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  #16 (permalink)  
Old 02-05-2005, 11:45 AM
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Do not move the TV cable toward the the carb more than 1 or 2 nothces/clicks. Your understaning of TV cable function is correct. The cable must botton the plunger at WOT. If you change the cable tension (less) then engine torque moves ahead of pressure rise (the result of TV cable input) and clutches burn. Too much movement of the cable and you will lose detent (kickdown).
If you move TV cable check for 2-1 detent after the trans upshifts 1-2 at minimum throttle (drive like a grandma). Low speed upshift 1-2 is usually under 10 MPH. If you have no 2-1 kickdown, tighten cable adjustment until you get it back. This test can be done in very short test drive. Once you know cable is set right, leave it alone and change upshift timing with the governor springs. Don't be afraid to add spring weight there.

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  #17 (permalink)  
Old 02-05-2005, 12:06 PM
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Cool

Since the line bias valve is blocked and there is a .500 boost valve , the line rise should react very quickly.

I'd back off the TV adjustment very little and test as Chazmac suggests.

Real Light throttle shifts usually are altered more by spring changes than weights. Weights come more into play above 35 mph , but this all varies with tire / rear gear ratio.
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Old 02-05-2005, 12:23 PM
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The line bias is not blocked anymore. This was my first suspicion for the problem so I removed the blocking pin.

One thing I thought about is that maybe some burned clutch material blocks the channel where the small governor screen is installed.
I didn't check that screen when I changed the clutches. Maybe only at WOT the pressure is so high that the debris blocks the flow in this passage. At lower trhottle settings enough fluid can pass the screen. Just a thought.

I can't believe anymore that the problem is the high pressure by the .500 boost valve. There are hundreds of people with the same mods that seem to have no problems.
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Old 02-07-2005, 01:08 PM
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Hey guys,

I've performed the procedure Chazmac suggested, but it didn't help with WOT shifting.
I changed to lighter governor springs for better wider stacked upshifts at part throttle though.

The tranny still won't upshift at WOT.

What else could be the reason for that. I will try to get another governor but I guess without buying one its not going to happen.
In germany the prices for such parts are crazy.

I know that I have no spectacular news but this malfunction still bothers me alot. I can't go to the track, because I will have the get off the gas between shifts. Please help me with this.

Thanks Alex
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Old 02-07-2005, 01:26 PM
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I'm sorry, I NEVER looked at your location!!

Lets get a little more technical:
Install a 0-300 psi gauge in the port above the shifter linkage (7/16 head, 1/8" pipe thread).
Start the car and note the idle pressure in all ranges.
Check WOT pressure by pulling on the TV cable ferrule (the part that is crimped to the end of the cable). Make sure that it is pulled fully. Use Vise Grips or similar, there will be a lot of tension.
Note the pressures in all ranges. Be careful in reverse, don't let the gauge go past its stop.
I would like to see ALL range readings.
Also, do what I call a sweep test in OD or D.
Start from idle and watch the gauge as you pull the cable to WOT.
Let me know if the pressure rise (sweep) changes as the cable is pulled.

These tests do not need more than engine idle speed to check.
BE sure someone is in the car with their foot on the brake pedal HARD! Do not get run over.
Your gauge has to read at least 300 psi max or more. Higher than 600 psi max and we won't get enough scale. Be as accurate as you can. A new(er) gauge is better.
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Old 02-14-2005, 05:37 AM
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Alright guys, I'm back with some results from a pressure test.

Unfortunately I couldn't find a 300psi gauge. I had to work with a 175psi gauge.

Pressures observed at idle (650rpm)

P 90
R 140
N 90
OD 90
D 90
L2 140
L1 140

Pressures observed at 1000 rpm

P 90
R 145
N 90
OD 100
D 100
L2 gauge went from 165 to 140 to 130 for 3 different tests
L1 gauge went from 165 to 140 to 130 for 3 different tests (maybe not fully heated fluid?)


I also performed the test Chazmac suggested.
I had the car in P and disconnected the TV ferrule from the carb.
The pressure went to 85 psi. The pressure rose (sp?) when I pulled the cable. It went to 170psi right before WOT and fell down to 130 at WOT!!! I tried this a couple of times. Always the same. With raised engine speed the pressure pegged out the gauge.

Since I was alone I could not test it in OD or D. I will try to get these numbers today.

The pressures in L1 and L2 seem too low to me. My book says it should be between 160 and 190 psi. Also the P,N,D,OD,and R pressures were higher than the book said. Is this the .500 boost valve?

The gauge needle was still in all ranges, but L1 and L2.

Also another thing that came to my mind. Like I said before I used a Transgo TV valve . They also supplied another spring which was shorter than the original. I left the original spring in because the instruction said so. Could the long spring push the TV too far?

I guess thats not how it should be.

Any ideas?

Alex
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  #22 (permalink)  
Old 02-14-2005, 07:04 AM
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OK, I just came up from the garage after making additional tests in all ranges. This time I had a second person brake and hold the gas while I was pulling the TV cable and read the gauge.
BTW, I had now a 350 PSI gauge for checking. I also checked the other gauge I was using. Both showed the same pressures.

I guess my transmission is in serious trouble. Look at this.

TV cable disconnected, engine speed 1000rpm

P 60
R 100
N 65
OD 70
D 70
L2 90
L1 75

TV cable fully pulled, engine speed 1000rpm

P 90 at 3/4 TV pull 160
R 160 at 3/4 TV pull 130
N 160
OD 85 at 1/2 TV pull 110
D 85 at 3/4 TV pull 95
L2 80
L1 70


I'm not sure why the pressure doesn't rise in some ranges. Thats where you come into play to help me out.
I hope that the new clutches aren't burned up again during my WOT tests on the road.

