Hello all,
I have a 1989 Pontiac Firebird with a 700R4 tanny with a B&M Shift kit installed. My buddy and I are have a dispute over 4th gear. I have the tanny in OD and I am at WOT at 4500 RPM will the tanny shift gears to 4th or must I left off the gas to have it change. He says it will always stay in 3rd until either the engine blows or I come off of WOT. Who is right, I say it will change and act like a regular gear. Any comments. Yes I will try on the road, but would like some feed back on how this OD works.

Brad
San Diego

 

If you have it in OD and go mnore than 1/2 throttle it will shift into 3rd and stay there until you let off.

 

Ok, but how can I make it shift in 4th at WOT, to make the 4th gear like a regular gear?

 

Ok you cant completely correct it but you can help it. Jegs part #890-374400.

Its a TV plunger that allows you to go to 85% throttle in 4th gear before it downshifts. Instead of 50% like stock ones.

This is about the only safe way to do it.

 

I think you can also buy the b4c upshift valve to solve the problem and then you can go wot into 4th gear.

 

im gona have to get 1 because i was on the hwy at wot and it whould not shift untill i let off then when it did shift i punched it again and shot back to third so im gona have to invest in the plunger . does that hurt the tranny

 

If you use that magical button, all your questions will be answered. You will find out what methods can be used to obtain 4th gear @ WOT (three are currently available, new 3-4 valve lineup, billet TV plunger sleeve, or modifying your current TV Plunger Sleeve) you might also learn that it doesn't hurt the tranny, however, you will loose detent downshifts, which means that if your on the highway and want to "kick it down" to pass, you'll have to do it manually (put the shifter in Drive (3rd). So go ahead, click that and prepare to be amazed.

 

GMTech, out of the 3, which would you recommend and why?

 

.....which would you recommend and why......

None!

What purpose do you have to be at WOT on the highway anyway?

Be realistic brother. We own/drive/tinker with these cars because we appreciate them, not so that we can get stupid in them.

RB

 

sounds good but your gonna burn up the overdrive band

 

The cheapest is the "modifying the existing TV plunger sleeve". The cost of 2 small Allen screws $0.34 total to block the 4-3 part throttle passages. Yes, after this if you are going about 80 mph, it most likely will not downshift at WOT in the OD position, so you must grab the lever and bring it back for a manual third gear.

 

I modified the sleeve on the valvebody on my 700R4 and have not had any problems, mind you I did it because I installed a 3:73 out back and didn't want it to downshift on the freeway when I passed anybody. I didn't do it to obtain big numbers on the top end. So my tranny has held up just fine. And yes, you have to manually shift out of OD to grab any lower gears once you get into OD. No biggy to me, I want my car to be a "Car Guy Car" that way my wife won't want to drive it.

 

I installed the B-car 3-4 shift valve. It won’t shift down from OD below 70-75mph, but I have made other modification as well (I don’t know whether the TransGo kit and boost valves have any influence on this). I like the possibility to stay in OD when passing cars at higher speeds, but my next mod after the 3-4 valve was a ratchet shifter....

 

can't you just use the stock GM part #8673948 that is offered with the police packages?

From the tech articles I state
I take it that the B&M kit lets you do 75% WOT and the GM part let's you do 100%..
So why does everyone keep referring to the TV plunger, does this valve not do the job

 

That's the one I have.

 

The GM kit is an actual 3-4 valvetrain replacement. It comes with a new sleeve, shift valve and shift timing spring along with valvebody gaskets.

The "upshift" sleeves are are sleeves in which the TV plunger sits in, with a modified, or deleted "detent" hole. Detent fluid forces a downshift at a certain throttle, based on plunger position. By modifying or deleteing, you can move or ommit a forced downshift.

 

so if you could chose between spending $30 on the B&M Kickdown kit with 75% throttle downshift

OR

$15 GM replacement part.. which is what you described..


which would you pick?

 

my 88 Formula will upshift to 4th gear at WOT.
At about 5K it upshifts, mph is about 105.
There's a burning smell coming from the car when I slow down though, smells like burning clutch. someone mentioned the 4th gear band or clutches are slipping. I am not an Auto person, this is the first auto f-body I've owned.

 

you're only @ 105 MPH when you hit 5k in OD?
****..
I'm in my 3rd gear doin 120 MPH @ 4500..
DAYUM!.. can't wait to see what I hit with O/D..

why is your MPH so low?
I mean.. what do you run in a 1/4 Mile if you top out at 105 MPH?
wuh..

 

No, I am at 105 in 3rd at 5K when it upshifts to 4th.
It accelrates great to about 100 then it pulls slow, like it's slipping and then I smell a burning clutch odor.
My LG4 5 speed was faster than this.

 

Something doesnt sound right here. If you have 3.23s then you should be going a lot faster than 105 when you upshift at 5,000 rpm. Only thing I can think of is the torque converter is slipping really bad!

 

dp

 

That may be a possibility.
I am going to double check the fluid today to make sure it is full.
I changed the filter and fluid last weekend. Maybe I didn't put enough in there. Looked good on the dipstick, but the car was only running for a minute or two. I put 5 quarts of that B&M Trick Shift in the tranny.

 

That trick shift crap is no good. It has no friction modifiers in it and while it may feel good at first, I've heard it does bad things to the tranny in the long run.

 

What should I run, just plain atf?

 

Regular gm dexron 3 would be good. Also redline synthetic is good and so is mobil 1 atf. In the past, I heard mobil 1 wasnt so good, but it seems much better now and it is a good tranny fluid to use. It is what I plan on using in mine when I flush everything out. Check this thread out.

https://www.thirdgen.org/techbb2/sho...hreadid=184952

 

thanks, I'll look into the Mobil 1.

 

No problem man. Glad I could help.

 

back to my original question..



??

 

The gm one will let you go full throttle into 4th where as the B&M will only let you go 3/4 throttle before it downshifts again.

 

I have the B&M as well, does the same thing, i need to let of the gas in third just a bit, and into fourth it goes. doesn't affect speed mich. It was free, so who cares. I dont know.

 

I'm looking to top my speed out.. so I want the full WOT..
gonna try it just once.. then throw on some 3.42's.. cuz I mean.. how often do you really do 150-160MPH?

 

I'm looking to top my speed out.. so I want the full WOT..
gonna try it just once.. then throw on some 3.42's.. cuz I mean.. how often do you really do 150-160MPH?

 

Cool, but make sure you got some good tires man, you don't want them coming apart on you.

 

I've got Radial T/A's.. they SHOULD hold up.. I know they're not rated to go that high of speed.. but I've been 200 on tires rated for 140 (winter tires), so I'm pretty sure they'll hold up..
and if not.. I've had a good run..

 

well, I'm just going to do it once.. at the crack of dawn..
then never again.. just to set a personal record and to see what these f-body's are all about..

 

I here ya, I want to do the same thing some day and see if my T/A will do the 140 that the speedo says. But I have a set of white letter tires that are rated for only 112. I spent so much money ($9000) on the car this year that I had to go cheap on the tires. Next year though I want to get a new set and see what she will do.

As for you guys that talked about the GM sleeve for WOT OD, I just ordered the sleeve yesterday, is there anything else I will need like the piston that goes inside it? Or is the one I have identical to the one used in the police package?