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The NAG1 (Chrysler's name for the Mercedes 722.6 five-speed automatic) sits behind the engine in the Jeep Grand Cherokee WK and Commander XK, the Dodge Charger, Magnum, and Challenger, the Chrysler 300, and the Sprinter van. It is a strong, well-liked gearbox. But when someone says they need a "shift solenoid" for one, they are almost always describing a different repair than they think.
Here is the part that trips people up: the 722.6 does not have individually serviceable shift solenoids. Every solenoid, both speed sensors, and the internal wiring are molded into a single flat plate called the conductor plate (also called the electro-hydraulic control module), which bolts to the valve body inside the pan. You cannot walk into a parts store and buy solenoid "A." When a solenoid fails, the fix is a conductor plate. That single fact drives the whole cost conversation.
Symptoms of a Failing Conductor Plate or Solenoid
- Limp home mode. The classic NAG1 failure. The transmission drops to a single fixed gear (often feels like a tall 2nd or a locked 3rd) and will not shift. Restarting the engine may clear it briefly, then it returns.
- Harsh, banging shifts or a hard 2-3 shift once the trans is warm.
- Delayed engagement going into Drive or Reverse, especially cold.
- No upshift past 2nd, or the tach flaring between gears as a solenoid bleeds pressure.
- Speedometer works but the trans acts brain-dead when one of the two internal speed sensors (in the conductor plate) drops out.
- Intermittent faults that come and go with temperature as ATF wicks into the connector and bridges pins.
If your unit shows these signs, walk the full list of NAG1 / 722.6 problems before you spend a dollar. The overlap between a bad conductor plate and a simple connector leak is huge, and one costs a fraction of the other.
Common Trouble Codes
| Code | Meaning on the 722.6 / NAG1 |
|---|---|
| P0715 | Input/turbine speed sensor (N2/N3 in the conductor plate) no signal |
| P0700 | TCM has flagged a fault and commanded limp mode |
| P0731 – P0735 | Incorrect gear ratio, 1st through 5th (slip or solenoid not commanding) |
| P0743 / P0748 / P0753 | Solenoid electrical faults inside the conductor plate |
| P0876 / P0868 | Line pressure faults, often connector or plate related |
Pull the codes with a scan tool that reads the transmission module, not just generic engine codes. A basic reader will show P0700 and nothing useful behind it. See our pick for the best scan tool for transmission diagnosis if you are working on this at home.
Check the Connector First — The $30 Fix Everyone Misses
Before you condemn the conductor plate, inspect the 13-pin connector adapter where the external harness plugs into the transmission. The sleeve inside that connector uses an O-ring that hardens with age. When it fails, ATF wicks up the wire strands (capillary action) and travels into the connector, sometimes all the way to the TCM. Fluid between the pins throws random electrical codes and mimics a dead solenoid.
Symptoms of a leaking connector: a wet, oily transmission plug; ATF in the harness boot; and faults that change with temperature. The repair is a new connector adapter sleeve, roughly $20 to $45, plus cleaning the harness. If you catch it early you may never need the plate at all. This is the single highest-value check on the whole job.
Search 722.6 / NAG1 13-pin connector adapters
What the Conductor Plate Job Costs in 2026
If the plate itself is bad, here is the real breakdown. The plate lives under the pan, so every job also becomes a fluid and filter service whether you planned it or not.
| Line Item | Part Price (2026) | Notes |
|---|---|---|
| Conductor plate (aftermarket) | $150 – $250 | URO, Febi, Vaico, Meyle |
| Conductor plate (OE / Mopar) | $280 – $400 | Longer service life |
| 13-pin connector adapter | $20 – $45 | Replace every time you are in there |
| Pan gasket / filter kit | $35 – $70 | Includes the internal filter |
| NAG1-spec fluid (~5 qt) | $60 – $110 | MB 236.14 spec, not ATF+4 |
Parts-only DIY total: roughly $290 to $580. At an independent shop, add 1.5 to 3 hours of labor for the drop, the plate swap, and the fill/relearn. Typical out-the-door shop cost lands between $450 and $850. A dealer will quote more, often $900 to $1,300, because they price the OE plate plus book time and a full flush.
One hard rule: the 722.6 does not take ATF+4. That fluid is for the 45RFE / 545RFE / 68RFE family. The NAG1 wants Mercedes 236.14 spec fluid (Mopar NAG1 ATF, Shell 3403-M-115, or an equivalent full-synthetic). Get the fill wrong and you will chase phantom shift complaints for weeks. See the NAG1 fluid change cost and spec guide for the exact fill.
Compare NAG1 / 722.6 conductor plates
Doing the Job Yourself
- Get it up level. The 722.6 has no dipstick on most Chrysler applications. You fill and check by transmission temperature at a level fill plug, so the vehicle must sit flat.
- Drop the pan, drain, and pull the filter. Expect a mess. Have a wide drain pan and rags.
- Unbolt the old plate. Note the Torx sizes and keep the bolts organized. The plate lifts off the valve body once the connector pin sleeve is released.
- Transfer nothing. The new plate comes complete with solenoids and speed sensors. Seat the new connector sleeve with a fresh O-ring, lightly oiled.
- Fill to temperature. Add fluid, run the selector through the gears, and set the final level with the trans at spec temperature (usually around 45 C / 113 F). Overfilling foams the fluid and causes its own shift faults.
- Clear codes and drive. The TCM relearns shift adaptation over the next several drive cycles, so the first few miles may feel firm before it smooths out.
If you would rather confirm the diagnosis before you open the pan, our guide on how to test a transmission solenoid and the best multimeter for solenoid testing will let you check resistance at the connector pins first. A conductor plate that reads open or shorted on a solenoid circuit is a confirmed replacement.
Conductor Plates, Adapters & Filters — Ships Same-Day
Our companion shop gearboxinsider.com stocks 722.6 / NAG1 conductor plates, 13-pin connector adapters, filter kits, and the correct 236.14-spec fluid so you can do the whole job in one pass. Same-day ship before 2pm Eastern.
Shop Gearbox Insider →When It Is Not the Plate
A conductor plate cures electrical and solenoid faults. It will not fix worn clutches, a slipping pump, or a torn valve body. If the fluid is burnt and black, or the unit slips in every gear after a fresh plate, the damage is deeper. At that point you are comparing a valve body rebuild against a full overhaul. Read NAG1 problems and rebuild cost and the 722.6 conductor plate replacement walkthrough to draw the line between a $400 repair and a $3,000 one. If your unit is a Mercedes-badged W5A580, the W5A580 limp mode fix covers the same hardware.
FAQ
Can I just replace one solenoid on a 722.6?
No. The solenoids are integrated into the conductor plate and are not sold or serviced individually. A single failed solenoid means a new plate.
Will a new conductor plate fix my limp mode?
If the limp mode is caused by a bad speed sensor or solenoid in the plate, or a leaking connector, yes. If it is caused by worn clutches or low line pressure, no. Confirm with codes and a road test first.
Does the NAG1 take ATF+4?
No. Use Mercedes 236.14 spec fluid (Mopar NAG1 ATF or equivalent). ATF+4 belongs in the RFE-family Chrysler transmissions, not this one.
How long does the job take?
A confident DIYer with the vehicle on ramps can do a plate and fluid service in an afternoon. A shop books it at roughly 1.5 to 3 hours.