Just a quick question for all of you A604 experts...do I have to take the transmission out in order to change the valve body on this transmission or can I just go through the pan?

 

no you can just drop the pan, but why are you changing the valve body?

 

Well it doesn't go into overdrive, and I've changed the filter, fluid (with ATF+4 of course), torque converter, computer, and housing, and I was told that if the valve body wasn't changed in the transmission then that COULD potentially cause it not to shift properly. With that said....could you give me a brief how to on how to take the valve body off if at all possible

 

that's weird cuz the valve body doesn't do anything with gear shifting. i bet you have a switch problem with the od cancel switch or wiring related to it. using a quality scanner looking at tcm data would be benificial to solving this problem

if you got 1st, 2nd, 3rd but no OD then you got an electrical problem cuz 4th uses 1/2 the clutches for 3rd and 2nd. in the valve body theres only like 5 valves, 2 are for torque converter, one is a solenoid switch valve one is for pressue regulatr and the last is the manual valve so it knows forward, reverse and park/neutral

I'll bet your od prob is def in the cancel switch circuit stuff

 

Well before replacing it, I had the TCM scanned by AAMCO and they said it threw absolutely no codes, but let's just say there is a problem with the O/D switch, how could I trace the wiring and what could I replace in order to remedy my lack of overdrive?
And sidebar: Isn't the O/D switch wired into the reverse lights, so if I have reverse lights doesn't it mean that the switch is functioning? (Just something I remember reading)

 

The correct way to fix it is get a Factory Service Manual, wiring diagrams, real scanner for data access (codes are NOT the answer data is), a multimeter and some effort and you can fix the problem.

read the previous topic on this problem, do extra research, get the above mentioned tools/materials and you should be able to come to a solution.

internet instant gratification can only go so far, you'll need to actually test-diagnose-repair to solve the problem but I can assure you it's not the valve body as your problem

 

there are three wires on the O/d switch red= 12 volts
black feeds the tranny
yellow= light on dash o/d off

check for voltage on red no voltage check back up light fuse

 

Alright, I'll really be able to dig into it tomorrow and let you guys know what I come up with as far as the wiring. Thanks for all the input

 

One more quick question. In order to check the voltage on the wires, are they located near the shifter (underneath the console), or are they located on the transmission near the input sensor?

 

from what the man said, the OD switch which id think is on the shfiger. I don't know that it is anywhere near the transmission input speed sensor except the solenoid pack , i wouldnt think you's open the hood to push the OD button. i think it would make sense to check the wires at the switch on the shifter for these problems since it's really the only possible spot for you not to have a shift to overdrive based on all the stuff i've read on hear about O/D switch causing no overdrive but everthing else is working