Excessive Pressure

[Mad_Trbo]

Trying to make sure I do everything correct.

I recently went to a Monte Carlo SS valve body, Art Carr torque converter Non l/u. I was checking the tranny pressure through the 1/8npt fitting on the drivers side of the transmission.

@ 1000 rpm the needle kind of shutter back and forth quickly, if I idle it around 1300 rpm the needle steadies out.

I noted pressure = 220 psi minimum throttle position. As I remained stationary and moved through the gear selection the pressure did not change. In other words P/R/N/OD/D/3/2/1 all read the same pressure. Stuck TV valve, I don't think so. I feel spring tension when I pull on the T.V. cable.

Other symptoms are it shifts into 2nd gear but won't down shift @ WOT or even when stopped completely. I have to manually shift it back to 1st. Final symptom is prior to chages, when I shifted into reverse you knew it. You could feel it shift, now it really isn't noticeable. In fact you wouldn't know until you took your foot off of the brake.

1st question, will these excessive pressures hurt the tranny?

2nd question any idea what might cause this, looking for a more specific answer.

I have the CK manual and note possible causes as follows;l

tv cable adjustment
pressure regulator valve
tv boost valve
reverse itnermediate boost valve
tv plunger
throttle valve
tv lmit valve
line bias valve
spacer plates

have any of you had my symptom and found it to be related specifically to one of the listed above. I seriously don't think it is a stuck TV valve.

Thanks

 

[jakeshoe]

The TV valve is not the same as the plunger. So the TV can be stuck in the full TV position and the plunger in the minimal position. You will feel the plunger pushing the spring even with a stuck TV valve.

Start the vehicle, and pull full tv on the cable, have some shift from drive to reverse a few times, and then let of TV and do the same.

 

[Mad_Trbo]

Specifics on help please

Ok guys I could really use some real diagnostic help.

I'll try the procedure described in the previous thread, but I need to know is there anyway to isolate what the problem is.

How can I definitively determine if my issue is a stuck throttle valve vs a pressure regulator valve or any other issue?

If it turns out to be a stuck throttle valve, how can I definitively fix this. Do I need to pull the pan off and then if I pull the pan do I need to pull the valve body?

Finally can the car be driven like it is or will it damage the transmission?

I think I did a decent job listing the symptoms, if more information is needed please let me know.

 

[Lee Thompson]

No expert but,

Like Jakeshoe said it is probably the small inner spool in the tv stackup that is stuck--try this, disconnect the tv cable @ the TB and pull to full extension and let snap back --do this a few time it may or may not unstick the plunger. Since you have the CK manual you can se how the stackup goes. Don't believe you can fix without removing the VB. You will know if it frees up as your pressure will drop to 90 PSI @ min.TV
BTW, I do know that it will start out in second gear with high min. tv.

 

[Mad_Trbo]

Soft & early part throttle shifts

Well it did turn out to be the TV valve, oddly or not so oddly it was stuck. I don't understand why that happened but it did and I've learned.

Now to my next challenge the shifts seem really soft and quick at part throttle.

Unfortunately I don't have a stock TV cable, I have a universal deal and it is set such that at idle I see 90 PSI of pressure. But I am still seeing early and soft part throttle shifts.

Shouldn't even part throttle shifts be firm? Where should I be looking? Thanks!