SUBJECT: EXTRACTS FROM SERVICE LETTER SEPT. 1, 1976 — GROUP 7B
MODELS: HOLDEN HX, WITH TRIMATIC TRANSMISSION
SERVICE OPERATIONS-SERIES 3 TRIMATIC TRANSMISSION
- Raise the vehicle on a hoist or place on jack stands.
- Remove the drain plug frorn the oil pan and allow the oil to drain into a container.
- Remove the oil pan attaching bolts and oil pan.
- Remove the servo cover altaching bolts and servo cover.
- Loosen adjusting screw lock nut.
- Using tool 7AT4 and torque wrench, tighten adjusting screw to 4.5 Nm (40 Lbs. Ins).
- Back off screw exactly five (5) turns for all Transmission Codes except KK & KX calibration "B".
- On KK & KX calibration "B" codes the back-off is exactly six (6) turns.
- Tighten lock nut and install servo cover and oil pan.
- Refill transmission with Dexron fluid.
CAUTION: After A long run the oil will be hot enough to cause serious burns, therefore, suitable precautions must be taken.
Series 3 Trimatic Transmissions: Series 3 Trimatic Transmissions are defined as those which incorporate a number of design refinements and are released on the above vehicles simultaneously with the introduction of engines designed to meet the requirements of ADR 27A (Emission Control).
The following series 3 Transmissions are released for HX and LX Series Vehicles. Ø
* The only difference between Codes KK and KX is in the speedometer drive gear used. Refer specifications section for details. KK & KX Codes could be either calibration "A" or "B", differences between these calibrations are covered in this item.
The principles of operation of Series 3 Trimatics are covered in the Series 3 "Trimatic Automatic Transmission Service Manual" - Volume 1, Part Number M 37823, (available through G.M.P. & A. outlets.) Overhaul procedures are covered in the "Series 3 Trimatic Automatic Transmission Service Manual" - Volume 2 - ''Service Operations", and diagnosis in the "Series 3 Diagnosis Guide" - Volume 3. These latter two publications will be released shortly.
The following new features are common to all Series 3 Transmissions.
- Revised 1-2 and 2-3 shift trains.
- Revised low speed timing valve.
- Revised 3-2 control valve.
- Deletion of the oil pump priming valve.
- Deletion of the second clutch dump ball valve.
- Revised line pressure filter for the governor.
- The use of boosted line pressure in "S" range.
- Use of a third clutch cushion plate in all Transmission Codes.
- Revised accumulator piston pin.
- Revised transfer plate and gaskets.
- Deletion of transfer plate to valve body bolts.
For details of operation of the new shift trains, 3 – 2 control and low speed timing valves, refer to the Series 3 "Service Manual" - Volume 1.
** Refer the item on Page 20 of this group for details of Trimatics used with the 5.0 litre and Gemini 1600 engines.
In addition to the new features common to all Series 3 Transmissions, there are some differences between the various Series 3 Transmission Codes. The following summarizes the differences between the various codes.
TCS Switch: The TCS switch for the vacuum advance control system is used in all Series 3 Trimatics except Code KY (1900). On Code KY the unused TCS switch mounting hole is blocked with a plug.
Valve Body Assemblies: Revisions have been made to the oil passages in the valve body to provide boosted line pressure in "S" intermediate range. Valve bodies incorporating the revised passages can be identified by the letter "E" cast in the line pressure port at the manual valve.
Valve body application can be identified by the last three digits of the Production (not service) part number stamped on the underside of the valve body on the ground surface adjacent to the accumulator piston pin. This area also carries a letter to indicate the valve body calibration. Series 3 valve bodies carry the following application identification.
Transfer Plate: The transfer plate part number is stamped in the area shown in Fig. 1. The following part numbers apply for Series 3 Transmissions.
Appropriate changes have also been made to the transfer plate gaskets.
Vacuum Modulator Valve and Sleeve: The Fig. 2 identifies modulator valve and sleeve application in Series 3 Trimatics.
Governors: The light weight, 4 cylinder type governor primary valve is used in all Series 3 governors. Codes KK, KX, KJ, and KH use the heavier governor secondary valve, KY Codes use the lighter 4 cylinder type secondary valve.
For details of torque converters, speedometer drive gears and clutches, refer "Specifications" at the rear of this item. For spring details refer "Spring identification chart"; shift speeds refer the "Shift Speed Chart" and line pressure check refer the "Line Pressure Specification Chart" all at the rear of this item.
Transmission Removal and Installation: Transmission removal and installation procedures are essentially the same as for HJ and LH. However the TCS switch lead must be removed from the switch and retaining clip prior to removing the transmission. (refer Fig. 3).
Line Pressure Checks: Experience has shown that incorrect line pressure has a cumulative undesireable effect on many transmission operations.
Line pressure should be checked with an accurate pressure gauge (tool No. HM1844 or similar) connected into the pressure tapping on the left hand side of the transmission case. Checks must be made with the transmission at stabilized operating temperature after first ensuring that the fluid level is correct.
Stabilized operating temperature is not attained until the transmission fluid has reached 80° to 88°C. This temperature is not achieved until the vehicle has covered at least 16 km of stop/start operation.
