possible solution to 700r4 shifting problems

[kc8oye]

I just need to get one of these...

 

Shifting Solution

[Archer]

I would just spend half that and get the (constant Pressure Valve body) that way you don't have to mess with the TV adjustment. It maintains the pressure internally.

[Guest 72yellowmc]

I would just spend half that and get the (constant Pressure Valve body) that way you don't have to mess with the TV adjustment. It maintains the pressure internally.

 

Ditto!!!!!!!

[kc8oye]

{calmly} ok, I'm going to say this one last time.. perhaps then someone will listen to me... {/calmly}

 

the problem is not in my TV CABLE

 

The trans:

will not 1-2 upshift until 30mph. *period* throttle position does not matter.

will not 2-3 upshift until 40mph. *period* throtte position does not matter.

 

all part throttle upshifts are way to late

all full throttle upshifts are way to early.

(basicly, the shifts don't move in response to the TV cable)

 

the trans will not detent-downshift for any reason, regardless of TV cable

position.

 

the only upshift that seems to work correctly is the 3-4 upshift.

above 50mph, the trans will not 4-3 detent.

it will not 4-2 downshift for anyreason.

it will 3-2 downshift at low speeds (like around 30 mph)

I don't think it has ever made a 2-1 downshift either.

 

If the problem is TV related, it's inside the transmission's valve body.

I purposely over adjusted the tv cable to the point that it stopped me from being able to open the secondaries all the way.. and it still won't give me correct full throttle behavior, and my trans shop just keeps telling me I need to adjust the tv cable.

 

so in march when the warranty is up, I'm gonna put a new valve body in it. I dont' think it's gonna be full manual because the car is driven on the street and I don't want it screech-bang shifting all the time.

 

side note: I understand the 1-2 upshift will be late, that's actully what I want. partly because of my driving style, partly because 1st gear is so 'short' (3.06:1) with 3.55:1 rear gears, at _FULL_ throttle, I want the 1-2 upshift to happen very close to 6000 rpm to make full use of that 1st gear.

but when the PART throttle upshift doesn't happen until 30 mph, that's a problem, cuz that means I'm doing 4500 rpm @ 25mph in a residential area (which I do frequently going to mom's)

and going up to 30 is not a good idea

 

as for my driving style, I prefer to roll around the corner, and then lay into it.. mainly cuz with that posi, she likes to slide a lot. and that's not good when traffic is heavy and I'm trying to pull out into traffic.

 

[monte70car]

if anything they should tell you have to set it up. ive read alot of tims problems with his 700 and he has taken it back to the show but the owner keeps tell him its right. and you don't want to take it to another shop since it has a warranty. i would ask them how to set the tv cable up. i know bowtie overdrive wanted 200psi in each gear tv cable hooked and unhooked. since we are dealing with a holley carb the tv cable need to be off center of the throttle stud so it pulls right. holley sales the bracket that moves the tv stud back some. im not sure if you are running that bracket or the one that was on the carb when dave got it. it could be the trans is low on fluid. when my 700 was low on fluid it would shift odd even adjusting the tv cable would change when it shifted. you have changed the governor and it did not change anything right? with the governor you have to play around with the different parts in the kit.

[Heckeng]

I agree with Allan, I still think it could be TV adjustment. Like he said, that cable tells the tranny the throttle position which will change your shift points, and also adjusts the fluid pressure which would need to be higher at higher loads to keep the clutches from burning up.

 

If you have your TV cable too tight, the tranny will think you are under a large throttle opening situation and it will make the shift points later.

 

You are right to look at the governor too, if you have excess dirt or wear in the tranny (in this case in the gov bore), your gov may not be operating correctly. It can get stuck and not move right which will change shift points like you are describing.

[kc8oye]

I pulled the cable all the way out as far as it would go, and locked it in that place with a pair of essentially very small vice grips, and it still wouldn't upshift in the right place.

I can leave the cable unhooked, and it will still upshift very late at part throttle.

 

I should bave been a little more explicit, the problem is not in the adjustment of the tv cable. and yes, I've had the shop set it several times.

 

I would like the MVB.. but I don't want the trans screech-banging the shifts at part throttle when I'm just trying to roll around town.

 

[Heckeng]

The manual valve body will likely shift pretty similarly to your current valve body because at part throttle and moving around town you still have your torque converter absorbing the shocks.

 

I switched from a stock VB to an ATI competition VB because my old one was not operating properly. All in all, I can't really tell much difference between the ATI VB and my old one when it was working right. Both had similar upgrades to make the shift quicker etc.

 

The only drawback with the manual VB is that it is a manual VB! You will be shifting all the time!

[kc8oye]

I'm already doing that anyway scott.. might as well go all the way this trans has a habbit of forcing upshifts on me when I don't want them too. If I hang out @ 6000 rpm too long it will force a 1-2 upshift even when I'm in Low-1

 

[Sam (Bones)]

that means your governor is working

 

[kc8oye]

yeah i know sam.. and I don't like it.

that would be ok for a stock engine that wouldn't want to see the high side of 5000 rpm most of it's life.

