Alittle background. 1983 700R4, CFI. The guy I bought it from said that he just had the trans rebuilt with a "Corvette servo". When I got it, the 1-2 shifts were violent at WOT. It would usually break the rear end loose. I adjusted the TV cable and the shifts are more normal now.


My problem is that at WOT my shifts are early, my 1-2 shift is at about 4100 rpm, 2-3, 3500 and 3-4 is 2500. I took it to a local trans shop and was told that 3rd gear is gone and it's shifting directly from 2-4 and it needs a rebuild. I think the guy is full of BS, since I can feel it going from 1st to 2nd to 3rd to 4th.

Sooo, what do we think and what's my fix? Rebuild or something with the governor?


BTW, Happy New Year!

 

the trans probable came from a car with a much higher, numerically lower, rear axle ratio than what you have, so the shift points are off. The trans need to be adjusted, i believe its to do with the governor. A cheap "fix" is a TV cable spring that sonnax and other people offer. Its a little spring that attached to the TV cable at the throttle body and moves the shift points to a later point.

I did, hoever, use this spring when i still had the auto, along with a vette servo and the shifts were brutally hard and at 4500.

edit*********
oops, didnt notice this was a different car andnot just a trans...

 

Yeah, as far as I know, it's the original trans.

 

how did you adjust the t.v. cable. if u just loosened it until the shifts got softer then thats why its acting up on you. It only takes a few miles to ruin a 700 if its adjusted wrong, a few meaning under 10. Make sure you go to a very reputable builder i went to the shop around the corner and it only lasted 15k and never shifted right. building a 700 is an artform

 

I'm pretty sure it's set right, I followed the instructions found in various links on this site and others. I've put at least several hundred miles on it since adjusting the TV cable.

 

You know....

I wonder if I should try to re-adjust my TV cable, this time with a helper actually depressing the gas pedal vs me just working the TB linkage. I say this, because it sometimes seems more reluctant to downshift than I'd want or expect.

Any thoughts?

How would you know if you have an issue with the actual cable, ie., needing to replace the cable itself?

 

I agree with ATX.....DO NOT ADJUST SHIFT POINT AND FIRMNESS WITH TV CABLE!!!!! You will burn up that tranny so fast it's crazy. The TV (throttle valve) cable controls pressures in your trans that need to be correct.....sounds like you're running it at low pressure.
The shift points are controlled by the internal governor using springs and weights. The firmness of the shift could be the type of shift kit installed.

being reluctant to upshift, low shiftpoints, and soft shifts are signs of TV wrong adjustment.

I would increase pressure or re-do the whole proceedure.

 

Actually, it's a little too eager to upshift if you ask me. I'd like to see full throttle shifts in all gears closer to 4500 RPM rather than 4100--->3500---2500. I also think it should be more eager to downshift in many instances than it is right now. For example, sometimes when I give it heavy throttle, when I'm say in third gear - I expect it to downshift into second or even first (at lower speeds). Sometimes it doesn't, and I just chug along in 3rd (or whatever gear).

How do you adjust pressure beyond the TV cable?

 

well If its eager to upshift and doesnt want to downshift it sounds like the trans thinks your just cruising meaning something is wrong with the tv system. I would just check the cable to make sure its not kinked or burnt (when my trans failed the first time my cable was burnt and the housing had cracked off in complete segments) and try pulling on the cable with the car running it should be nice and smooth and pull itself back with a strong tension. My trans builder told me that the hook in the trans that latches on to the cable was bent and and the cable slipped off on mine so that might have happened. if you want to check the hook or replace the cable its easy. just use a 10mm socket on a flexible head ratchet to get the retaining bolt off then pull the cable housing up. Be advised that about 1 quart of fluid will leak out and the lever in the trans is spring loaded so it will pull itself down into the trans and have someone there to help you if not it can be very frustrating to keep em hooked up.

 

Just as soon as the weather improves and the snow melts (which may be awhile), I'll look at the TV again. I've actually adjusted it a number of times already, and this is the best I've gotten it. I did notice a teeny-tiny kink in the TV cable last time - I wonder if that may be having an effect?

 

well that's what I'm saying, if I understood you correctly, that you don't have enough line pressure. You need to make the cable tighter, so it opens more. For instance if yours has the box type on the throttle body with the little button on it.....then you need (with throttle closed at idle) while pushing the bottom on the side, push the sleeve over the cable back into the housing some. I can take a picture of mine if you need to show you what I'm talking about.