Please help me find the problems in this tranny.

Thanks
Alex
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  #23 (permalink)  
Old 02-14-2005, 07:24 AM
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By the looks of the pressure test you will have to get back into the VB.
You did match separator plate gaskets!
Try a different VB if you can find one or go back to square one with this one.
Try the shorter spring in the tv circuit. I have installed some kits following the directions and they must have been translated from some unknown language.

At this point you may be better off yanking the sucker and go right through it.
Just be sure you clean the cooler and lines real good.
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  #24 (permalink)  
Old 02-14-2005, 09:22 AM
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I suspect that there are a couple of problems.
First, the Pressure Regulator valve is causing some of the drop due to the second land being ground off. I know the kit said to do it, but my dyno tests have shown that this IS the result of the ground off land. I accept no more than .040" removed from this valve at the second land.
Secondly, I suspect that there is probably one ( or more) checkballs misplaced or missing. I am suspicious that the case checkball near the servo is not there. This ball is used for D3/detent oil. This indication is from the gauge reading.
Procedure:
Remove the pan. If the pan has black sediment or smells like charcoal, pull the trans, something is burnt.
Remove the valvebody and separator plate. Verify checkball location. An easy test: if there are two holes in the plate over a checkball SLOT or BATHTUB passage, the passage requires a checkball. Check all bathtub locations. Lay gaskets on plate and ensure that no holes are covered by gasket material. Check that the gaskets are installed correctly. The "C" stamped gasket goes on the case, "VB" or "V" for valvebody side. GM did have some cases which required the later, auxiliary valvebody gaskets to be installed even tho the trans had no aux VB. Double check the gasket passages against the case. Also these trans will have a separator plate that is diffferent. The gaskets will cover holes in the plate.
Remove the pressure regulator assembly and replace the valve with a new or unmodified one. The PR valve must have a hole drilled in the end. NO SOLID VALVES!
Good luck. Keep us informed.
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  #25 (permalink)  
Old 02-14-2005, 10:53 AM
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stu and Chazmac, thanks for the responses.

I placed the checkball after the Transgo instructions.
In the case I have 2 CBs that are in the middle of the case and very close together. I didn't install a CB near the 2-4 servo on the driverside because the instructions said not when the plate has only one hole there. My has only one hole. The trans is from1991.
There is also one CB next to the 2nd Accumulator installed in the case. The fourth ball in the case is where the TV system goes. Not in the round bathtub but under it.

The valvebody got only 2 CBs in the only 2 bathtubs. The elongated bathtub did not get one, because the plate has only one hole.

I tell you this from my mind and with the help of the transgo instruction. I'm pretty sure thats the way it is right now. I checked it a couple of times.
The Aux valvebody also got its CB.

The gasket should never cover any hole in the plate, right?

Also where exactly should be a hole in the pressure valve. Is it there from the factory or do I have do drill it.
Do you mean 0.040 from the diameter of the land?

Thanks
Alex
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  #26 (permalink)  
Old 02-14-2005, 12:11 PM
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I use 700 Pressure regulator valves unmodified. The hole is made at the factory and can be seen at the head of the valve.
A 1991 case should have 4 checkballs installed. 2 close together near the center of the case, one near the 4th accumulator bore, one in a bathtub passage under TV system. There is also a large round checkball location at the TV plunger end of the case that is usually left empty. This locatiion is at the edge of the valve body area. The bathtub location is underneath where the TV valve actually works and is about 1 inch long. There must be a ball at this location
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  #27 (permalink)  
Old 02-14-2005, 12:49 PM
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Chazmac,

Im pretty sure I installed the checkballs correct exacty where you describe.
I will open it up tomorrow and let you know what I found.
Do you have a partnumber for a new pressure valve?

Thanks Alex
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  #28 (permalink)  
Old 02-14-2005, 02:37 PM
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Sonnax Industries makes a replacement valve Part # 77754-04K.
I do not know if they distribute in Europe directly.
Try Transtar Industries. I know they have international distribution. Try www.transtarindustries.com for info.
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Old 02-15-2005, 06:47 AM
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Today I opened the tranny and pulled the valvebody and the boost valve withe the pressure regulator.

All checkballs were in the correct position.

Two CBs in the valvebody in their bathtubs. Four CBs in the case in the right spots.
I also checked the governor and converter filter screens, both were clean.

I also checked all valves in the valvebody for sticking, all were moving free.

The only mistake I could find besides the ground land on the pressure valve was, that both valve body plate gaskets had a "V" on them.
I took the remaining gaskets from my rebuild kit and found two different "C" gaskets. Ive put the C on the case side and the V on the valvebody side.

I checked the plate to see if any holes were covered. Neither with the V and C gasket or with two V gaskets any holes in the plate were covered.

So I guess this cant be the reason for the misfunction.

Do you have a GM part number for the pressure valve? I`ve found a number for an updated GM version, where the land is also ground away. Its 8684048

Please check this rebuild manual that I found
http://www.syty.huryde.com/html/tran...%20Rebuild.pdf


The pressure valve can be seen on page 21.


Im really confused now because I cant see any mistakes beside the wrong gasket.

Please help,
Alex
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  #30 (permalink)  
Old 02-15-2005, 06:50 AM
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If you had wrong gaskets that will cause all sorts of problems.
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