I tend to get up arond 6k from time to time doing a burnout.. it's very annoying when the trans shifts to 2nd, cuz I don't just dont' have the torque to roast 'em in 2nd

 

[TimD]

Guys,  

I have a newly rebuilt 700r4 behind a 350 SBC.

When i adjust the TV cable to shift 1-2 at 20 mph it about snaps you neck off, 3-4 is tollerable.

So I tweeked the TV cable so it shifts 1-2 @ approx 12-15 Mph and 3-4 shifts @ approx 35 mph. This resulted in a softer and tollerable 1-2 shift. 

My question is will my clutch bands survive this earlier shifts?  I do have a good cooler out in the wheel well. 

Thanks for your opinions and suggestions.

Tim

[Scott S.]

Welcome to the site Timothy,

Yeah, those T.V. cables are a bear to set......

I'm curious as to what type of torque converter you're using, and to what level of "rebuild" you had done. What type of springs and such.

As for the cooler, I'd recommend one that gets better airflow, mounted in front of the radiator would be optimal. 

The shift into 4th gear (overdrive) seems pretty low, mine's closer to 55-60 mph. Going into overdrive to low can do damage to the bands, (lugging on the bands) or so my transmission guy says. 

Hope you figure it out, Scott.

[72 Monte Carlo]

ADJUSTMENTS

Before adjusting the TV cable, check the following:
1. Transmission oil level. Correct if necessary.
2. Proper engine operation. This can cause problems similar to a malfunctioning transmission.
3. Dragging brakes. This can cause detract from vehicle performance and cause transmission malfunction.
4. Check the TV cable to ensure that it is the right part for the vehicle.
5. Check the cable to ensure that it is properly connected at the transmission.

Adjustment procedure (self-adjusting cable)

1. Stop the engine.
2. Depress the adjusting tab and move the slider back through the fitting away from the carburetor until it stops.
3. Release the adjustment tab.
4. Move the throttle linkage to rest against the full throttle stop, then release it. (This method is tricky, if you're not getting full throttle valve opening via the throttle pedal - incorrect throttle cable adjustment. That's why I like to have an assistant depress the throttle pedal to the floor)
5. Check the cable to ensure that it is not sticking or binding.
6. Road test the vehicle.
7. If the problem still exists, refer to the cable diagnosis section.

This is from this website

https://cpttransmission.com/tech_tvcable.htm

[Jason72]

The TV cable on a 700 is not a kick down cable! If you treat it as such you can easily burn up the transmission. it’s designed to increase the transmission pressure in relation to the throttle position. 
 

The way to adjust shift rpm is with the springs and weights on the governor 
 

[Jason72]

https://www.summitracing.com/parts/bmm-20248?srsltid=AfmBOop3pTEZvVnYufzBBd2eDPHHx5vjPYnRNju6hcYMFcNhR2E8b8FL

[Leghome]

When I had to have my 700r4 rebuilt Frank just put it together and we took it out for a test drive and he stopped 3 or 4 times to adjust the cable so the shifting felt right. He has only been rebuilding trannys for 35 years so he does have some experience and it works flawlessly 

[Jason72]

Yes, the cable controls the throttle valve which controls the pressure during a shift based on engine load. The higher the pressure the harder and faster the shift. The time the shift takes can be perceived as raising or lowering the shift point. If the cable is too loose, the shift will be mushy and take longer to complete and if too loose, the pressure is too low and too much slipping happens while applying the clutch for the next gear. 
( I am a 35 year gm technician also)
 

[Scott S.]

The next question is..... Did you go with the "lock up" type torque converter ??? 

There are wiring kits available that are necessary for that as well. 

[Jason72]

[Jason72]

[Jason72]

[Montemedic]

Thank you for sharing this information Jason. 

[Jason72]

Like I said earlier, the governor controls when a shift happens. It “governs” engine speed. 
I have done tons of 700s in performance cars and plenty in trucks. 
my own car, when I first put it on the road shifted wot at 5000 rpm. After a cam and converter it still shifted at 5000 rpm. I changed the weights on the governor and got it to shift at 6800. 
 

a factory transmission behind a diesel shifted at 3500 rpm. 
if you took that governor out and put it in a corvette, the corvette would then shift at 3500.  
if you put the governor from the corvette into the diesel, it wouldn’t shift if over 1/2 throttle because the engine couldn’t reach the rpm needed to make the governor tell the shift to happen. 
 

in the tv valve description above, “timing and feel” is referring to how long the shift takes to complete. Not when it happens. 
 

the governor description, “speed signal for controlling shifts” refers to what rpm the shift happens. 
 

id have to do more digging , but, the outer weights control wot shift, inner weights- part throttle and springs influence down shift. If I recall correctly 

Edited May 1 by Jason72

[420ponies]

I don't remember having any trouble with my 2004r behind my 355/420hp sbc. I just was told to make sure the cable was extended all the way at full throttle. Shifted fine through all mph's and had a firm 1-2 shift (wouldn't break loose tires,I found out I had a 2:73 posi 10bolt) . 2-3rd was fine, overdrive at 55mph and I had a switch to turn on-off overdrive. That had a 2,200 rpm converter.