2004R 1-2 shift point low

[TPI83]

My unit has just been rebuilt. The shift point is 5 to 7 MPH. I understand that the spring is incorrect and need a heavier one. I haven't taken a pressure reading yet. To have the 1-2 shift at 15-20 what pressure would be correct? Or what would be the correct dimension of the spring to use? Would going by a color on the spring help in selecting the proper shift point? All other shift points are good and the TV cable is set correctly. Just as a test I readjusted the cable by one and two clicks and it still shifts out at 5-7.

 

[77 cruiser]

Does it have 2 springs on the gov.?

 

[TPI83]

Yes it has both springs. These are the Min/Max pressure readings I got yesterday, trans was at operating temperature, TV cable adjusted correctly and it's a CZF trans.
P 75/190
R 120/160
N 75/190
D 75/170
3 75/170
2 175/160
1 160/150

 

[SSedan64]

Pressures are a little odd & low.
Have you checked/inspected the Pressure Reg., TV Boost, Low/Reverse Boost valvetrain?
Some Pr. Info:
http://www.extremeautomatics.com/techinfo.html
http://www.jakesperformance.com/TV_Cable_Setup_Info.html

 

[77 cruiser]

Take the spring off the big weight. Your pressure is a bit low. What rpm did you test at? Try about 1500.

 

[TPI83]

Pressures are a little odd & low.
Have you checked/inspected the Pressure Reg., TV Boost, Low/Reverse Boost valvetrain?

No I haven't done any of this yet. I'm going to give these pressure readings to the person who did my tranny and see if he will correct the pressure problem. If he won't it looks like it's up to me to find/repair the problem. Of the three area's you want inspected which one would be more likely to give me the low 1-2 shift point? I did all the pressure checks at 1000 rpm also. Should it have been tested higher?

 

[SSedan64]

Checking the Pr. Reg & Boost valves was to see why the 1st & 2nd gear Pr. readings were so strange & low.
1000-1200rpm is normal range for checking Pr. Try checking @1500rpm to see if anything changes.
What are you working with?:
Carb, EFI, brand ?
Style/brand of TV cable brackets?
Rear Gear ratio?

 

[TPI83]

I looked at the pressures again and reverse is low for the high side. Thought maybe the low/reverse boost valve could be a problem. I have a 91 TPI (OEM) with factory brackets, 86 CZF trans and 86 3.73 rear, all in a 83 Monte Carlo. I just came back from the rebuilder and he wants to put a lighter spring in the 1-2 valve to make it shift later. I thought a heavier spring would do that. He didn't tell me the reprogram kit he's using (says it's his own). With a .500 TV boost valve shouldn't all the high pressures be higher? Also a 10 vain pump was installed. I'll let him do the spring change and retest at 1500 when I get it back.

 

[TPI83]

Got the car back, the rebuilder says he changed one spring in the governor (lighter). Unit now shifts 1-2 at 15 mph all other shift points remain the same. Here is the pressure readings after the change. All done at 1100 RPM. Had done test at 1500 RPM but pressures were about the same also.
P 75/200
R 125/235
N 75/200
D 80/200
3 80/200
2 220/230
1 220/230
Can't see how the governor could make this happen. From what I've read the governor only effects WOT shifts. I would think the low/reverse boost valve would up the pressures for 1,2 and reverse.

 

[Ttype6]

Got the car back, the rebuilder says he changed one spring in the governor (lighter). Unit now shifts 1-2 at 15 mph all other shift points remain the same. Here is the pressure readings after the change. All done at 1100 RPM. Had done test at 1500 RPM but pressures were about the same also.
P 75/200
R 125/235
N 75/200
D 80/200
3 80/200
2 220/230
1 220/230
Can't see how the governor could make this happen. From what I've read the governor only effects WOT shifts. I would think the low/reverse boost valve would up the pressures for 1,2 and reverse.

The line bias valve spring is the big player in your max pressures. Stiffer spring=higher max pressure. The major player in WOT shift point is TV limit valve spring. Stiffer spring=higher WOT shift point. It will also down shift easier/sooner with less throttle movement. Lighter governor spring will increase shift points all across the throttle range. Your numbers all look good now. If you like the way it shifts and you are happy with when it shifts and the quality of the shifts,leave it alone.

 

[TPI83]

Why does a place like Jakes Performance and Extreme Automatics post higher pressures for P,N,D and 3? Where would be the point when higher pressure is at a good or passable point? Also was the low/reverse boost valve changed to get the increase in pressure from original readings?

