Fault Code P0750 'Shift Solenoid A'

[richxd87]

Got this fault code P0750 last night coming back from dinner. Truck was stuck in 4th gear, turned truck on and off and problem persisted. Truck Stayed in 4th even from a stop and did not down shift. Anybody ever encounter this issue and have it not actually be the shift solenoid? Ideas on cost to replace?

Truck is 2012 Ram 2500 Power Wagon, 66RFE, 130k miles on the odometer.

Located in Houston, TX if anybody has any good transmission shop recommendations.

Thanks!

[coder]

Did a quick google search on "2012 ram P0750" found a couple of videos that should give you an idea of what's involved.

How to Change the Solenoid Pack In a Dodge 68RFE (P0750)
https://youtu.be/Th7-Z9zbpJ4

Is your Dodge Ram stuck in 4th Gear? Here's what will fix it!
https://youtu.be/1in3vPg6XG8

[Ak68w]

I had the same problem. Bad shift solenoid. It is going into limp mode most likely. Mine would usually reset after restart. until 1/4 mile down the road. Parts and labor for the solenoid was 850$

[richxd87]

Finally brought the truck to a shop and after pulling the pan and filter, they sent me this picture of the filter. They claim clutch material like this in the filter means the transmission is on its way out. Is this amount of debris in the filter cause for major concern?

Truck is a 2012 with 128k miles on it.

Side note, they did bench test the solenoid pack and confirmed error with the part.

[Rodeoflyer]

I'd like to see those pictures of the filter. For some reason I can't see them.

I lost the transmission in my 2016 at 92k miles. It went into limp mode (shift solenoid A code), took it to the dealer to have the solenoid recall done and it was full of clutch material like yours. The service manager told me the same thing (on it's last leg) so I waited until it finally lost reverse gear about 2 months later.

I had Austex transmission here in Austin TX complete the rebuild. They upgraded hard parts to sonnax, added a line pressure booster and a billet valve body for longevity with a 100k mile warranty on the build.

[FordyceCreekTrail]

Cant imagine dropping a transmission on a heavy duty truck under 300K miles let alone 100K.

[Rodeoflyer]

With mine, whether it was the replacement solenoids or the PCM update/flash it shifted much better than the factory setup, that is before it failed. I really blame RAMs factory tuning or the solenoid issues for my stock transmissions failure.


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[FordyceCreekTrail]

Either way these kind of reliability problems hold FCA back more then anything.

[Rodeoflyer]

I agree. It's obviously why they went to ZF for the 8 speed. However....I would rather have a built 66/68/65 than a ZF. It's cheaper to rebuild and maintain IMO. A lot of aftermarket support now and can be built bulletproof.

The instructors at the training center say that Chrysler defines "life" as 100k.

[Oilbrnr]

With mine, whether it was the replacement solenoids or the PCM update/flash it shifted much better than the factory setup, that is before it failed. I really blame RAMs factory tuning or the solenoid issues for my stock transmissions failure.

So do you think the damage happened before or after the work that was done? Also curious, was that the solenoid pack recall that was put out in late '16 early '17 and did you put off having it done?

I'm very interested in the mods that were done on your rebuild. Maybe because it gives me flashbacks to my battles with the 47RFE in my then new '99 CTD.

[Rodeoflyer]

I definitely ignored the recall. I won't ignore another recall for drivetrain.

I think the major damage was caused by the faulty solenoid and factory trans programming. I should have taken it in as soon as the recall was issued. However...Chrysler defines 'lifespan' as 100k miles.

The billet VB is the major upgrade.

Since its early production in 1999, the RFE platform has been plagued with many issues. Some of the biggest problems have been premature clutch failure and valvebody wear. The premature clutch failure can be isolated to hydraulic cross leaks and warped valve bodies. Approximately 80-90% of those cross leaks have been found in the OE channel plate casting.

If you look closely at the stock casting with a straight edge, you will notice that there is some severe flexing and warpage. Looking at how the valvebody is fastened to the transmission and being that there are limited contact surfaces it’s no wonder we see so many problems.

