Setting base TV with pressure gauge

V

VIN7

Member
Joined
May 24, 2001
My TV plunger spring is longer than stock so setting by the factory procedure raises idle TV pressure to around 110psi. This is no good since it doesn't allow the car to downshift back to first when coming to a stop. So what is the best way to set TV with by pressure. TV disconnected is about 75psi (needle bounces around), I have it set so it drops to about 80 psi, but any throttle input still causes instant rise. Is this OK?

Also, I burnt the band and replaced it. I cleaned as best I could but there is still some material in the pan after several oil changes. I think this is causing the 3-4 valve to hang (No OD), even though I have disassembled and cleaned the 3-4 valvetrain. Also the 2-3 part throttle needs me to back off the throttle for the shift to happen. The shifts were fine before the band fried. Any other valves that could be problematic for these symptoms?

Also, will applying air to the 4th pressure port act on the 3-4 valve to free it up?
 
It sounds like you are planning to drop the pan anyway, why not swap out the tv spring for a shorter one? doesn't even require VB removal.

If you loosen the tv cable to try to remedy the problem, the trans wont be able to "see" wot via the tv cable and thats a whole other can of worms. It needs to be set so it bottoms out the TV valve at WOT, no more, no less.

And based on the material still showing up in the pan, and no overdrive, you likely have other problems. Was that TV spring working prior to this?
 
Ok, it is set at idle so it just drops to 90 psi consistently (one more click tighter and sometimes it doesn't drop below 100 psi every time and I get second gear starts). Max TV is reached at about 40-60% throttle all the way to WOT.

I have all four gear ratios but...at part throttle the 1-2 is fine, the 2-3 and 3-4 will only shift if I lift the throttle. I'm thinking something in the gov circuit. Even at cruise if I manually shift back and forth between 3-4, after downshifting 4-3 and try to 3-4 I have to lift the throttle for the shift to occur. I haven't tried a WOT run yet.

Any ideas? This vb and gov used to shift on its own without lifting.
 
How far did you tear into it when the band was replaced? I don't suppose you measured the tv plunger spring
 
I just went far enough to get the drum out, didn't want to mess with the stack up below that. I air checked all the apply ports. Plunger spring is 2.0"

The reason the band burned was a torn lip seal on the servo, wouldn't allow the servo to kick off. All the other frictions looked new, maybe about 2000 miles on the trans when the band died.

Now I'm thinking tv limit may be sticky. I didn't take that one out to clean, I remember not removing any of the larger roll pins.
 
If I can suggest add an inline filter if you are still seeing anything in the pan. When my low roller clutch decided to lose some of its lining the pepper particles caused the 1-2 shift valve to stick, I developed a flair and burned up the band.

I cleaned and flushed everything and still found some particles enough to hang a valve (it doesn't take much). The inline filter fixed that for me. I have since replaced the filter with a new one and continue to run one, even added one to my daily driver.

I can get you part # if you'd like when I get home this evening, I installed it just before my trans cooler.

Jim
 
I think the inline filter is an excellent idea and would do that.

But if it shifted well before I would attribute it not shifting now to debris in the vb or gov circuits. If you are dropping the pan I would pull the vb and the governor out for a thorough cleaning. You say the tv spring is 2 inches but I know I used a 2.1" spring on the advice of one of the gurus from this site so I think your tv isn't returning to the at rest position.


My "custom" spring on top and the stock one on bottom

I put a spring in the "deep" end under the tv piston to force it back so the pressure got under 100psi. you might look at something like that. I found it at the hardware store where I got the tv spring though I'm sure sonnax or someone sells them.
 
Yeah, if I could get that inline filter part number I would appreciate it.

I thought I got a good measurement, but the plunger spring is whatever Lonnie is using now, could very well be 2.1 I'll measure more closely when I drop the vb. I'm actually using two springs for the return. A pen type spring in the valve and another spring the fits on the outside. I'm sure it is all the friction material floating around causing this grief.

Another question, does anyone know if the CZ uses a lighter spring for the 3-4 shift valve? I really like how it would shift to 4th under 45mph, drove around town better that way.
 
