TCU Diagram
 

Okey Dokey, guys. You asked for it, you got it . . . (no, I'm not gonna say the "T" word :) )

Here's a diagram of the TCU

solenoid pack
 

:confused:
Randy,
I was considering having the solenoid pack replaced last week, $229 for parts, tech said no.
The pack consists of 4 solenoids, why are more shown in the spec sheet? :confused:

Re: solenoid pack
 

Well, probably because there are SIX. :D As shown in the diagram there are three shift solenoids and three duty solenoids.

I had my hands on the solenoid pack last week, 2 shift, 1 lock up,1 fluid pump. Not six, only four.

Re: Re: solenoid pack
 

Okay, so as not to be TOO much of a smarta$$ (ha, as if that's gonna happen :D)

Shift Solenoids 1, 2 and 3 are mounted to the control valve. According to the manual, "These solenoids are turned on or off occording to signals sent from the TCU. The gear positions are changed according to the on and off condition of these solenoids." Shift Solenoid 3 is "turned on or off according to the signal sent from the TCU. This operation controls the engagement and disengagement of the overrunning clutch."

Duty Solenoid A is also mounted to the control valve and controls line pressure (Thus the full line pressure from the "resistor mod" which disables duty solenoid A).

Duty Solenoid B is mounted to the control valve also and controls Lock up. It controls the lock up control valve which provides "smooth engagement" of the lock-up clutch.

Duty Solenoid C is mounted on the inside of the extension case. Its signal from the TCU "controls the transfer control valve for controlling the transfer clutch hydraulic oil pressure."

So, there's my "Reader's Digest" version of the manual's explanation of the SIX solenoids (3 Shift, 3 Duty).

Since there are only 4 solenoids, some of those puppys are doing double duty.

Here's a diagram showing the location of the solenoids.

Randy,
The 4 solenoid pack that was shown to me had 2 shift solenoids, 1 lock up & 1 fluid pressure, could it be that the tranny techs don't consider the other 2 solenoids vital?

ALL of the solenoids are vital. I can see where it could look like 4 solenoids. The duty solenoids are separate units. They didn't want to fool with duty solenoid C (inside the extension case). The shift solenoids are in a single assembly. So, perhaps they were showing you solenoid A (line pressure), B (lock-up) and the single assembly with your three shift solenoids. That's the only thing I can think of. Print out the diagram and take it back to them and ask them why they've told you there were only four. I mean, I'm not trying to lead you astray. You can clearly see by the diagram that there are six solenoids, not four, unless, I suppose, yours is FWD. I know there was a wiring difference from the 92's to the later model years, but yours is a '92, right?

Damn, you got that down randy!
:D

Lwin