My trans is shifting way early, 2.nd at 10mph, 3.rd at 24mph, 4.th at 27mph.
This during light acceleration. At WOT is shifts around 3000rpm.

What is considered normal for the 700r4?
Would be interesting to hear which shiftpoints those of you that have this trans get.

 

Automatically shifting, the car shifts at about 3800-4000 rpm at wide open in first, 4500 in second, 4000 or so in third.
I prefer to manually shift, at least out of first and usually on the freeway to get a little better accel. (I have the 4-3 kickdown prevention servo, and the car really doesn't want to shift down past about 65-70 mph.)
I have always thought this tranny shifted way too early. I usually hold first up to just under 5k when I'm trying to go -fast-.
-Steve

 

Thanks!
As far as i can tell I will have to drop the crossmember to get to the govenor. A lot of work and I'm not tempted to do it at the moment unless I really have to.
To me the shiftpoints seems so low that I suspect I might have another problem. TV is correctly adjusted and is max at WOT.

The trans is from a Caprice and the govenor hasn't been changed.
Original speedo gears was 18/35 and I had to replace them with 17/40.
(Does the Caprice really has that low rear end / big wheels??)

So it seems likely that I need new spring/weights in the govenor.
But according to the information in my TransGo kit, these parts are related to the engine type, not the rear ratio/tire size.
This seems strange to me...

The real problem is the 4th gear. When the lockup kicks in I end up at 7-800rpm.......
Also the trans refuse to downshift from 4 to 3. Well, it shifts, but immediately jump back to 4th and so on..

I'm using the original TH350C vacuum switch. This is connected to ported vacuum. But somebody told me that carb cars with 700r4 use normal vacuum.
Any thoughts on this?

 

Your govenor is made for low rpm. It was made for a smooth shifting family car. Correctly modified 700's should never do a 4-3 down shift. Original 700's could never use WOT in 4th because they would down shift.

You need to put your car in second gear on the gear selector and do 3-4 runs with WOT from a dead stop. Just watch the RPM that it shifts at. As you increase the govenor shifting points it also raises the easy driving low rpm shift point.

I took out my 6800 rpm original because it wouldn't even shift till well over 3000 rpm. So I would have to go 85+ mph on the highway to get it to shift into 4th and the lower gears would hit so hard it would chirp the tires.

I don't have vacuum to my tranny. :confused:

 

Ingar, you vacuum control goes to manifold vacuum source....
to adjust throttle linkage, press tab on adjustment, and pull outer cable shroud away from carb linkage as far as you reasonably can....
release adjustment tab, then force throttle linkage open far as it will go, pulling the tranny cable shroud through the stops with a clicking sound....
that's how it's done by my tranny guy, and me too, works like a charm....
I had to modify my governor assy also...just remove it and look at the assy, you will see extra weights spot welded onto the flyweights....take assy apart, but remember how it goes together, it's trickey....and remove/cut weights off while flyweights are on a workbench...I used a plain old finishing nail to hold my governor together again....works fine...
that upped my shift point to something totally liveable....BTW, I have a similar tranny--700r4, 336 rear, and '72 vette....and a 350 engine with DPFI...

GENE

 

Ok, I will try to open the govenor. It's a lot of work since I will have to drop the crossmember.

Gene: I thought you had to replace the weights, but I will check if my weights has a "removable" part as well.
Don't understand what you mean by "finishing nail", the weights are held by a pin?
I have adjusted the TV as described.

I'm confused about the vacuum switch. Originally with the TH350C it was driven by ported vacuum.
This switch is closing at very little vacuum so I would have to get another (adjustable) switch if it's to be connected to manifold vacuum. Or else it would just be closed all the time.
Strange that the 700r4 operates in the opposite way.
The purpose of the switch in the Th350C is to unlock in idle, the 700r4 on the other hand should unlock at heavy throttle. Right?

I found some more info in a TCI instruction sheet:
Connect the vacuum switch to a ported vacuum source on the carburetor or throttle body. (If you find that the TCC operation is erratic in your application, then you may try moving the vacuum source to the manifold.) The TCC is now set to engage automatically in 4th gear only when engine vacuum is greater than 8-10 inches. The converter clutch will release when the transmission is down shifted out of 4th gear or engine vacuum falls due to increased throttle.

They say to connect to ported vacuum, but the rest of the text indicate the opposite.....

I include another image series that shows (left to right) the various stages from fully open (zero speed) to fully closed (high speed) govenor bleedoff valve. (from the TH350C)
The valve is only directly affected by the inner weights. Which in turn is pushed out by the outer weighs through the springs.

 

From what I know, no 700r4 ever used vacuum. Its all controlled by the TV cable and govenor. I too need to do some work on my 200R4 govenor. It shifts now at 4000 WOT. It needs to be closer to 5000. Also something it wont do is shift from 3rd to 4th at WOT. To get it into 4th I need to release the throttle for a split second and slam it back down again. Once in 4th at WOT it will pull up to about 3500 rpm at 130mph and then suddenly kick down to 3rd :eek: I know it shouldnt be doing this.


[Modified by Jvette73, 6:16 AM 4/9/2002]

 

Ingar, you know, I may be rong about that vacuum switch arrangement, you see I would have designed it to close the electrical part therefore sending 12 volts through the TCC solenoid in the tranny and locking it up under say 6 inches or more of vacuum...but they could have designed it to do just the opposite, but those ported vacuum sources can be very scatterbrained depending on airflow charactoristics...air cleaners, etc....it's a much weaker signal, I would say...
the TCC is supposed to be fed through a 12 volt switch on the brake pedal...pressing pedal removes +12 from high side of TCC, now on the ground side there may be anywhere from 2-4 swithces inside the tranny, the 2-3rd gear switch is on one valve of the body, as is mine, and the 4th gear switch is on the 4 gear valve....and they are all in parrallel....so what happens is IF you directly ground the 'bottom' end of the switches, the TCC solenoid activeates in 2-3-4 thgears....with very momentary opening in between gears...
which saves TCC from undoo wear of tranny shifting power...
NOW in a full computer car, the bottom of the switches is connected to the computer, and THAT is the final determinator as to wether the TCC solenoid is activated,...factory at around 25-30 mph, aftermarket chips at 50 mph...
that is why the early C4's had sucha terrible drifty feeling in slow cruise around neighborhoods, all the time locking and unlocking as the computer never would make up it's mind...as if the tranny was slipping in and out of gear all the time...some guys thought it was shifting all the time....
In fact in my car, I have a dash operated switch and a brake pedal switch arrangement off the brake lights....with a relay, so that my manual switch can select from solid ground, giving a stick shift feel to the car at lower speeds, or flip it over to the computer controll side, whre the hotrod chip won't lock untill 50 mph or so....
if you look at my sig file you see a rather complicated dash, and that's an old eary pix.....it's grown since then....

GENE :jester :jester :jester :D :D :eek: :cool:

 

John:
Computer controlled lockup doesn't use the vacuum switch, but as I understand it it's recommended with carb control.

 

Thanks again Gene, your car is really awesome...!..:-)

Yes, I see the panel..! Could you tell a little about what other functions you have there?

I've added a auto/on/off switch myself, a small 3-pos toggle under the ashtray lid. Also have a small LED indicating when TC is locked up. (Not really necessary on the 700r4 as the RPM drops nearly 500 when it kicks in..!!)

I've never heard anyone else that has switches for lockup in all gears. Must be good for milage and keeping trans cool...
Do you have any picture of the valvebody with the switches? How many do you have?
I'm using 4.th gear and 4-3 sequence.
Have some info on this and how I've wired my lockup at my page, tech section, 700r4 article.