42RLE Harsh Shifting: High Line Pressure, Bore Wear, and the Real Fix

42RLE Harsh Shifting: High Line Pressure, Bore Wear, and the Real Fix

42RLE Harsh Shifting: High Line Pressure, Bore Wear, and the Real Fix

A 42RLE that slams into gear, bangs the 1-2, or thumps when you drop it into Drive is almost never "just worn clutches." On this unit, harsh shifting is a pressure problem far more often than a friction problem, and the two most common root causes are a worn pressure regulator bore in the valve body and an open circuit on the line pressure solenoid. Both make the transmission run at or near maximum line pressure all the time, and both get misdiagnosed into an unnecessary rebuild.

This guide walks the diagnosis in the order that costs you the least money, using published Chrysler and Sonnax data, and tells you which part actually fixes it.

First: know which 42RLE you have

There are two hydraulically different 42RLE families, and they fail differently.

According to Sonnax's 42RLE valve body identification guide, beginning in 2007 with the Chrysler Sebring 2.4L and 2.7L this transmission got electronic line pressure control. Prior to that, the 604, 606 and 42RLE were fixed line pressure transmissions. Chrysler calls the later one VLP, for Variable Line Pressure.

You can tell them apart from outside the case. Sonnax notes that a VLP unit has an additional electrical connector sticking out of the case next to the range sensor connector. It will be either 6-pin or 5-pin; early connectors had 6 pins with the #1 pin unused, and at some point it changed to a 5-pin configuration. Three wires go to the pressure sensor and two wires go to the pressure solenoid. The TCM uses the pressure sensor as line pressure feedback to adjust pressure to load. Sonnax also points out that the solenoid pack is still used on the VLP valve body, exactly as it was on the non-VLP units, so seeing a solenoid pack tells you nothing about which family you have.

Why it matters: on a VLP unit you have an electrically controlled failure mode available to you, and a specific set of codes. On a pre-2007 fixed-pressure unit you do not, and the diagnosis goes straight to hydraulics.

Diagnosis order that does not waste money

1. Scan first, and read the pressure data, not just the codes

Sonnax technical communication specialist Jim Mobley, writing in Diagnosing Chrysler Transmission Max Line Pressure & P0933, P0869, P1745 Codes, makes a point that saves entire diagnostic days: there is no Chrysler code for a circuit fault on the pressure control solenoid (PCS) line pressure circuit. The vehicle instead throws one of these:

  • P0933 - Line Pressure Sensor Performance. Sets when actual line pressure reads more than 172.4 kPa (25 psi) higher than desired line pressure, but is still less than the highest line pressure ever used in the current gear. Mobley warns that with a max-line condition this code may incorrectly send you to the line pressure sensor.
  • P0869 - High Line Pressure. Sets when actual line pressure is consistently higher than the highest desired line pressure ever used in the current gear. The code description does mention a possible open-circuit fault for the PCS line pressure solenoid.
  • P1745 - Line Pressure Too High for Too Long. Per Sonnax, this code is for the 42RLE and 62TE only, and typically requires the "Clear Variable Line Pressure (VLP) Counters" procedure to be run with a scanner under miscellaneous functions.

P1745 on a 42RLE is your strongest single clue that the harsh shift is a pressure problem, not a clutch problem.

2. Compare actual line pressure against desired

Sonnax gives the numbers to test against. Normal OE pressure is a 60 psi minimum and 150-160 psi maximum at stall (unit dependent). If you are looking at actual line pressure pegged at 150-160 psi at idle in Park, Neutral and Drive, and 250 psi in Reverse, that may indicate an open circuit for the PCS line pressure solenoid.

The scanner signature Mobley documents for an open circuit is worth memorizing: line pressure duty cycle sitting at a fixed value, line pressure at 160 psi, and desired line pressure sitting at the 125 psi default with no activity. Flatline with no activity is the tell. Mobley adds that max line pressure is sometimes mistaken for aftermarket tuning, and the difference is that tuning may run a higher max than 160 psi but it will not be flatlined with no activity like a circuit fault.

One caution from the same article for 42RLE work specifically: line pressure duty cycle is not available on all scanners for the 62TE, 40TES, 41TES and 42RLE. If your tool will not show duty cycle, you fall back to actual-versus-desired pressure and to the circuit test below.

