Green Thunder

iTrader: (11)

Harsh 1-2 Upshift, SES, MIL, or CEL Illuminated, DTC P1870 Set (Replace Valve Body) #01-07-30-023B - (Mar 22, 2002)
Harsh 1-2 Upshift, SES, MIL, or CEL Illuminated, DTC P1870 Set (Replace Valve Body)
1996 Buick Roadmaster

1996 Cadillac Fleetwood

1999-2000 Cadillac Escalade

1996-2000 Chevrolet Camaro, Corvette

1996-2000 Pontiac Firebird

1996-2000 Chevrolet and GMC Light Duty Truck Models

1996-2000 Oldsmobile Bravada

with 4L60-E Automatic Transmission (RPO M30)

Built Prior to January 15, 2000 (Julian Date 0015)

This bulletin is being revised to update VIN Breakpoint Date information and revise the Parts Information table. Please discard Corporate Bulletin Number 01-07-30-023A (Section 07 -- Transmission/Transaxle).

Condition
Some customers may comment on a harsh 1-2 upshift and the Check Engine Light or Service Engine Soon indicator is illuminated.

Diagnosis


Typically, these vehicles will have been driven more than 32,000 km (20,000 mi) before this condition occurs.

The scan tool may show a DTC P1870 set as a history code.

A harsh 1-2 shift or DTC P1870, caused by wear in the control valve body, may be difficult to duplicate when the transmission temperature is below 93°C (200°F).

Cause
The condition may be due to wear in the control valve body. This wear occurs in the bore that contains the TCC isolator and regulator valves, and results in poor, or no, TCC apply.


Important
DTC P1870 is a type B code. The conditions for setting the P1870 DTC must occur on TWO CONSECUTIVE TRIPS (ignition cycles, with a drive cycle) before setting a P1870 history code.
When the conditions for setting DTC P1870 are met (first trip), the PCM commands maximum line pressure and harsh 1-2 shifts are the result.
This may result in a harsh 1-2 shift with no history code if the conditions for setting the DTC required for the second trip are not met, on two consecutive trips (Ignition cycles, with a drive cycle).
When the conditions for setting the DTC are met, on the second consecutive trip, a DTC P1870 is stored as a history code.
When the P1870 code is stored, the PCM will turn on the Service Engine Soon (SES), Check Engine Light (CEL), or Malfunction Indicator Lamp (MIL).

Correction
Install a control valve body with the revised TCC regulator and isolator valves. Refer to the Parts Information table below. These valves are used in all transmissions produced after January 15, 2000 (Julian Date 0015), and all of the service parts currently available through GMSPO contain revised TCC regulator and isolator valves.


Important
If all of the following conditions are true, it is not necessary to rebuild the transmission or to replace additional transmission components beyond the control valve body.

Transmission operation is normal before the transmission reaches operating temperature, or before DTC P1870 is set (no slips, flares, or missing gears).
The torque converter is not blue or overheated.
The transmission fluid is not burned or has no burned odor.
The transmission fluid pan contains no abnormal debris (clutch material, bronze, brass, or metal fragments).

--------------------------------------------------------------------------


4L60E , 4L65E Slip Condition in 2nd , 3rd or 4th Damaged 2-4 Band 3-4 Clutch - kw automatic band bind body busy chatter clutch fourth GTO second shift shudder slip third transmission valve PQC #PIP3136 - (Nov 30, 2004)
4L60E, 4L65E Slip Condition in 2nd, 3rd or 4th Damaged 2-4 Band 3-4 Clutch
.


Condition/Concern:
The 4L60E/4L65E automatic transmission may experience a condition of slipping, late or missed shifts in 2nd 3rd and 4th. An internal transmission disassembly may reveal a 2-4 band and or a 3-4 clutch being distressed.

Recommendation/Instructions:
Based on engineering transmission quality review sessions the following items should be inspected and or replaced as required. These items were found to be the cause of the distress to the 2-4 band and 3-4 clutch.

Low Line pressure (perform a PCS test as defined in SI)

1-2 accumulator piston cracked or broken

2-4 Servo Piston Seals for being cut or damaged

2-4 Servo Apply Pin for being nicked/scored /binding in the pin bore

2-4 Servo Piston Bore for being scored or mismachined

2-4 Band Anchor Pin (41) missing (low mileage)

Servo Feed Oil Passage blocked with sediment

Forward Clutch Apply Piston Seals for being cut or damaged

Forward Clutch Apply Piston for being cracked

3-4 Clutch Apply Piston Seals for being cut or damaged

3-4 Clutch Apply Piston for being cracked

3-4 Clutch and Forward Clutch oil feed passage blocked or restricted (should flow check the housing, and the passages should be inspected for proper location)

3-4 Clutch and Forward Clutch Turbine Shaft Sealing Rings for being damaged or missing

3-4 Clutch check ball (620) for leaking

3-4 Clutch air bleed orifice cup plug (698) is in place

Overrun Clutch Seal (632) damaged

#7 Checkball for not being seated or leaking

4-3 Sequence Valve (383) undersized

Boost Valve (219) stuck causing low line pressure

Input Sun Gear to Input Carrier Thrust Bearing (700) damaged came apart

Selective Washer (616) extra washer installed

Oil Pump Body (200) cracked/damaged

If none of the above items are found to be the root cause for the failure the Input Housing, Forward Clutch Piston and 3-4 Clutch Piston should be replaced and resealed as well as resealing the 2-4 Servo. Full sized trucks and utilities should have the shift cable properly adjusted and/or replaced if the cable is not holding proper adjustment. In the event the transmission as a repeat 2-4 Band or 3-4 Clutch Failure the transmission should be replaced.

------------------------------------

Deckhand

iTrader: (1)

TTT! It slipped again today from a stoplight.. feels nasty..