[Joel_B]

Thanks Doug. Looking at that chart for a few minutes, I wonder if the underdrive clutch is applying all the time. Does 4th gear work fine or does it drag in 4th too?

 

[douggro]

Thanks Doug. Looking at that chart for a few minutes, I wonder if the underdrive clutch is applying all the time. Does 4th gear work fine or does it drag in 4th too?

"The Solenoid/Pressure Switch Assembly (Fig. 317)
is external to the transaxle and mounted to the
transaxle case. The assembly consists of four solenoids
that control hydraulic pressure to the LR/CC,
2/4, OD, and UD friction elements. The reverse
clutch is controlled by line pressure from the manual
valve in the valve body. The solenoids are contained
within the Solenoid/Pressure Switch Assembly, and
can only be serviced by replacing the assembly.
The solenoid assembly also contains pressure
switches that monitor and send hydraulic circuit
information to the TCM. Likewise, the pressure
switches can only be service by replacing the assembly.
The solenoids receive electrical power from the
Transmission Control Relay through a single wire.
The TCM energizes or operates the solenoids individually
by grounding the return wire of the solenoid
needed. When a solenoid is energized, the solenoid
valve shifts, and a fluid passage is opened or closed
(vented or applied), depending on its default operat-
ing state. The result is an apply or release of a frictional
element.
The 2/4 and UD solenoids are normally applied,
which by design allow fluid to pass through in their
relaxed or “off” state. This allows transaxle limp-in
(P,R,N,2) in the event of an electrical failure.
PRESSURE SWITCHES
The TCM relies on three pressure switches to monitor
fluid pressure in the L/R, 2/4, and OD hydraulic
circuits. The primary purpose of these switches is to
help the TCM detect when clutch circuit hydraulic
failures occur. The range for the pressure switch closing
and opening points is 11-23 psi. Typically the
switch opening point will be approximately one psi
lower than the closing point. For example, a switch
may close at 18 psi and open at 17 psi. The switches
are continuously monitored by the TCM for the correct
states (open or closed) in each gear as shown in
the following chart:
PRESSURE SWITCH STATES
GEAR L/R 2/4 OD
---------------------------
R OP OP OP
P/N CL OP OP
1st CL OP OP
2nd OP CL OP
D OP OP CL
OD OP CL CL
(OP = OPEN; CL = CLOSED)"

And Underdrive clutch application would trip a pressure switch in the solenoid pack and set a code, most likely. And the OP put in a new solenoid pack..So if the Underdrive clutch is being applied, it's a mechanical fault not a control fault and not being detected by the TCM.

 

[Joel_B]

Good post Doug, thank you for researching that; I'm totally slammed with some non-car matters at the moment.

Given what Doug posted, I'm leaning one of two ways:
1. If the underdrive clutches are physically fused together and therefore always engaged, then Park and Neutral should feel like being in first gear, given the chart Doug posted. Bobby, if you start the van in Neutral, what happens? Does it try to drive forward?
2. If not... and assuming there are no transmission codes (Bobby, check the 700-series codes in your scanner and make sure that you have one that can specifically read transmission codes), then I'd suspect the computer that controls them. While they aren't cheap to replace, they're much cheaper and faster than replacing the transmission, and I've definitely heard of TCMs failing on the 2001-2003s. The 2004+ vans had one computer for both engine and transmission.

 

[Bobby Boudain]

Joel,

In response to your question regarding does all forward gears work, the answer is yes and actually, reverse started working again yesterday. I don't expect it to last very long and will look into your recommendations as well. Thank you for your response. Bobby

 

[Bobby Boudain]

Joel,

In response to your question regarding does all forward gears work, the answer is yes and actually, reverse started working again yesterday. I don't expect it to last very long and will look into your recommendations as well. Thank you for your response. Bobby

 

[Bobby Boudain]

To everyone whom was kind enough to put their 2 cents worth of thought into my dilemma: I have never claimed to be a "mechanic", only a parts changer and it clearly shows here. The real issue was a shot set of ceramic brake pads on the front rotors! When I would attempt to back up, the steel backing plates would get into a jam and give the impression of transmission issues. I was well aware the pads were in need of changing, just kept putting it off. Thanks again to everyone's recommendations.

 

[FabricGATOR]

Cheers for resolution and closure,
Thanks!

 

[marvinstockman]

OP, as with another posting, your van is well past its 'sell by date', and I would certainly start looking for another newer van. That being said, in the 1970's, I had a Toyota Corona that had lost reverse completely. The car had too much rust to put money into, but I would just avoid parking the van where I had to use reverse. Just saying......

 

[Jeepman]

OP, as with another posting, your van is well past its 'sell by date', and I would certainly start looking for another newer van. That being said, in the 1970's, I had a Toyota Corona that had lost reverse completely. The car had too much rust to put money into, but I would just avoid parking the van where I had to use reverse. Just saying......

Just going ahead, weren't planning on going back?