NEOMASTERZ28

just wantering mine does shift after 3rd about 4800rpms then goes to 4th at full trottle i heard that its not supposed to do that in full trottle ?????

85 z28

NEOMASTERZ28

no bodys car does this:nono:

RB's84camaroF-41

only B4C cop cars

Momar

The b4c's had a special valve in the transmission that allowed this. You can also buy that part from gm, or b&m makes one and it will upshift into 4th at full throttle.

Ben

paulo57509

I've always been too chicken to drive that fast to find out.

Pro Built Automatics

Are you saying that the shifter is in the OD position and at 4,800 rpm the 3-4 shift happens? If this is the case then hold the lever in third gear till you get to the rpm desired and then move the shifter to fourth gear. 1982-86 had this feature.

Momar

Are you saying that all 82-86 cars had the full throttle upshift? I have not tried it because with my 2.77s I am able to go quite fast without fourth, but I have a set of 3.45s in the garage that will be going in soon. I have an 85. Does that mean that my tranny will shift into 4th at full throttle?

Thanks

Ben

cp87GTA

You mean you don't have that rearend in YET! Ya waitin for spring? I just bought new eaton posi, 28 spline moser axles, and bearings today for my GTA. I'm going to keep the 7.5 10 bolt in it for now. Still thinking about the 4.56 gear though.

Momar

Actually, my garage was a total disaster. I had like a car and a half worth of parts. I spent a fair share of my free time this weekend cleaning it up and getting rid of some junk. I was making room to set the rear up on saw horses because I am going to attempt to sand and paint it. I am going to use drill accessories, because it would be nearly impossible to clean that up by hand. Those axles and posi should strengthen up that 10 bolt though. Are you going to get a girldle? If by some miricle the snow melts it is supposed to be mid lower 60s friday and mid 50s saturday. It is supposed to rain friday and I think scattered showers saturday. I was wondering, if it is dry and actually that warm, would you mind me coming over and going for that ride, or do you have your rear appart to put in your new axles?

Ben

RB's84camaroF-41

damn had no idea that 82-86's can shift to 4th at full throttle, since i can do 130 in 3rd i dont think i'll be trying it out any time soon

Synapsis

Anyone have more information on the aforementioned valve that lets you upshift into 4th at WOT? It's really getting annoying when I'm racing someone and I have to go to half throttle at 95 mph.

Momar

BMM-70249 I just got this number off of www.summitracing.com It is the part number for the B&M version. I think that the origional gm one is cheaper though. Eh, what the heck, http://store.summitracing.com/defaul...rchType%3DBoth

NuclearPwrIroc

Id hate to say this, but very few 700r4's had the abillity to make a 3/4 throttle upshift. some iroczs, gtas, vettes had a 3/4 throttle upshift. but most had a 1/2 throttle upshift. You can get a 3/4 kick down valve from b&m....works great....unless you get a full manual valve body it wont do that....besides if you are clearing the 1/4 mile going into 4th gear.....you need to get bigger gears......you shouldnt really be racing in an overdrive range.....just doesnt make sense to race in a gear where you have less torque....i dunno

Momar

I think that most of us here realize that most of the 700r4s will not upshift into fourth at wot. That is why we were talking about the parts that make this possible. As far as the drag racing, thats not what everyone uses there car for believe it or not. Besides what if someone has the right gear for there quarter mile efficiency, and this only allows them to top out at like 105 or something in third. Maybe they want to be able to go faster than that when racing someone on the street, not that anyone here races on the street. Or maybe they just want to be able to say that they have a high top speed whether they use it or not. I myself would like to hear from probuilt again about his coment on the 82-86 tranies. I believe that probuilt knows very much what he is talking about. Did you actually mean that all 82-86 cars had an ability to upshift at wot into 4th? It would kind of make sence, because that is when the major valve bodie changes occured I believe.

Thanks

Ben

Pro Built Automatics

Major valve body changes (whole new design)(all new 3-4 upshift valve & sleeve) started in 1988. There were variations on these valve bodies, but mostly on the TV plunger sleeve. There is a 4-3 part throttle passage that is uncovered at certain throttle openings. This passage varies in placement from model to model. The closer the passage is to the top of the plunger sleeve the easier it is to get 3rd gear and harder to make 3-4 WOT shifts. The further away the passage is from the top of the plunger, the harder it is to get a 4-3 downshift and easier to make the WOT upshift to 4th. In 1991 & 1992 Corvettes I have seen, this passage is eliminated, once in 4th gear at freeway speeds it will not downshift to 3rd gear at WOT, you have to grab the lever if you want 3rd gear. There are other variations that affect this some, but the position of the 4-3 downshift passage on the TV plunger is the main one.

Momar

Sorry for my confusion, but what does that mean for the 82-86 models that you mentioned earlier?

Pro Built Automatics

The early valve body allowed 3-4 WOT shifts due to its design, in fact if you leave it in 4th it will upshift third gear to early into 4th at WOT. You will need to (in most cases) hold 3rd gear longer before moving the lever to 4th. Why they changed this on the late design valve bodies, I do not know.

