Transmission operating pressures

[Sabrewings]

I was wondering if anyone knew the operating pressures of the tranny? I know we can program in the PCM up to about 96 PSI, but in my GM SI manual it says during the pressure check it could see as much as 240 PSI depending on how many amps you command to the pressure solenoid.

I'm trying to pick for a gauge and need to know the range I'm looking at during normal driving.

 

[Trannyman95]

You need a transmission pressure gauge that reads up to 300 PSI. The 96 psi parameter is just a BS number for the pcm to work with and has nothing to do with the real pressure inside the trans.

 

[JJ91284]

I spoke with the Engineers from GM racing inquiring about why the torsen diffs in our apps have issues with the planetary gears washers seizing. They told me in high hp street/strip setups, when you let off the gas at say the end of the 1/4 mile, the trans drops line pressure and the first thing to get reduced flow is the diff area. He said there is a specific amount of time the trans keeps the pressure up when you let off, but sometimes it's not enough in 10' sec cars or what not. In GM's racing 4t65e, he said they command line pressure to 300 psi to prevent that from happening as well as a few other issues.

On page 16 it talks about it a little

http://tunersource.gmblogs.com/Race...book/104742-enginehandbook_04racemodtrans.pdf

 

[Sabrewings]

300 PSI huh? Whelp, there goes the idea for a tranny pressure gauge (becomes quite expensive...). :th_shakinghead2:

Back to the drawing board.

Thanks, Trannyman.