IThe way I understood....you want you car to shift higher like around 4500 instead of 3500/2500 at WOT.....if it's not that could indicate a mis-adjusted TV cable.
And then the tale tale sign that gives it away is the not downshifting when you hit the gas....mine will kick gears at anything over half throttle...yours should too.....and it should kick down into the highest gear possible very fast.
You might have a damaged cable, but didn't the shift points and downshifting work before you adjusted it????

the only way to adjust TV cable pressures, I think, would involve pulling the trans out....but you shouldn't need to do that. Another component on the trans that controlls shifting is the govenor, but unless someone messed with the weights and springs, then it should shift like it did from factory. I still think you jsut have that TV out of adjustment.
hopefully that helped some....adjusting that cable is sometimes a pain to get it just where it's supposed to be...

 

It would almost not downshift at all when I got it. Very rarely anyways. And the 1-2 WOT shift was lower - like around 3500 rpm - AND VIOLENT. I actually broke the tranny mount the first day I bought it. It was just horrible.

Boy, if this is all TV cable stuff that would be an easy fix. I mean it's WAAAY better now than what it was when I got it and it does downshift much of the time, but not always like I think it should. For example, if I'm in 3rd at 30-35mph, and give it heavy throttle, I think it should downshift into second every time. It mostly doesn't.

I've read all the tutorials, but if you have any pics handy I guess that couldn't hurt. I guess from the sound of it, I need to make sure the cable is pulled as far toward the fire wall as is can possibly go. There's no way that you can "over pull" it, is there?

 

Well if you pull it too tight you wont be able to go WOT because the cable will be at its end before the throttle blades are open. What I think you should do is take it to a trans shop and let them adjust it. They have a gauge that tells them what the line pressure is so that your not guessing if its right you will know. I dont know what it costs but it didnt look to hard when i watched them do it

 

First, (no matter whose valve body kit is in it) the TV cable must be tight (no slack) at WOT. This way it will have maximum line presuure at WOT. This will also get you the kickdown you want or should have. If the shifts are too firm at WOT, then the separator plate feed hole size needs to be changed. If the downshifts are sporadic, then this is a TV system problem, and a modified TransGo Shift kit needs to be installed. This kit will address the TV system, the accumulation system, and solve the downshift problem and line pressure rise problems. If you want the shifts to be slightly later at part throttle and the downshifts a little easier to obtain, then remove the governor and take out the weaker spring. You can do this with or without the Shift kit installed.

 

Thanks guys.

 

NOt to hijack this thread but my shifts are pretty weak as well in my 700R4. It downshifts from 3rd to 2nd and from 4 as well. If I am in second going about 20-25 mph shouldnt it downshift back to 1 at wot? Please help!!

 

***UPDATE***

After much deliberation and taking my car to three trans shops, my "mystery rebuild" 700R4 is shifting MUCH better. But it took some doing and shopping around.

1)Trans shop #1 said my trans is blown and there is no 3rd gear and I need a complete rebuild. I knew this snake was full of it, since I can feel my shifts going 1-2-3-4. Not having 3rd wasn't my problem. Next.


2) Trans shop #2. After a test drive, I was told that they'd need to drop the pan and valve body to see what's going on in there. $200-$500 for starters, then we'll see from there. Sounded reasonable, but then a couple of people recommended shop #3.

3) Trans shop #3. I left it there and I got a call to come and drive it since they had just adjusted the TV cable. Now, I had already adjusted the TV cable and rechecked that adjustment half a dozen times, so I wasn't hopeful. I got back there and drove it and it was EXACTLY the same. The shop owner said that they'd really need to disassemble the trans to figure out what's wrong with the previous owner's "mystery rebuild". About $1,000. I remembered Dana's comments (Pro Built Automatics) regarding the governor. So, I said can we concentrate on the governor first and see what happens? So they replaced the current governor with a Corvette governor ----and it pretty much fixed most if not all of my issues.



The only thing is, at WOT the 1-2 shift occurs at 5500 RPM. And the indicated redline on my Crossfire is 5000 RPM, so I'm not sure if I should fiddle with that or not. I've only driven it 20 or so miles, but overall I'm pretty happy with this "fix".