Featured in this issue:Sonnax Voted Tops for Parts & Tools!Outsmarting 4L80-E Overdrive Roller Clutch FailureTwo Simple Parts Help Guard Against 4L60/E Clutch & Shift ConcernsProtect Against 4T60/65-E ComebacksNew Performance Parts & Catalogs

If the stator is misaligned or if the incorrect stator is used, it may cause no movement, converter charge concerns, input shaft failure and even converter damage in GM 4L60-E, 4L65-E and 4L70-E transmissions. Verifying the correct stator for your application can be broken down into three easy checks that look at the shaft, pump cover and stator itself.

1. Identify Shaft Type

It is extremely important to take note of sealing ring location because there are a few variations of shafts out there (Figure 1). You may find a pump cover that does not have the ISS hole drilled, but has a reluctor-style stator with no reluctor on the input shaft (see “Anomaly” in Figure 1). This situation will require the use of an ISS stator.

Figure 1 – 300mm Shaft Sealing Ring Locations

2. Identify Early vs. Late Pump Style

Using a ruler or straightedge, draw a line through the center of the pump bolt holes. Make note of whether the converter feed hole is positioned slightly off to the right or left of the line (Figure 2).

Figure 2 – Pump Cover: Converter Feed Hole in Relation to Bolt Holes

3. Identify Early vs. Late Stator Style

To determine which stator will work in the pump, look at the converter feed and lube holes in the stator. Make note of whether they are directly in line with one another or if the converter feed hole is positioned to the right of the lube hole (Figure 3).

Figure 3 – Stator: Converter Feed Hole in Relation to Lube Hole

As you can see with these three quick checks, you can easily determine which stator best fits your application. In earlier pumps, the converter feed hole will be just to the right of the line while — in the stator — the converter feed and lube holes will be directly in line. In later-model or GM’s most recent pumps, the converter feed hole will be just to the left of your line while — in the stator — the converter feed hole will be to the right of the lube hole.

Caleb Perham is a Sonnax product support representative. He is a member of the Sonnax TASC Force (Technical Automotive Specialties Committee), a group of recognized industry technical specialists, transmission rebuilders and Sonnax Transmission Company technicians.

'93-'94
Number of Valve Body Solenoids	4
EPC Solenoid	Early
3-2 Control Solenoid	PWM (metal, white) 10-15 Ω
TCC Solenoid	None
Manual Valve	Non-vented
Casting	Bottom: Open port over 3-2 valve Bottom: No vent at manual valve
Part Number	GM046 (Warranty Only)

'95
Number of Valve Body Solenoids	5
EPC Solenoid	Early
3-2 Control Solenoid	PWM (metal, white) 10-15 Ω
TCC Solenoid	PWM (metal, white) 10-15 Ω
Manual Valve	Non-vented
Casting	Bottom: Open port over 3-2 valvet Bottom: No vent at manual valve
Part Number	[GM047]

'96-'00
Number of Valve Body Solenoids	5
EPC Solenoid	Early
3-2 Control Solenoid	ON/OFF (plastic, white) 20-31 Ω
TCC Solenoid	PWM (plastic, gray) 10-15 Ω
Manual Valve	Vented
Casting	Bottom: 3-2 Port cast shut Bottom: Vent at manual valve
Part Number	[GM048]

'00-'02 Annular Lockup
​​​​​​​​​​​​​​
Number of Valve Body Solenoids	5
EPC Solenoid	Early
3-2 Control Solenoid	ON/OFF (plastic, white) 20-31 Ω
TCC Solenoid	PWM (plastic, gray) 10-15 Ω
Manual Valve	Vented
Casting	Bottom: TCC annular exhaust port Top: TCC annular exhaust port Bottom: 3-2 Port cast shut Bottom: Vent at manual valve
Part Number	[GM049]

'03-'08
Number of Valve Body Solenoids	5
EPC Solenoid	Late
3-2 Control Solenoid	ON/OFF (plastic, white) 20-31 Ω
TCC Solenoid	PWM (plastic, gray) 10-15 Ω
Manual Valve	Vented
Casting	Bottom: TCC annular exhaust port Top: TCC annular exhaust port Bottom: 3-2 Port cast shut Bottom: Vent at manual valve
Part Number	[GM051]

Colorado, Hummer H3
​​​​​​​​​​​​​​
Number of Valve Body Solenoids	5
EPC Solenoid	Late
3-2 Control Solenoid	ON/OFF (plastic, white) 20-31 Ω
TCC Solenoid	PWM (plastic, gray) 10-15 Ω
Manual Valve	Vented
Casting	Bottom: Angled by EPC and accumulator valve Bottom: TCC annular exhaust port Top: TCC annular exhaust port Bottom: 3-2 Port cast shut Bottom: Vent at manual valve
Part Number	GM052 (Warranty Only)

The GM 4L60-E series started production in 1993 and was used in a variety of different applications for over 20 years. It’s still a very popular unit for many shops, and common problems have largely been identified by most builders at this point.

Since PWM controls were implemented in 1995, builders have been fighting issues with TCC slip codes. The ’98-later models added EC3 controls, which further complicated the issue because the converter will rarely see full lockup. Under most conditions, 20–40 RPM of TCC slip is normal operation.

The addition of EC3 controls had a significant side effect: the constant oscillation of the TCC regulator/isolator valves in the aluminum valve body can cause casting wear, which will allow critical apply pressure to exhaust. The common fix is to ream the bore and use Sonnax TCC regulator and isolator valve kit 77754-04K to resolve the issue. It’s a great solution and helps with the TCC regulator portion of the bore by providing a wear-resistant sleeve and valve to prevent future wear.

While we include a lengthened isolator valve in the kit to operate in unworn portions of the bore, it’s important to note that casting wear can occur on this end just as it does with the regulator valve. Many builders assume that installing 77754-04K will restore the integrity of the entire bore, but the reality is that many of these units see such significant mileage that casting wear (detectable via vacuum testing) can be a real concern in the isolator section.

Figure 1 – OE ’98-Later PWM Valve Lineup

Fortunately, Sonnax offers a solution for this as well: oversize the bore using reamer 77754-RM5 or reamer tool kit F-77754-TL4 and then install isolator sleeve kit 77754-ISO. This allows the new isolator valve from 77754-04K to be installed in a wear-resistant sleeve, completely eliminating leakage in the bore and the potential for costly comebacks from casting wear.

Figure 2 – Sonnax Regulator & Isolator Valve Bore Repairs

Tory Royce is a Sonnax technical support engineer and product support specialist and a member of the Sonnax TASC Force (Technical Automotive Specialties Committee), a group of recognized industry technical specialists, transmission rebuilders and Sonnax technicians.