...in any way OTHER than through the EPC solenoid? My local tranny shop just installed a TransGo vac mod kit, yet the tranny is slipping on every upshift. My feeling is that the guy may not have installed the vac mod kit correctly as slipping in all gears probably points to low line pressure across the board. I just need to know if the EPC solenoid, which is bypassed/pacified with the vac mod kit, is the only point of line pressure control via the PCM. In other words, if the EPC is removed from the equation, is there any other manner by which the PCM could control/effect line pressure?

 

No.
The only other pcm controlled parts in the trans are the three shift solenoids and the tcc solenoid.

I have the kit waiting for me to install it and when I do I am going to install a pressure gauge before I even start the car, then I will apply and take away vacuum to verify line pressure response.

IMO I wouldn't drive the car until it's fixed, it may already be too late.

 

Hmm.. I'm certainly no expert, but isn't there is a solenoid that controls line pressure also? It's the one we remove when we add a vacuum modulator kit.

 

You need to read the top post again.

 

Anyone else?

 

According to Dave at Rock-On, there are several factors that determine the applied line pressure of a transmission. Some of them include the MAF, MAP, IAT, etc. The vac mod kit eliminates all of the guesswork, though the PCM still thinks it's controlling line rise and such.

If you're slipping through all the gears like you say, then the vac mod kit was not setup correctly. There have been many posts here recently about whether or not the vac mod kit is plug and play or an easy install. I'd say your trans shop may not have had that much experience with vac mod conversions.

 

I think that is where the problem lies...in the install. The tranny tech has never installed one before mine. I have some things to discuss with him next week. Thanks for the feedback.

 

Dooh, your right