Haggisbash

Shop has installed the trans I had built for the car and imported before Christmas but it upshifts way too quickly. Its trying to get into 4th gear on a light throttle at about 30mph. TV cable was set for WOT and at idle has a very slight amount of slack in it. Where to from here? TV valve spring or lightening the governor weights? I am pretty disappointed that it wasn't closer to what it should be because the trans builder knew what car the trans was being fitted to. I'm having nightmares about having to change the valve body/governor assembly as each change takes two weeks as all the parts have to come from the USA. The car has been in the shop for nine weeks now for what I thought might take a week before I took it there.

johnt365

I have a 200-4R also and understand the concern you are having.

Here is what Chris at CK Performance told me to do.

1.Remove the TV cable from the carb
2.manually rotate the throttle at the carb to the WOT position and hold it there.
3. pull the cable end out to that point. It may be necessary to adjust it to that point.

That is a baseline. I have a CZ valve body, .555 boost valve and performance servo. If the TV is to tight, it will shift quicker and hard. His advice was to adjust the TV cable forward, one notch at a time.

Move the cable one notch, then test drive the car. As soon as the car shifts to second, punch it!. It should downshift back to first. Keep moving the cable forward until the downshift is lost. Then, move it back a notch or two.

These suggestions worked for me. After you get the cable in the ball park manually you may not need to street adjust that much.

Is the shift hard or just fast?

wombvette

You can buy a governor kit to adjust it. One kit has lots of weights and springs, makes many combinations. I adjusted mine to drop into OD at 45 mph and come out at 35. Makes town driving a dream without the hunting.

7T1vette

Setting the TV cable correctly is the most important aspect of installing a 200-4R or 700R4 transmission. The transmission uses TV pressure (Throttle Valve pressure) to regulate the shift timing and firmness properly. As the TV cable is pulled out of the trans, TV pressure increases. So, the further you press on the accelerator, the firmer and later the range shifts are made.

The placement of the cable connector pin on the carb throttle linkage is important. Selecting the best mounting hole in that linkage for the connecting pin (or redrilling a new one) is the first step in getting that cable to work properly. It would be difficult to tell you all the steps required to do that, but what needs to happen is that the TV cable should be at the start of its travel when the throttle is "closed" and very near the end of its travel when the throttle is at "full open" position. If you were to connect a pressure gauge to the TV pressure port on the left side of the transmission, you could watch the increase/decrease of pressure as the cable is moved in and out. Ideally, you would want the cable to be adjusted so that at "closed" throttle, the TV pressure is just at the start of increasing pressure; and at "full open" throttle, TV pressure has just reached its maximum point (still prior to the end of cable travel). THE CABLE SHOULD NOT BE 'LOOSE' OR REACH ITS FULL RANGE OF TRAVEL AT ANY TIME once it has been properly adjusted to the carb throttle linkage.

Hopefully, you will be able to understand the concept of the TV cable and its relationship to the throttle cable/linkage. If you do hook up a pressure gauge to the trans, you can measure how much cable travel there is from the onset of pressure increase to maximum TV pressure. That distance is how far (linear distance) the cable attachment pin must move from "closed" throttle position to "full" throttle position on the carb linkage. Then, adjust the length of the cable so that it is just at the beginning point of TV pressure increase at the "closed" setting. That should set it up correctly.

If you need other details or clarification, put another update post to this thread or send me a PM with your questions.

P.S. IMPORTANT!!! If you are working with the carb throttle while on the car, make sure that you disconnect the accelerator pump arm so that it is not constantly dumping fuel into your intake while exercising the throttle. If you do not disconnect it (drive roll pin just far enough to release that lever arm on a Q-Jet carb), raw fuel will collect in the manifold and it could explode when you first fire the car!!!

Haggisbash

Hi, thanks for the replies, I have not driven the car as yet. It has only travelled about six blocks from the trans specialists to the exhaust shop and back so I'm going on the mechanics description, he said the shifts are firm but just too quick. I'm thinking of getting him to verify that pressure is building as soon as the throttle is touched and then getting the car back to finish myself as its all taking far too long and if he has to go into the PAN again I will be bleeding money at $70.00/hr.
7T1vette, I'm well aware of the accelerator pump issue but I sometimes wonder if mechanics bother to disconnect them when adjusting things ( its all right for them you will be back sooner when fuel dilution and bore washing have reduced the life expectancy of the engine considerably). One of the reasons I installed a manual choke (the car had none when I got it) I dislike the practise of repeatedly pumping the gas pedal to start the engine when cold because it can cause bore washing. With choke my engine starts per the handbook, one pump with full choke and as soon as it fires open choke almost completely.
JohnT365. I am confused on this cable adjustment issue somewhat because for every post on the web saying adjust the cable I find another which says set it initially and then under no circumstances use it to adjust the trans behaviour. Still to make my mind up about this, but thanks for posting your specs that give me a guideline as to what works when the 200R4 is installed in a vette.

7T1vette

If you are using a GM TV cable, bracket and have the cable mounting pin already located in a "correct" position (per GM requirements), the instructions for setting that cable may be correct. But, if your cable mounting pin is not in the correct position (relationship to the center of the throttle plate shaft), you can't assume that process will work. In fact, you must then assume that it will NOT work.

If you have about 1/8-1/4" of TV cable movement 'out' of the tranny when the throttle is closed, and 1/8" of [unused] cable travel remaining when the throttle is at "full open" position, your TV cable should be reasonably well set. At least, you shouldn't be frying any tranny clutches when you put the "pedal to the metal".