Three pressure checks are used for diagnosis and operational checks of the Trimatic transmission. Checks 1 and 2 are made with the vacuum modulator pipe connected to the inlet manifold and the vehicle coasting on over-run. This is necessary to ensure that the modulator is having no effect on line pressure. Check number 3 cannot be performed with the vehicle moving because of the effect of governor pressure on the modulator valve which reduces modulator pressure and line pressure. Check number 3 must therefore be carried out with the vehicle stationary under a "light stall" condition at 1200 engine R.P.M.
NOTE: Since check number 3 involves a partial stall test it must be carried out with due regard to safety. This check should be conducted as part of the road test with the vehicle in the open. Even a partial stall test can be potentially dangerous if conducted in a workshop because of the possibility of the vehicle inadvertently moving with the danger of injury to personnel or damage to property.
Check number 3 should be conducted as quickly as practicable. Do not hold 1200 engine R.P.M. for longer then ten (10) seconds since fluid in the converter may overheat and cause damage to the converter housing oil seal.
The purpose of check number 1 is to determine minimum line pressure at a given engine speed when the regulator valve and spring are the controlling factors. Check number 2 introduces the boost valve to check the boost circuit and check number 3 simulates full throttle operation in 'D' range by having full modulator pressure operating on the boost valve to check the modulator circuit at a given engine speed.
- Connect the pressure gauge into the line pressure tapping in the left hand side of the transmission case.
- Install a tachometer to the engine. Set tachometer to the 5000 R.P.M. scale.
- Thoroughly warm transmission and check fluid level.
- Conduct checks 1, 2, and 3 and note readings.
LINE PRESSURE SPECIFICATION CHART
|CHECKS||PRESSURE k.P.a. (P.S.l.)|
|Code KJ (3300)||Code KK & KX (4.2)||Code KH 2850||Code KY 1900|
CHECK NO. 1
Line Pressure in 'D' Range (Vacuum Modulator Pipe Connected) Vehicle coasting between 55-50 km/h
CAL "A" 393-434 (57-63)
CAL "B" 324-365 (47-53)
|324-366 (47-53)||324-366 (47-53)|
CHECK NO. 2
Line Pressure in "S" and "L" Ranges (Vacuum Modulator Pipe Connected) Vehicle coasting between 40-30- km/h
|531-614 (77-89)||CAL "A" & "B" 648-730 (94-106)||531-614 (77-89)||531-614 (77-89)|
CHECK NO. 3*
Line Pressure in 'D' Range (Vacuum Modulator Pipe Disconnected). 1200 R.P.M. engine speed-foot and park brake applied
|903-978 (131-142)||CAL "A" & "B" 972-1068 (141-155)||809-882 (117-128)||809-882 (117-128)|
* During Check No. 3 with the vacuum modulator pipe disconnected, the manifold connector must be plugged to prevent an excessive air leak into the manifold.
NOTE: When the three checks have been completed, let the engine idle in "D" range and note the idle line pressure. If the reading is no more than 34.5 kPa (5 P.S.I.) below the reading obtained in Check No. 1 the pressure can be considered satisfactory. If the reading is more than 34.5 kPa (5 P.S.I.) below that obtained in Check No. 1 it indicates a jammed regulator valve or poor pump out-put due to excessive gear clearance etc. and/or excessive internal leakage in the transmission. Any of these conditions will require further investigation.
When assessing the results of Check No. 2, a situation may be encountered where the line pressure obtained during coast operation is satisfactory, but the line pressure in "S" & "L" ranges with the engine idling is significantly below the value obtained during the check on the road. This condition is due to the lower pump speed at engine idle coupled with some possible fluid loss in the third clutch circuit.
As a guide, if the line pressure in "S" & "L" at engine idle with the transmission hot does not fall below the value obtained in "D" range during Check No. 1, then the oil pump body bushing can be considered serviceable and should not be replaced.
Pressure Regulator Boost Valve and Sleeve: Codes KJ, KH, KY and "A" calibration KK & KX use boost valve P/N 5258143 and sleeve 5258161.
Codes KK & KX, "B" calibration, use boost valve P/N 9945355 and sleeve 9945354. Refer Fig. 4 below for identification details of boost valves.
Servo Piston: In codes KK & KX, "B" calibration, the servo piston is revised in that the length of the centre boss has been reduced by approximately 1.5 mm (.060 in) and is now level with the top of the piston, refer Fig. 5. This revision was made to increase the "cushion" stroke of the piston.
Second Clutch Pack Clearance: Series 3 Trimatics may be found to have one additional driven (steel) plate in the second clutch. This plate is used to maintain the plate pack clearance to between .381 mm (.015 in) and 2.286 mm (.090 in). When assembling second clutches with the additional steel plate, the plate should be installed next to the spacer.
If the additional plate was not originally installed, and the plate pack clearance is in excess of 2.286 mm (.090 in.) it is permissible to add an additional plate in service, provided that by doing so the clearance does not fall below .381 mm (.015 in.).
CAUTION: The recommendation for controlling plate pack clearance applies to the second clutch only. The clearance check does not apply to the reverse and third clutches.