacer

I have searched and however the fact is there are mnay thread on making our trannys shift into 4th at WOT.

But what i want to know, is what is the way that is easiest? Which way is cheapest?

I know the tranny can handle it, its brand new with racing components. I just want to be able to shift into 4th at WOT for another gear to get way ahead of people.

But i want a method that allows downshifting as well. I dont want it to be stuck in 4th gear at 40mph....

ChevyRacer

TTT

Z28GEN3

only thing i can say is get a shift kit, the kit im installing allows me to manually shift it into 3rd for passing and 4th if i want OD, but its still a full race automatic.

if your tranny is new with racing components then, "my question is," why wasnt the VB upgraded with the same components to allow you this option. I've only rebuilt my transmission just recently under the watchful eye of a qualified trans tech, i bought the transgo shift kit the good one, so i dont know everything.

ator

I too am wanting to be able to shift into 4th at WOT. I was under the impression that the a stock 700R4 will not go into 4th at WOT but I didn't know that with a shift kit it will??. I have a B&M shift kit installed in an otherwise stock transmission. I have also not tried to go into 4th at WOT. But, I am trapping at 5000 RPM in third and would very much like to be able to hit 4th at about 4500 RPM's.

If anyone else has done anything to do the 3-4 WOT shift I would very much appreciate it to know.

Thanks

robotic_junky

I have a 700R4 with the B4C package, police package, with heavy duty gears. It will shift into 4th. The tranny shifts at 5,000 RPMs in every gear at WOT. I would expect the shift kit to let you do it.

antoine

my 700 did the samething untill i installed the b4c police package upshift valve that you can get from a chevy dealership or gmpartsdirect. part number is#8673948

Supervisor42

This one will let you use 85% throttle in 4th.
http://www.jegs.com/cgi-bin/ncommerc...66&prmenbr=361
Another source says: "recommended for engines under 250 HP."
and why.

ator

Thats not really what I'm looking for. Next time I go to the track I'm just gonna try to shift it from 3 to 4 myself and see what happens. I figure the worst thing that could happen is that it will just stay in 3rd which is what it's been doing anyway.

robotic_junky

Well, buy the valve spring for the B4C package like antoine said.
You have a shift kit, which I would except that it would let you do the 3th to 4th shift, automaticly and manually.

ator

Yea, I figure if it doesn't shift then I'll get that valve spring.

Pro Built Automatics

You can make the 1988 & up 700R4's (the majority of times) do a WOT 3-4 shift, by blocking the 4-3 part throttle passages in the TV plunger sleeve. Thjis requires 2 Allen screws ($.17 each), and a Dremel, to do this.

Thirdgen89GTA

iTrader: (5)

Old thread I know, but how much holding power does a 700r4 have in 4th? Is quick wear n' tear something people will have to worry about?

Also, are 4L60Es subject to the same issues with a WOT 3rd to 4th gear upshift? Or is that something that can be programmed with the PCM?

Reid Fleming

iTrader: (2)

The 4L60E's should make the shift no problem. All the LS1's were doing 160 mph stock with automatics.

That pesky TV sleeve is the culprit with the 700R4's in F-bodies. I can't see it being much of a problem as the Corvettes of the 1980's could make the shift.
----------
That's worse than stock in my opinion. That means that on a stock engine, at 66% throttle it's hovering on making the downshift from 4th to 3rd. This puts you right at red line. On the valve above, if it's downshifting at 86% throttle, that's going to make you downshift and go well past the redline.

You want it to stay in 4th at 100% throttle for safety and top speed reasons.

Supervisor42

The 3-4 section of the 700r4 went thru atleast 3 design changes from '85 to '90. The section of the transmission was originally designed as a true "overdrive". The idea was to be able be able to drop engine rpm at light throttle highway cruise speed to boost MPG. That's the reason that it drops out above 50%. Even like this, the early 3-4 sections burned out in record numbers. Since it was redesigned more than twice, the factory clearly had trouble getting it to work just up to 50%.
The later 700R4 transmissions are better than early ones needless to say and you aren't even safe going by year models. The design changes were by trans serial numbers so 2 different versions could be found in the same year model cars. The 4L60Es are even better because the factory continued to work on the 3-4 problem after '90.
There are some other factors to consider. As the rpm of the engine rises past peak torque, the torque (not hp) declines and the 4th clutch actually stands a better chance of carrying the torque at 5000 rpm than 4000 rpm.
Also, if the trans is driving a 4.11 rear at WOT it will be under much less torque than if it's got 3.08's.