Also, the TV cable SHOULD NOT be used to adjust shift points. Your "max" shift point at W.O.T. should be adjusted with governor flyweights and springs.

Haggisbash

I may need this kit, where did you get it?

diehrd

http://www.jakesperformance.com/TV_C...etup_Info.html

johnt365

There are a lot of factors in this conversion. I am not an expert by any means. I would recommend getting the pressure gauge and taking some readings to verify your min and max pressures yourself. mine were low before I made modifications.

The TV pull geometry needs to be verified as said. I spent an afternoon making sure my throttle cable had no slack and the brackets and connections were where I wanted them.

After the shift recalibration kit and Servo installation, My car was shifting into second very quickly, within a few feet. I checked the pressures before the change and after the change. I knew I had instant pressure rise and good minimum tv pressure after the changes.


Did your transmission get any modifications or is a stock rebuild?
My TV cable for sure does not have any slack. Its not sagging at all. I know its hard to be away from the car for that long but if there is a warranty involved in the trans. work I would want get an "all good" from the rebuilder/installer.

confab

Do that.. Have them put a pressure gauge on it and verify the line rise. It should be as responsive as a tachometer.

With a custom install, you don't want to just check MAX PSI either.. But the RATE of rise. This is critical.. For example, if this gets goofed up even a little bit, you can take the 3/4 clutch out of a 700 on the test drive. It just has to be right.

Further, I saw an aftermarket LT1 throttle setup in a 57 burn the trans several times because the TV pivot connection was in the wrong place. It was set for a kick down cable from some other trans, not a 700 TV cable.

Max Pressure looked fine.. But if you watched the rate of rise, it dropped off just enough to lose pressure and burn the clutches out of it. Moving the pivot fixed it.

Generally speaking, you don't use the TV cable to tune the shift points in these cars. It's all about line rise. Under moderate throttle, you should get a 1-2 shift in the 18-22 mph range. If not, you may have a sticking governor/spring weight issue, pressure issue, or an issue in the valve body.

Never was very familiar with the 200, but I know TRANSGO had governor springs for the 700/4l60 to give you some adjustment with their shift kits.

I can't even picture a 200 governor right now.. (I think they were a weirdo thing in the VB area?) but if they're like the 700 governors... If you had a sticky one? Try washing it out real good with mineral spirits and working it a bit, then toss it in the freezer overnight. (Srsly) Then wash it again in the morning.. and your governor problems will vanish.

PS: dirty coolers will stick the governor (and can stick the rest of the controls) almost immediately on a hydraulic unit.. That cooler should have been cleaned thoroughly.. You can run one on the lift, sans governor/no load!, to flush the circuit if it's suspect.

Good luck!

Haggisbash

Thanks guys I'm not taking the car home until the pressure rise etc is confirmed.

Haggisbash

Okay, so mechanic has road tested the car again and found that the 1- 2 shift is good 2 -3 not quite so good and on a light throttle opening when in 3rd as soon as you lift your foot the trans moves into 4th, apply gas moves back to 3rd, I can see this will be annoying:-( Shifts are a little too firm so I guess shift kit was not needed after all.
Also, trans is leaking oil :-( either from the breather, most likely the from the accumulator cover or a cracked case. Leak is on the passenger side and is not coming from the cooler lines, connections or pan gasket. he is double checking that it is not overfilled before he takes it out. So far not impressed with imported rebuilt transmission! RPMs are approx 1700 in 4th at 60 mph so I expect will be well overgeared when lock up applied, I will cross this bridge later change diff ratio.

confab

Line rise good? What speed are you shifting 1-2?

IMVHO:

Don't worry about your diff gearing,. The most important thing is to make sure you're not burning it up with low line/bad rise, (Especially where you are located and all the difficulty that adds to this swap, shipping stuff around.) get your leak figured out, and tune the governor to correct that.

Best wishes.

confab

PS: What johnt365 said about the 1-2 shift is absolutely true. As soon as it shifts to second, there should be enough TV to put it back into first under hard acceleration.

The problem with that test is, if your rise is bad? You'll likely damage the transmission.. So, it begins and ends with line rise and rate.

diehrd

What rear gears do you have now ?

Haggisbash

3.08 installed at present.

diehrd

No matter what you do with that gear your gonna not be happy with O//D

Haggisbash

Hi, I figured that was most likely going to be the case but I want to get the trans finished and working properly before tackling the diff.

Haggisbash

Next question is, what is the best way to control the lock up for the O/D in a vette? I have an adjustable vacuum switch but it has been suggested that the painless kit would be the way to go. Seems there are a few options!

confab

With hydraulic units like the 200 and 700, and no ECM control, it really should be wired into the brake light switch to kill the TCC when you hit the brakes.. This prevents a bind up and dragging the clutch.

(A cruise control style brake light switch has a second set of contacts you can utilize for this, they work opposite the set that turns your brake lights on.. So, lights come on? TCC goes off.. )

To turn the TCC on in the first place, a pressure switch with a delay works well. (The 700's are 1/8" pipe thread and the 200 is probably similar) Plumbing it into the VB behind the shift valves is my preferred method.

If you want to get fancy/schmancy, you can use a thermal switch (Standard on the 700 and it will retro to your trans, if it doesn't have one already.) so lockup doesn't come on till the trans temp comes up.

Whatever you do, it should be fuse protected and you should make sure you have the polarity right before you power it up.. As there's usually a diode in the TCC solenoid that you'll fry if you get it backward.