Hello and welcome. Here are a few thought that came to mind.

1) The wrong trans. fluid was used. (Use only Chrysler approved ATF+4 trans. fluid)

2) The valve body passages might be clogged for reverse gear.

3) Might be either the input/output speed sensor.

How's the condition of the tranny fluid?

Try doing a complete fluid change and see if that works. (Removing around 9 qts. of fluid)

 

Thank you for your input. Transmission was flushed at 245,000 and now has 289,000. (Since doing this, I have read all the pro/cons about doing just that.)
1. When I dropped the pan and replaced the filter, I let as much fluid as possible drain out and measured it before adding more ATF+4 (6 quarts).
2. You mention the valve body reverse passage being possibly clogged, even on a brand new one or are you referring to the passages within the transmission housing itself?
3. If the housing would be the case, Any thoughts on how to determine which passages are for reverse and the proper way to clean them out while still in the car?
4. Yeah, I started cross threading the input sensor, decided to not screw it up and wait for another day where I could get a better view of it before trying again.
5. The color of the fluid coming out during the filter change looked clean and solid red.

Thanks again for your time and consideration, Bobby

 

Page 2

Thank you for your input. Transmission was flushed at 245,000 and now has 289,000. (Since doing this, I have read all the pro/cons about doing just that.)
1. When I dropped the pan and replaced the filter, I let as much fluid as possible drain out and measured it before adding more ATF+4 (6 quarts).
2. You mention the valve body reverse passage being possibly clogged, even on a brand new one or are you referring to the passages within the transmission housing itself?
3. If the housing would be the case, Any thoughts on how to determine which passages are for reverse and the proper way to clean them out while still in the car?
4. Yeah, I started cross threading the input sensor, decided to not screw it up and wait for another day where I could get a better view of it before trying again.
5. The color of the fluid coming out during the filter change looked clean and solid red.

Thanks again for your time and consideration, Bobby

 

1. When I dropped the pan and replaced the filter, I let as much fluid as possible drain out and measured it before adding more ATF+4 (6 quarts).

Six quarts on a spill-and-fill is way over what Chrysler says you should get; their spec is ~4 quarts for that. Definitely check the fluid level - you may be over-filled.

 

Thank you for your input. Transmission was flushed at 245,000 and now has 289,000. (Since doing this, I have read all the pro/cons about doing just that.)
1.When I dropped the pan and replaced the filter, I let as much fluid as possible drain out and measured it before adding more ATF+4 (6 quarts).
2. You mention the valve body reverse passage being possibly clogged, even on a brand new one or are you referring to the passages within the transmission housing itself?

This was your first big mistake! People don't listen, if it was working fine, why drop the pan?

Dirt, dust and flying insects can get inside the transmission during the time pan is off, it just take a split second.

 

Dirt, dust and flying insects can get inside the transmission during the time pan is off, it just take a split second.

Q: So, what is the direction of fluid flow through the transmission??

A: Drains and collects in the pan, is pulled through the (submerged) filter by the pump and distributed through the pressure side of the unit.

Unless you have the valve body out, anything that would get into the transmission would have to get past the filter as the fluid cycles.

While I tend to agree with the "If it ain't broke, don't borrow trouble" reasoning, dropping the pan is not the open invitation to disaster that you want to believe it is. The same dust, debris and bugs could (technically) get into your engine when you do an oil change. Or do you not recommend those either?

 

What am I missing?

Bobby,
Have you actually checked the ATF level per Chrysler procedure? (both cold and hot - you don't mention it in your posts)
When you pull the dipstick, are there any air bubbles on it?

By 'valve solenoid' you mean the shift solenoid pack? that sits on the front of the trans case.
Valve body is a hydraulic assembly that sits inside the trans above the oil pan, if there are blockages or leaks in the valve body or low/reverse accumulator that might cause slow or non shift to reverse.

And to clarify: it won't shift into reverse (stays in neutral) until you give it gas or it will shift into reverse but will not move the van?

 

Just shouting from the side

I always drop a pan and never had issues after that.
i believe people come here asking question after problem occurs and after they chance fluid by dropping pan.
i'm trying to say that they first have problem, then they try to solved it by chancing fluid and drop the pan. Then they come here and ask about problem
Never heard dropping pan can cause problems. But there are so many ways to do that (ignoring cleanliness etc...)

 

Levy, I failed to mention that shortly after the reverse issue started, I began to hear a loud whining noise from the tranny as well. After doing research online, the cheapest possible fix was to drop the pan and replace as much fluid as possible along with the filter in which I did. I did check the fluid level prior to all of this ( and afterwards) per the manual and determined either cold or hot, the fluid level was correct on the dipstick. Before I forget, swapping out the filter and fluid resolved the whining issue. I mistakenly said I replaced the valve body and instead it was the solenoid pack. When I place the gear selector into reverse, you feel the van move for a moment and then do nothing unless you hit the gas. At that time, it feels like frozen brakes, but only during reverse. I will work on the various other recommendations made and keep y'all up to date. Thank you to everyone who offered advise, Bobby

 

Honestly you probably have a clutchpack improperly applying or a one-way clutch that's stuck on or something. I've seen (and replaced) fused-together clutchpacks before on other manufacturer's transmissions, but because it works fine for a moment, it makes me wonder if it's something being improperly applied. The Factory Service Manual diagrams would show this if you can trace through what happens in various gear positions. If swapping the solenoid pack didn't work, the only other options that might help are swapping a valvebody (possible stuck valve or a crack in it allowing a cross-leak) or a Transmission Control Module (TCM) and see if that fixes it. Beyond that, I'd replace the transmission. But I'd talk with a shop familiar with A604's / 41TEs before going any further.

Do all forward gears work properly?

 

Honestly you probably have a clutchpack improperly applying or a one-way clutch that's stuck on or something. I've seen (and replaced) fused-together clutchpacks before on other manufacturer's transmissions, but because it works fine for a moment, it makes me wonder if it's something being improperly applied. The Factory Service Manual diagrams would show this if you can trace through what happens in various gear positions.

Here's the Input and Holding clutch engagements for the 41TE:

 

Just to eliminate any electrical/electronic fault, I'd unplug the solenoid pack or pull the TCM relay. This will put the trans in "Limp" mode giving you 2nd gear and reverse. It likely won't change anything but will verify that it's an internal trans fault.

If it wasn't such a pain, I'd pull the diff cover and look at condition of the gears, bearings and pins - it could have loose or worn parts and 'clashes' when direction is reversed. If the pan was relatively clean (when you pulled it) without excessive metal dust, the diff is probably fine.

If all else failed, I'd dump a bottle of trans medic or other seal conditioner before changing the whole trans (not much to loose at that point)

 

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.

 

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.

 

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

 

 

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.

 

Cheers for resolution and closure,
Thanks!

 

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?