VIN7 said:
Yeah, if I could get that inline filter part number I would appreciate it.
Click to expand...

x2... I like this idea of an additional inline filter. What micron rating would be advisable for a filter from the trans to the cooler? Most of Peterson oil filters are 60, 80, 100 micron...probably go with one of theirs. Will a finer filter be too much of a restriction?

Thanks for the help, Rob
 
on the TV geometry, you can shorten the travel of the arm on the throttle body by bending it down slightly. I tuned the idle point on my old car that way.

B
 
VIN7 said:
Yeah, if I could get that inline filter part number I would appreciate it.

I thought I got a good measurement, but the plunger spring is whatever Lonnie is using now, could very well be 2.1 I'll measure more closely when I drop the vb. I'm actually using two springs for the return. A pen type spring in the valve and another spring the fits on the outside. I'm sure it is all the friction material floating around causing this grief.

Another question, does anyone know if the CZ uses a lighter spring for the 3-4 shift valve? I really like how it would shift to 4th under 45mph, drove around town better that way.
Click to expand...

It's WIX 58964 and has 5/16 inlet and outlet.
 
I went with a Magnafilter with 3/8" ends.

Cleaned the vb, especially the TV limit valve, still need to slightly lift to get 2-3 and 3-4 part throttle shifts. Just going to drive it and maybe it will free up. It used to shift with no problem.

Note: I swapped a CZ 3-4 shift spring into the BR3 vb and success. I can get 40mph 3-4 shifts which makes cruising around town much nicer.
 
Just to add updated findings.

It WILL shift the 2-3 by itself with moderate throttle @4200 rpm. I have the CZ gov that I've trimmed the small weight the same as the BR gov small weight. I air tested the CZ and it seals with the balls seated. The Larger weight looks bigger on the CZ, I'll weigh it when I swap. I'll also take a look at the BR gov sealing ring, maybe it is leaking gov signal oil???
 
While you are weighing could you weigh all the weights on the br and the cz gov. Good info to have. Thanks.

Sent from my HTC PH39100 using Tapatalk
 
Turns out that the gov weights used with the CZ (in my particular application) had been modded to mimic a BR gov. I did swap gov shafts to the one with the red sealing ring vs. the original black.

Same thing, have to lift to get a part throttle 2-3, and 3-4. However, WOT will shift the 2-3???
 
Ok, since it shifted the 2-3 at WOT I figured the gov circuit was ok so I looked at the other side of the shift valves, the TV system. I replaced the (bottom in pic) TV plunger, bushing, and spring (2.1") with the original (top in pic) BR setup and spring (1.9"). Now the car shifts quick and firm on its own at part throttle. FIXED. I may shim the spring since there is some slack in the plunger before it touches the spring, but going to drive it for now instead of looking at it parked in the garage.

tv plunger.jpg
 
That's why I bought mine, so I could drive it. Glad you are making headway.

Sent from my HTC PH39100 using Tapatalk
 
VIN7 said:
Ok, since it shifted the 2-3 at WOT I figured the gov circuit was ok so I looked at the other side of the shift valves, the TV system. I replaced the (bottom in pic) TV plunger, bushing, and spring (2.1") with the original (top in pic) BR setup and spring (1.9"). Now the car shifts quick and firm on its own at part throttle. FIXED. I may shim the spring since there is some slack in the plunger before it touches the spring, but going to drive it for now instead of looking at it parked in the garage.
Click to expand...

If you shim the spring that will increase the line pressure at idle. I just went through this ordeal with my car. The trans with the TV cable adjusted correctly would shift very late and very hard. Had to back off the TV adjustment to get the trans to shift somewhat decent, but still had very high line pressure with no throttle opening (idle).

Found the springs used for the TV plunger & TV valve were all wrong.

Next time the pan is down measure the length of plunger that is protruding from the face of the bushing. With a properly adjusted TV cable it is 0.668" in this particular vehicle. This is at idle, which can vary due to the idle setting of the throttle body stop screw. This has the plunger already depressed some, which is why a shim will increase line pressure at idle.

If anyone is interested I can go into the details of how I finally setup the TV springs (plunger and valve).

RemoveBeforeFlight
 
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