 

[Ttype6]

Why does a place like Jakes Performance and Extreme Automatics post higher pressures for P,N,D and 3? Where would be the point when higher pressure is at a good or passable point? Also was the low/reverse boost valve changed to get the increase in pressure from original readings?

Again,the line bias valve spring pressure is responsible for max pressure. It must have been changed unless they found some other mistake. The lighter governor spring is what changed your minimum and light throttle shift points.
The higher max pressures you read about are beneficial as engine power output is increased. If you want to increase it put a spring with much higher tension in with the line bias valve. Doing this will increase all of your max pressures,but you're good where you are.

 

[TPI83]

Ttype6 thanks for your answers to my questions. Being my engine doesn't have high HP numbers I can see now that the pressures will be OK for my application.

 

[quickt]

Why does a place like Jakes Performance and Extreme Automatics post higher pressures for P,N,D and 3? Where would be the point when higher pressure is at a good or passable point? Also was the low/reverse boost valve changed to get the increase in pressure from original readings?

I am not quite sure I under stand the question about passable point.

The Reverse boost Valve only affects Reverse Pressure and Manual 1-2 Pressure. The Pressure Regulator spring affects all pressure in every gear. Based on the pressure listed I would say the PR spring was replaced.

 

[TPI83]

Lonnie what I mean as passable is, my pressure on the hi side for P,N,D and 3 are low for your specs but by what Ttype6 says I'm OK because of the HP my engine makes (let's say about 350). So making 200 vs 230 is still in the ballpark for a unit to last.

 

[quickt]

Lonnie what I mean as passable is, my pressure on the hi side for P,N,D and 3 are low for your specs but by what Ttype6 says I'm OK because of the HP my engine makes (let's say about 350). So making 200 vs 230 is still in the ballpark for a unit to last.

I would agree that some units can live at 200. I still think that is a little low for any car that might see low 12s hi 11s.

I build units to last the customer and back it with a warranty. So yes I will always error on the Hi side. If your transmission makes the full power WOT shifts with no slipping your all good. You just have no room to grow with any additional power.

 

[Ttype6]

Based on the pressure listed I would say the PR spring was replaced.

If you take another look at his before and after pressure readings you'll see that idle pressures stayed the same. Idle pressures would have increase if a stronger pressure regulator spring was installed.

 

[quickt]

If you take another look at his before and after pressure readings you'll see that idle pressures stayed the same. Idle pressures would have increase if a stronger pressure regulator spring was installed.

That would only be correct if we were to assume the spring rate was increased with the same install height as the original spring. I would compare the white 7004R spring with the pink 700R4GM spring. White spring about 200psi pink spring 230psi idle will be same or within 5 psi either spring. One spring 2" other 2.18 free length. What other spring affects Max pressure with no change to non boosted pressure? Comparing the before and after listed its clear to me there was a change of about what I would expect to see from a PR spring change. The non boosted pressure where it counts bumped 5 psi. Largest difference indicating PR spring is in manual 1-2. Manual 1-2 boost is a direct fluid to the reverse boost valve and PR spring only. That removes TV limit, TV spring and anything with the VB. Yet we have pressure increase. The PR spring is the only spring in the transmission that will increase manual 1-2 pressure. One thing is for sure. The Gov spring most certainly wont increase main line pressure.


P 75/190
R 120/160
N 75/190
D 75/170
3 75/170
2 175/160
1 160/150


P 75/200
R 125/235
N 75/200
D 80/200
3 80/200
2 220/230
1 220/230

 

[Ttype6]

That would only be correct if we were to assume the spring rate was increased with the same install height as the original spring. I would compare the white 7004R spring with the pink 700R4GM spring. White spring about 200psi pink spring 230psi idle will be same or within 5 psi either spring. One spring 2" other 2.18 free length. What other spring affects Max pressure with no change to non boosted pressure? Comparing the before and after listed its clear to me there was a change of about what I would expect to see from a PR spring change. The non boosted pressure where it counts bumped 5 psi. Largest difference indicating PR spring is in manual 1-2. Manual 1-2 boost is a direct fluid to the reverse boost valve and PR spring only. That removes TV limit, TV spring and anything with the VB. Yet we have pressure increase. The PR spring is the only spring in the transmission that will increase manual 1-2 pressure. One thing is for sure. The Gov spring most certainly wont increase main line pressure.


P 75/190
R 120/160
N 75/190
D 75/170
3 75/170
2 175/160
1 160/150


P 75/200
R 125/235
N 75/200
D 80/200
3 80/200
2 220/230
1 220/230

I stopped looking at the pressures after noting the first three. I see the manual 1-2 rise now. I agree.

 

[TPI83]

So what would you do to increase just the P,N,D,3 high pressures to say 230?