RB's84camaroF-41

I'll be trying this out soon, hope it works

NEOMASTERZ28

WELL i bought my car for 2,000 off an old race car driver and he said he did not do anything to it but i have the feature shift to 3rd to 4th at full trottle

Momar

What year is your car?

qazd

My 87 Z-28 shifts just fine (3-4) at wot, I am the second owner, and I know the tranny is factory spec. I'm just reading this topic and scratching my head, i guess i'm lucky

NEOMASTERZ28

IT is an 85 z28 but i dont know what the race car old guy did to it but i know thats what it does shifts around 120-125mph to 4th

hahah its scary sometime but its cool

Changa2

My '87 has an '86MY tranny and a 2.73 Rear. Last Fall, after putting a new engine in it, I went to 'Test-N-Tune' just to get a feel for how fast it would be.

I noticed that just before the end of the track, at 4800 RPM and about 100MPH, it shifted.

The code is: 6YWM-4-00300647-255A

FWIW

Momar

So, with that being a 2.73 were you just going into 3rd though? I know that when I had 3.08s I could hit like 40 in first. Then I had 2.77s, but the speedo was never right to know. Now the 3.45s are going in. I am actually going to change the speedo gears this time too.

Ben

chevyboy07 91

My 92 Z shifts into 4 at WOT. I was under the impression that ALL 91-92 Z's did this.....hmm, Also, I have an SLP shift kit in it too

Momar

When I finaly get T/A car done I will have to try it. I origionally was just replacing the 305 that died with a stock 350 running a computer controlled carb. Well.... that all changed. I have bought a new rear end, had the heads and intake ported, put a corvette servo in(already had shift kit), possibly going to pbr rear brakes. I put a megashifter in that I got for practically free. I also am buying a set of valves off of ebay, as long as I win and putting a set of performance valves in the heads, I am buying a cam(pretty sure on which one, but know someone who has it and am going to ride in his car first) and valve springs. I am also going to be buying a set of hooker long tubes and either dual exhaust with x pipe that dumps before the rear axle or a mufflex y-pipe. Well, this isnt really related to the topic whatsoever so I guess I will stop, but let me just say that I was lucky that I had another car that I could drive because I think that this project will be well worth it when I get it finnished.

Ben

Synapsis

"Well, while I have the engine out, I could port the heads.... while the heads are off I could put in better valves...."

"With the heads out, putting in a cam would be a snap..."

"It'd be really easy to fit some headers and exhaust while the engine's out and the heads are off getting worked..."

"Since the car's not moving anyway... I could do some work on the rear..."

"How come this 350 upgrade cost me 8 grand?!"

Momar

Its not cost that much yet, but thats what happens or in my case is happening. lol

Ben

Momar

Actually what has made it really easy to decide to get all of this stuff is because first, I was told by a guy that I could have everyhing off an abandoned 87 T/A that he had with exception to the motor its self, and the wheels for 200. Well I striped that car and sold some of the stuff. It had a tpi, megashifter the ground effects, t-tops, 145 speedo and so on. I sold the tpi for 375 so I made a 175 profit right there and got a free megashifter, I sold a couple of other small things and still have some of it. I also got money for Christmas and my birthday, and now am getting more hours at work, and have a 500 dollar tax return coming. I am 19 and live at home while going to college so dont have a house to pay for, just insurance, phone, gas, and stuff like that. Well the rear that I got is a 3.45 9 bolt. I bought that with the money from the tpi and have only had to pay for about half of the rest of the stuff so far. Another thing that I forgot to list that I am going to do is have sfcs put on so I dont tear up the car I am putting all of this money into.

Ben

Pro Built Automatics

I should have stated the 1987 has the early (1982-86) valve body, so it has the same characteristics. 1988 was the first year of the 2nd design.

Momar

Thanks for the info.

Ben

IceBlue91z28

My car shifts from 3rd to 4th at wot. It didnt do this until I put in a hypertech thermomaster power chip and that made the tranny shift better. Dont know how or why but it did. Just my $.02

Changa2

But at what MPH and RPM does it make that shift? and what gear are you running?

Just curious.

NEOMASTERZ28

i have an 3.23 limted-slip

LottaBallsCamaro

I could have swore that 87 was when they changed the valvebody.

Momar

That is what I thought also.

Ben

JPiroc87

Just to confuse you all again: I have an 87 Iroc (350 TPI) and it will downshift from 4th to 3rd at 125 mph, if I give it more than 3/4 throttle.

I want to eliminate the 4-3 downshift at high speed, keep the automatic kickdown at lower speeds and have WOT 3-4 upshifts. The B-body 3-4 shift valve, GM part #8673948 is supposed to give those features, but I don't have any solid evidence (yet).

RB's84camaroF-41

last time i tried to order that part they sid they couldnt have it any time soon because it wasnt showing up at any warehouses. Do you already have it?

