Easy way to check trans line pressure

[Garys1969RR]

Checked line pressure on my 727, using my in dash oil pressure gauge, and a few pipe fittings. Worked great! Just so happens that the port on the tranny is 1/8 pipe, same as the oil pressure port off the engine. So I removed the gauge sending unit, and hooked a 3" pipe to the port on the tranny,an elbow, then a 6" pipe and another elbow. Screwed the sending unit into the elbow, hooked the wire to it, and the other end of the wire to the gauge. Worked great. By the way I'm getting 55 at idle, and 88 with the kickdown pulled back all the way. I think it's too low, so I'll be raising it......Also put a plug in the oil pressure port on the engine

 

[rumblefish360]

What does the FSM say it should be?

 

[Aeronet]

 

[Garys1969RR]

Thanks! That helps. It looks I'm within FSM limits. The problem I'm having, is that it is shifting out of first at 4000 RPM, and out of second at 4500 RPM. I put a 5600 RPM governor in, which Raised the 2/3 up shift 500 RPM. So now I'm going to put in a stronger spring for the 1-2 shift valve, and a stronger spring to raise the line pressure and see if that helps.

 

[Aeronet]

Do you have a manual valve body or a transbrake? The pressure values change if so.

 

[Garys1969RR]

No, all stock from a 1977 RV. It shifts real good and firm, even chirps the tires on the 1-2 shift. Just shifts way too early, the engine is just getting into its power range

 

[Aeronet]

Shifting early at full throttle?

 

[Garys1969RR]

Shifting early at full throttle?

Yes, and the the kickdown adjustment is adjusted all the way back, so at wide open throttle, it is at the end of its travel

 

[Aeronet]

Sticking governor?

 

[Garys1969RR]

It was shifting at 4100 RPM, so I put a 5600 RPM governor in it, now it's shifting from 2nd to 3rd at 4500 RPM. Shifting out of first at 4000

 

[Garys1969RR]

I ordered a high pressure spring from A& A Transmissions, to raise the line pressure. That should help increase shift RPM. Plus I ordered the white and red spring kit, the white one raises the 1-2 shift 500 RPM, and red one raises it a thousand.

 

[Aeronet]

 

[Aeronet]

Hope that helps.

 

[Garys1969RR]

Yes, it does! Do you have line pressure values for the 440 and 727 Trans, at full throttle, wide open?

 

[rumblefish360]

What is model 150 or 250?

 

[Garys1969RR]

What is model 150 or 250?

What do you mean? Where is the model # located, I'll check.

 

[Aeronet]

 

[Garys1969RR]

Hope that helps.

Say, do you know how to adjust throttle pressure? It says incorrect throttle pressure should be suspected, if the transmission shifts too early or too late. And this one is Shifting too early, under wide open throttle. Does that manual tell how to adjust throttle pressure?

 

[rumblefish360]

What do you mean? Where is the model # located, I'll check.

In aeronet’s post #12, the first picture, it shows engine displacement across the top line then under it is where my question came from where it says “model” with two choices of 150 & 250.

What do these numbers represent?

Say, do you know how to adjust throttle pressure? It says incorrect throttle pressure should be suspected, if the transmission shifts too early or too late. And this one is Shifting too early, under wide open throttle. Does that manual tell how to adjust throttle pressure?

I’d guess the manual would say where to adjust it but I’ll tell you when the pan is down on the drivers side forwards is a s few that when turned counter clockwise it will increase the pressure. Shifting early is lack of pressure and shifting late is excessive pressure.

I discovered this after installing a MP shift improved kit and gears in the rear end. Everything was way off. The MP deep trans pan was a huge help for quick drainage of the trans fluid. I had to do it a number of times to get it where I liked it.

 

[andyf]

If you had a Sniper fuel injection system then you could just install pressure sensors on the trans and data log the line pressure as you drive. Then you can see the line pressure on a graph along with RPM and everything else.