3. Test the solenoid ground control circuit before you buy anything

Mobley's non-invasive test: put a low-current clamp on the PCS ground control wire back to the PCM, clear codes, and monitor the circuit key-on/engine-running in Park or Drive. Current flow varies from 0.20 to 1.00 amps. If you see current flow, it is not an open circuit. He also notes the same circuit shorted to ground will show current flow, but that produces the opposite complaint, a low-pressure condition. He adds that if the other solenoids work and code P0882 (low voltage supply) is not present, the supply side of the circuit is usually not at fault, and that the condition can be intermittent rather than constant.

Note one 42RLE-specific detail from that article: on the 42RLE, 40TES and 41TES the pressure control solenoid is separate from the solenoid pack. That is good news for your wallet. You are not forced to buy a complete pack to address a line-pressure solenoid fault on these units.

4. If it is not electrical, it is the bore

If pressure control is electrically healthy and the unit still bangs, the pressure regulator bore is the next stop, and on this family it is a known wear point.

The causes, ranked

  1. Worn pressure regulator bore in the valve body. Sonnax states plainly that wear at the inner bore causes high line pressure, harsh shifting and erratic converter apply pressure. Wear at the spring end of the bore does the reverse, allowing line pressure to exhaust and producing low line pressure, soft shifts and burnt clutches, and that same wear also affects converter flow and the lube circuit. That is why one worn bore can produce two opposite complaints depending on where it wore.
  2. Open circuit on the PCS line pressure solenoid (2007-up VLP units). Max line pressure all the time, harsh everything, often with P1745, P0869 or P0933 stored.
  3. Failed or contaminated line pressure solenoid itself. Same symptom set, but current flow is present and the fault is at the solenoid rather than the wiring.
  4. Accumulator bore and piston wear. Sonnax lists slide shifts, high CVIs, 1-2 shudder and coastdown clunk as the symptom set addressed by its 42RLE accumulator piston and sleeve kits (92834-03K and 92834-05K), which fit all three accumulator case bores.
  5. Adaptive values that were never relearned. Covered below - this one is free to fix and gets skipped constantly.
  6. Cross-connected speed sensors after a rebuild. If the complaint is a shuttle between first and second the instant you select Drive, see the R&R note below before you condemn anything hydraulic.

The fix: which part, and why

Match the part to what the diagnosis actually found.

If the line pressure solenoid circuit is the fault (2007-up)

Replace the pressure control solenoid. Because Sonnax confirms this solenoid is separate from the solenoid pack on the 42RLE, this is the cheap door into the repair, and it is the correct one when your current-clamp test and pressure data point at the PCS circuit.

42RLE EPC pressure control solenoid for 2007-up VLP transmissions
42RLE EPC Pressure Control Solenoid, 2007-Up - the separate line pressure solenoid used on VLP units.

If the solenoid pack or its internal switch valve is the fault

The solenoid pack is the right call when the shift solenoids themselves are the problem, not the line pressure circuit. A 42RLE shift solenoid block pack covers the 2003-2013 range, and our full transmission solenoid catalog lists the 42RLE options by year. Before you spend that money, read our writeup on 42RLE P1775 and P1776 solenoid switch valve codes - those two codes point at a valve body bore, not at the pack, and replacing the pack for them is one of the most common wasted repairs on this unit.

If the pressure regulator bore is worn

A worn bore is not fixed by any bolt-on part. Sonnax's correction is to recondition the bore and install an oversized pressure regulator valve that restores valve-to-bore clearance so the regulator maintains correct pressure in all ranges. Sonnax lists 92835-29 for VLP units and notes that non-VLP units can be serviced with 92835-24, with tooling F-92835-TL29 called out for the VLP valve. That is machine work; if you are not set up to ream and hone a valve body bore, this is the point where a reconditioned valve body or a shop with the tooling is the cheaper path.

Do the relearn - and know when not to

The 42RLE adapts to itself using clutch volume index values, the volume of fluid needed to stroke each clutch return spring. Sonnax's 42RLE parts catalog lists "High CVIs" and "High L/R clutch volume index (CVI over 100)" among the symptoms its parts address, so CVI is very much a live diagnostic on this unit.