Momar

That would be a great piece to have. I have an 85 so according to probuilt I should not need it though. Hopefully that is correct because if I did need it I am going to have my tranny out soon and it would be nice to get that while I had it out.

Ben

Momar

Oh, and if we were right about the valve body changing in 87 instead of 88 that would make since on your 87 Iroc because that would be the newer valve body that would do that unlike the old style.

Ben

Pro Built Automatics

Of the many 1987's that I have torn down, I have not seen one with the late (2nd design) valve body.

Momar

Dont the B&M shiftkits come for up to 86 and then 87 and up? I dont know about the transgo kits. Oh well, I didnt know from experience, thats just what it seemed like everyone said.

Ben

NEOMASTERZ28

SO IS MY TRANNY good or what ?

Momar

I would not say that there is anything wrong with it if that is what you mean. That is a feature that some people spend time and money to get on there cars.

Ben

JPiroc87

RB's84camaroF-41: Yes, I have the part (or kit actually, because it also includes a boost valve and gaskets). The dealer didn't have the kit in stock, but it took only a couple of days to get it. I haven't installed it yet though. I plan to do it sometime in May.

There's a picture of the kit in this thread:
https://www.thirdgen.org/techbb2/sho...threadid=77850

As for the valve body change, it could be so that some particular late 1987 models got the newer valve body? In 1987 major changes were made to the case, pump stator, input drum, reverse input drum, low/reverse clutch assembly, VB/spacer plate along with the addition of an auxiliary valve body. In 1988 a new valve body was introduced and this VB further came in two different versions all until 1992. In 1993 there was only one (different) VB version and after that the 4L60E replaced the TH700. Between 1982 and 1993 totally 6 different valve bodies and 4 different separator plates were used. Some are interchangeable, many are not. [source www.transonline.com].
I'm not claiming that I have the newer valve body in my 87, but I do know that I can't do WOT 3-4 upshifts and the tranny will downshift to 3rd at any speed.

Regarding the B&M TV sleeve sold by Summit and Jegs: Some people on this board are happy with it, some are not. It will prevent part throttle downshifts, but if you floor the gas pedal, it will give a downshift at any speed. One member on this board had both in his cars and he definitely recommended the GM part. I should perhaps mention that B&M also has a similar part/kit, but this is not the one you will get from Summit or Jegs.

If e.g. transfixleo would see someone calling B&M a shift kit, he would start with a statement that ‘Shift Kit’ is a registered trade mark of TransGo and that all other kits only mask the inherent weaknesses of the TH700 instead of fixing them. Don’t take this as an offence Leo, I just paid ~$100 extra to get a TransGo kit instead of the offered B&M and Superior kits.

Momar

I know, I have seen him say it many times, but this is what the average person thinks of them as so I tend to refer to them as that because if you say something other than shift kit not everyone knows what it is. I believe that B&M call theirs a trans kit and transgo calls theirs a reprogramming kit. The transgo "shift kit" is only available to professionals and fixes many of the problems with the tranny. Anyway if someone is going to understand what you are talking about better when you say shift kit I dont know why I should say something else, that I have learned, that they are not going to understand. If someone really wants to or does know about transmissions they will know the difference either from looking into stuff or in the case of this board transgo does a great job of explaining it quite often.

Ben

JPiroc87

I agree with your comment. Most people (almost all) use the term ‘shift kit’ for any kind of modification to the hydraulic control system of the transmission.
My last comment was actually not directed to you. You have been on this board much longer than I have, but many people seem to have an urgent question, ask their question without performing any search and then disappear as soon as they get no new replies. I guess there is still a small teacher in me. (I was as a high school teacher for one year before I started with diesel engines. Many of the people I deal with through work today are actually much more difficult than high school students.... Repeat, repeat, repeat and once you get your message through to a few, then the rest will follow.)

TrasnGo offers several kits for the TH700. The Shift Kit and the Reprogramming Kit are actually two different kits. It is true that the TransGo kits require some more time and effort, but if you can rebuild an engine, then you can install a TransGo kit. Everything except the release spring for the 3-4 clutch and forward clutch can be installed with the trans in the car. The new release springs are only required if you intend to rev above 5000-5500 rpm.

Momar

I have a question. What does the auxiliary vavle body do? I have heard it mentioned, but what advantage is there to having a transmission with it instead of without?

Brian86IZ

I have the GM valve and have had it for over a year now. When I took the valve body off to put my Transgo shift kit in, I couldn't for the life of me figure out where the valve actually went. There were a couple holes that were similar size if I remember correctly. Does anybody have any experience installing it that can help me out. I'm going to have the valve body off again soon and would like to install the valve then. Thanks.

JoelOl75

It's a big mis-coception that the GM valve actually goes in the TV lineup (Where the 'kickdown' cable pushes)... The easiest way to tell what hole it goes in is to look at the end of the valve. It has kinda a 'half-moon) shape that no other vavle has... Just remove that one and replace the 1st 3 pieces (sleeve, spring, plunger) that comes out. There's more valves behind that, leave them in there!

Otherwise a piece of cake!