For example, fourth gear clutch failure, premature valvebody bores worn, and defective valve lands. So, we decided that the best way to fix this issue was to eliminate channel plate flexing.

Hence, a channel plate made from billet was engineered, also with shallower channels to expedite gear shifts.

For an understanding of the durability we tested the strength of the plate. We put the stock plate on a press that has a pressure gauge. With the edges supported just like factory, we then put a 1.000-inch round bar in the center. At 300lbs of pressure the stock plate warped to .168 and then cracked. We then did the same to our plate. At 1 ton it did not move. We then went to 2 tons with barely any movement. Flex was .021. Then we went to 5 tons and it was .047. So, we decided that we would give it 10 tons…. It flexed to .160 and out of fear we stopped. It didn’t return to zero, but it did however recover to .056.

Further, this valve body comes with Sonnax brand Billet accumulator pistons, laser cut bonded separator plate, and best of all, the accumulator block is precision cut to perfect flatness. In addition, heavier springs are used in place of certain weaker springs in the OE Valve Body to facilitate greater control over the unit’s shifts. We are currently beta testing a 1,200HP 68RFE, and this is the valve body that makes it happen.

This Unit Features:

- Billet Channel Plate

- Billet Anodized SSV Assembly (including end plug)

- Billet Accumulator Pistons

- Billet Accumulator Plate

- Bonded Laser Cut Separator Plate

- Steam Tanking and Pressure Cleaning

- Anodization of SSV bore

- Lathing/Stoning of contact surfaces to 0.001”

- Heavier Seat Pressure Springs

- Overdrive Spring Shim

- Billet Triple Land Anodized L/R Switch Valve

- Shallower Oil Passages to facilitate faster shifting

- Anti-flexion billet material to prevent crossleakage

- Ability to run up to 300PSI of Line Pressure (225 recommended to avoid excess heat)

[Rodeoflyer]

RAM should own up and correct their trans and lifter issues. https://www.ramforum.com/threads/cracke ... fe.139345/

My factory thermostat also failed around the same time.

[Oilbrnr]

Good info!

Are all those improvements as part of the VB assembly, or does it require complete teardown of the transmission?

(Sorry, full teardown is not something I've attempted due to the necessary training and tools. Anything else, bring it!)

-don-

[Rodeoflyer]

The VB doesn't require a teardown. I'd recommend upgrading that asap.

[Oilbrnr]

Is Austex the source for this then?

[Rodeoflyer]

I'm running the DNJ https://transmissioncenter.net/shop/dnj ... 1999-2011/

There's another one more expensive https://nextgendiesel.com/products/68rf ... gLmUfD_BwE

[Rodeoflyer]

If you enlarge the pic it's a DNJ. Maybe they modified it?

https://nextgendiesel.com/products/68rf ... gLmUfD_BwE

[Thammond]

How is your transmission from aus-Tex holding up?

[waldo]

The 66RFE in my 16 was a complete piece of garbage. The solenoid pack was replaced once under the recall and again a year later. It still overheated climbing the mountain to my cabin when in 4WD,

Traded it for a 19 with the ZF and life is good again.

[ACL123]

Had the same code and replaced the solenoid pack but its still in limp mode. Do I need to get the time flashed or something?

2005

[Pit Slave]

You will most likely need to do a relearn on it.

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[Pit Slave]

Had the same code and replaced the solenoid pack but its still in limp mode. Do I need to get the time flashed or something?

2005

You will most likely need to do a relearn on it.

Sent from my rotary phone using Tapatalk

[ACL123]

Had the same code and replaced the solenoid pack but its still in limp mode. Do I need to get the time flashed or something?

2005

Should read "Tcm flashed"

[ACL123]

Had the same code and replaced the solenoid pack but its still in limp mode. Do I need to get the time flashed or something?

2005

You will most likely need to do a relearn on it.

Sent from my rotary phone using Tapatalk

Ok thanks

[ACL123]

Had the same code and replaced the solenoid pack but its still in limp mode. Do I need to get the time flashed or something?

2005

Turns out mine was a bad pcm