ATRA's Chrysler Quick Learn bulletin - written for the 45RFE, which uses the same Chrysler adaptive strategy - gives the rule most shops get backwards: Quick Learn should not be used as a remedy for shift quality complaints. Quick Learn resets more than 70 learn parameters to preset values and requires all of them to be relearned. It should only be used when the transmission has been replaced or overhauled, or when the TCM has been replaced or flashed. After that, an initial drive evaluation is the next step, not another reset.

ATRA's first diagnostic step in that same bulletin applies directly here: verify the shifter linkage is adjusted properly. A misadjusted shifter will not set a PRNDL fault code, but it will cause poor 2-3 shift quality. Check the shifter before you check anything internal - it is free.

Also worth knowing before you tear into a freshly rebuilt unit: ATSG and Transmission Digest technical editor Wayne Colonna documented a 42RLE case where the input- and output-shaft speed sensor connectors were cross-connected during installation, producing a shuttle shift between first and second the moment the vehicle was put in Drive, followed by failsafe with a first-gear-ratio code. He notes the 42RLE uses a yellow tag identifying the correct connector for the output-shaft speed sensor, and that in a scan tool the cross-connection shows as OSS reading rpm while ISS stays at 0 rpm right at startup.

Replace while you are in there

If the pan is coming off or the valve body is coming out, do these at the same time:

  • Filter and pan gasket. A 42RLE filter kit is the cheapest insurance on the job, and a restricted filter will muddy every pressure reading you just took.
  • Accumulator piston seals. You are already at the case bores; if the complaint included slide shifts or a coastdown clunk, address them now rather than going back in.
  • Fluid. Refill with the correct Chrysler ATF+4 specification fluid. This unit is sensitive to fluid, particularly around converter clutch behavior.
  • Full gasket and seal set. If the valve body is coming out for bore work, a 42RLE overhaul gasket and seal kit covers what you will disturb.
  • Clear the VLP counters. On a 42RLE that stored P1745, run the "Clear Variable Line Pressure Counters" routine after the repair, per Sonnax.

Cost and effort

Difficulty scales sharply with which cause you land on.

  • Pressure control solenoid (VLP units): accessible without pulling the transmission. Roughly 1.5 to 2.5 hours including a pan drop, fluid and filter. DIY-friendly with a lift or good jack stands.
  • Solenoid pack: pan down, valve body accessible. Budget 2 to 4 hours plus fluid. Moderate difficulty.
  • Valve body removal and pressure regulator bore reconditioning: 3 to 5 hours of R&R plus bench time, and it requires the correct Sonnax reaming tool. This is shop work, not driveway work. Many shops will simply fit a reconditioned valve body instead.
  • Full overhaul: only if pressure control checks out healthy and you have confirmed clutch damage. A 42RLE rebuild kit plus 8 to 12 hours is the realistic picture, and it is the outcome the pressure diagnosis above is meant to help you avoid.

FAQ

My 42RLE shifts hard only when cold. Is that still a pressure problem?

Cold-only harshness is more often adaptive learning than a failed part, especially on a unit that recently had a Quick Learn performed or a battery disconnect. ATRA's guidance is that after a Quick Learn the adaptive values have to be relearned through driving, and that a harsh engagement the first time the transmission is put in gear after sitting is a specific learn condition with its own procedure, not automatically a failure. If it stays harsh hot as well, or if P1745, P0869 or P0933 are stored, go back to the pressure diagnosis above.

I replaced the solenoid pack and it still bangs into gear. What did I miss?

Two likely answers. First, on a 42RLE the line pressure solenoid is separate from the solenoid pack, so a pack replacement does nothing for a PCS line pressure fault. Second, if the pressure regulator bore is worn, no solenoid fixes it - Sonnax's correction for that condition is bore reconditioning plus an oversized valve, not a replacement solenoid.

Can I just add a shift kit to smooth it out?

No, and it will usually make things worse. A shift kit is designed to firm shifts up; it does not correct excessive line pressure. Fix the pressure control first, then decide separately whether you want a firmer shift feel.

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