Pressure Switch Module

[zachw677]

I am looking into replace the pressure switch module on my Allison 5 speed. I went to Oreilley's and they tried selling me a PSM that only had 5 switches. It should have 6 switches right? Or 4 if it's an updated one?

 

[clrussell]

Don't buy one from parts store.. Get a gm or allison

 

[greendury]

Pressure switch manifold. Some of the switches were not used on the earlier black manifolds. They did away with them on the later blue manifolds

 

[Mike L.]

The Allison only uses 4 switches. The PSM was borrowed from a 4T45E trans and has up to 6 or 7 switches and it doesn't matter as the Allison only needs 4.

 

[THEFERMANATOR]

Buy it from ALLISON, it'll probably he cheaper, and a better part.

 

[zachw677]

Thanks guys! Got one ordered today through work. Hopefully this fixes the no movement problem I have.

 

[Mike L.]

Thanks guys! Got one ordered today through work. Hopefully this fixes the no movement problem I have.

I doubt it will fix it.

 

[zachw677]

What do you think the problem is Mike? Mechanic doesn't seem to know anything.

 

[Mike L.]

What do you think the problem is Mike? Mechanic doesn't seem to know anything.

I would have check voltage to the trans first. If you don't have 12V to the trim solenoids they cannot deliver pressure. Plugged sump filter is another thing. Not knowing the history of the trans, I can't say.

 

[zachw677]

According to the guy, he said he's checked every connection to the transmission and the ignition switch. He said he manually tried grounding the switch for P0843 and still nothing. Line pressure is great. The truck has been serviced by GM its whole life until I got it because it was a fleet truck for a window company. Odometer is on 264k miles. I'm going to have him replace the internal filter and PSM tomorrow. I accidentally slit a few of the wires that come into the firewall by the hydrobooster. Drove it two weeks after before this happened. Could this have anything to do with the TCM acting up?