Fixing 4L60-E 1-2 shift issues

Fixing 4L60-E 1-2 shift issues

The complaint

A 1993 Chevrolet 1500 with the 5.0-liter engine and 4L60E transmission has a complaint of second gear starts. The truck seemed to start off in first gear on an initial cold start but would stay in second gear at a stop or even when shifted out of Drive to Park or Reverse and then back into Drive again. The scanner showed the computer commanded a first gear start and both shift solenoids were confirmed to be on with a voltage check. First the shift solenoids were replaced to no avail. Then the valve body was replaced with another complete assembly and shift solenoid feed orifices in the spacer plate were enlarged to .035 in., the same problem remained.

Cause 1

The 4L60E valve body is in second gear by default when the engine is off. Once the engine is started and line and AFL pressure have generated 48 lbs. or more, the 1-2 shift valve will be stroked into first gear. It requires 48 lbs. to overcome the tension of the 1-2 shift valve spring. A deficiency in the line or AFL pressure that allows line pressure to drop below 48 lbs. is going to create second gear starts. The line pressure was checked and it was reading at the correct value of 62 lbs. in the drive range, this ruled out any line pressure, AFL valve or forward accumulator piston problems.

Cause 2

The technician discovered on a subsequent road test that in the manual low range the transmission would bind up. In checking the 1-2 accumulator piston seal and the piston pin bore, the technician observed the 1-2 accumulator piston was missing the rubber seal; refer to Figure 1.

Tech-Talk-Figure-1-600
Figure 1.

When the piston seal is leaking or missing accumulator pressure is going to feed past the second accumulator piston into the band apply circuit and apply the band; refer to the green circled arrows in Figure 2. 

Tech-Talk-Figure-3-1400
Figure 2.

The correction

With a seal installed on the 1-2 accumulator piston (Figure 3), a short road test confirmed the fact that the complaint had been eliminated.

Tech-Talk-Figure-2-600
Figure 3.

You May Also Like

Infiniti G37 RE7R01A chassis codes set

The complaint A 2013 Infiniti G37 equipped with the RE7R01A transmission and the EXT13C transfer case has a complaint of trouble codes C1204 “4WD Solenoid Malfunction” and C1105 “Right Rear Wheel Speed Sensor Fault” stored. Due to extensive damage, the transfer case was replaced, which did not eliminate the stored codes. The shop then replaced

Tech-Talk-Aug-Figure-5-1400

The complaint

A 2013 Infiniti G37 equipped with the RE7R01A transmission and the EXT13C transfer case has a complaint of trouble codes C1204 “4WD Solenoid Malfunction” and C1105 “Right Rear Wheel Speed Sensor Fault” stored. Due to extensive damage, the transfer case was replaced, which did not eliminate the stored codes. The shop then replaced the TCM, but the codes remained. Wiring was checked and was found to be in good condition.

Honda Accord BB7A six-speed: P2720 code set after collision

The complaint A 2015 Honda Accord with a 3.5-liter engine and the BB7A six-speed transmission (seen in figure 1, above), was involved in a minor collision to the left front of the vehicle. The vehicle was drivable and was taken to the transmission shop. Vehicle diagnostics revealed a P2720 “Pressure Control Solenoid D Voltage Low”

Tech-Talk-Aug-Figure-1-1400
42RLE buzzing noise on initial engagement

The complaint A 2005 Jeep Wrangler equipped with the 42RLE transmission had a buzzing noise when the shift selector was moved to the drive position. The vehicle was actually brought in with a shift complaint, at which time the owner of the vehicle also said that the buzzing noise was present since he purchased the

62TE delayed forward engagement

The complaint A 2016 Dodge Journey with the 62TE transmission had a complaint of delayed forward engagement and fluid leaking out of the vent when the transmission is placed in drive only. A code P0740 “Torque Converter Clutch Malfunction” was set. Related Articles – A guide to common GM, Ford and Nissan programming issues –

Ford 6F35 harsh forward re-engagement after stop/start

The complaint A 2014 to 2016 Ford Escape equipped with the 6F35 transmission built on or before Feb. 26, 2016, may have a complaint of a harsh forward or reverse engagement after an active stop/start event. The Malfunction Indicator Lamp may be illuminated and diagnostic trouble code P0C27 “Auxiliary Transmission Fluid Pump Motor Current Low”

Tech-Talk-May-Figure-9

Other Posts

Valve body and component suppliers: A comprehensive list

Looking for a comprehensive list of the industry’s valve body and valve body component suppliers for 2024? TD has you covered. Below, find a list of suppliers including contact information, addresses, etc. Related Articles – Shift Pointers: What to do when the 62TE TRS tab breaks – Going the extra mile: Proving your transmission repair suspicions

ATI introduces pressure regulator valve for Powerglide valve B

ATI Performance Products has introduced a new OEM-style pressure regulator valve for Powerglide valve bodies. According to the company, this OEM-style replacement and will work with OEM mating parts with no modifications. The part no. is 203181 and the valve was made in America. Related Articles – Alto introduces filters for GM 6L series –

ATI-203181
How the Ford engine stop/start system affects transmissions

2018 and later Ford Escape vehicles equipped with a 1.5 L Eco-Boost, 2.0-liter turbocharged engine or the 2L VCTi engines, and the 6F35 transmission, have an engine stop/start system. The stop/start feature can be disabled by the driver and will remain disabled after each key cycle until reactivated by the driver. Some Ford Fusion and

Tech-Talk-May-Figure-1
GM 6L series no-movement conditions: Analysis and repair tips

I am certain that many have experienced a no-movement forward, no-reverse or abnormal pressure condition with a GM 6L series transmission, especially since they are one of the most popular unit families in shops today. So, let’s examine some conditions and causes along with a few diagnostic tips for troubleshooting. We’ll go through a few

TASC-Tip-feature-1400