As Pro-Built said, blocking off the ports in the TV sleeve will keep it in 4th at WOT. But, I can't help but wonder what it would do to the other part throttle downshifts.
Excellent point about the 86% downshift. I hadn't thought about that. I bet it would be a rude surprise, just as you're pulling ahead...WAAA, back to third.

Now for the real question we should be asking here:
The torque converter clutch. How much torque will one in a "GOOD" torque converter carry?
I think locking up the TCC in 3rd at WOT would give me all the top end I need, I'm just afraid of roasting a $350 converter...
At 6500 rpm I should be under 300 ftlbs of torque. After lockup at 6000 it should be just above 300.
The stock TCC is only good for about 150 whopping ftlbs and the converter people just won't say what theirs will actually carry...

Thirdgen89GTA

iTrader: (5)

Doesn't your converter lock at about 75mph?

Mine does, this is a semi-stock rebuilt trans I did in a friends garage with some help. Kevlar band, .500 boost valve, vette servo, transgo shift kit, and some stuff I can't remember right now.

Watch the for the lockup shortly after the 2nd to 3rd upshift, the RPM's will recover to about 4000 then stay there but the speedo continues to climb from 80mph to 100mph before the tach starts to move again. You can hear engine RPM drop as the converter locks up.

BTW, if you time the 0-60 it only took 5.01 seconds. I miss that engine. Dead stock idle.

http://media.putfile.com/zero-2-115

Supervisor42

You can definately hear the RPM drop. Is that the 4L60E or the 700R4 in your video?
If it's the 700R4, what year ECM is in it?

v10viper04

So what i got out of this is you cannot buy a kit that allows for the WOT 3-4 shift then be able to have the tranny downshift when your slowin down? or is there a kit or part out there that will allow the 3-4 WOT shift and tranny will still work properly? All i read is that a shift kit will make the tranny work fine with the 3-4 WOT shift. True or not?

Thirdgen89GTA

iTrader: (5)

Thats the 700r4 I rebuilt in a garage. Never quite figured out what the little hiccup is on the 2-3 WOT upshift. However the trans still engaged firmly so I wasn't worried considering it was a shade tree mechanic effort and I didn't have any experience rebuilding a transmission. I was however too poor to afford to have one built for me. I spent about $260 on the rebuild including the shift kit, vette servo, and .500 boost valve.

Trans is long sold to someone else who I'm told has it behind a bottom 12 second car. Never expected it to hold up to that, I figured 12's with traction and it would probably fail.\

Currently the drivetrain is a 95 LT1/4L60E out of a 95 Buick Roadmaster with 55k. I have aluminum f-body heads on the side, I just haven't gotten around to getting them worked. I also haven't driven the car in 2 years its in storage right now with the swap unfinished, real life got in the way.

Pro Built Automatics

You can make the 1988 & up 700R4's (the majority of times) do a WOT 3-4 shift, by blocking the 4-3 part throttle passages in the TV plunger sleeve. This will affect the 3-4 upshift only, nothing else.

Reid Fleming

iTrader: (2)

The modified plunger sleeve does everything you want it to. There is no downside as far as I'm concerned.

My car shifts from 3rd to 4th at about 43 mph. Used to shift at 40 mph (before the Pro Built Automatic Street/Strip TransGo). I like that it shifts at 43 because it just feels like the spot you would shift if you had a manual transmission. I'm guessing the added boost valves upped the pressure and that causes the slight mph upshift.

Once you're in 4th, it tends to stay there unless you give it a good shot of gas. Since the L98 has lots of torque, you generally don't need a downshift unless you really want one. Slowing down to around 42 mph or so and it will automatically go back to 3rd. It's just that with the modified plunger sleeve in there it won't do the constant 4-3-4-3-4-3 shift at light throttle.

The modified sleeve made it so my car would downshift from 4th to 3rd at anything below 85 mph and stay in 4th at WOT (or any throttle for that matter) at 85 mph and faster. Putting my foot to the floor at say 80 mph, the car would shift 3rd to 4th at 5000 RPM.....Unfortunately the car stopped doing this. And now it's just like there's a stock plunger in there.

I believe Sonnax also makes a "cop car" plunger sleeve without the part throttle holes on it. Allowing the 3-4 WOT shift.

I never really made many 3-4 shifts with the modified plunger sleeve. But having it was nice for going from 70 mph and gradually taking it up to 100-120 mph and cruising without fear of getting a downshift to 3rd. You didn't have to tipsy toe the gas pedal at 100+ mph.

85 mph with my 3.27 gears is 2500 RPM in O/D. You don't want a downshift at that speed unless it's absolute full throttle max speed. Even then, it accelerates fast enough in 4th that once you're above 3000 RPM (100 mph), you're at the torque peak. Not much point in using 3rd. Although you could if you did a manual downshift.