A/T - 325-4L Oil Pan/Sproket Cover Fluid Leaks

Bulletin No. T 84-18
File In Group 7
Number 87
Date Nov. '83

SUBJECT: 325-4L TRANSMISSION OIL LEAKS OIL PAN AND SPROCKET COVER

MODELS AFFECTED: 1982-1983 ELDORADO AND SEVILLE

Between September, 1982 and September, 1983, various changes have been made to the 325-4L transmission to alleviate oil leaks in the area of the oil pan and sprocket cover. The following is a summary of those changes by year, model and I.D. number.

FIGURE 1 - TWO ADDITIONAL HOLE POSITIONS:

1. 1982 units built after model and I.D. numbers AJ4846 and AL4609 incorporate a change in the number of bolt holes at the sprocket cover flange. Two additional bolt holes were added (refer to Figure 1).

FIGURE 2 - NEW FLANGE:

FIGURE 3 - HEX HEAD SCREW AND CONICAL WASHER ASSEMBLY:

2. 1983 units built after model and I.D. number AJ78580 and AL2837 use a new type oil pan, bolt and gasket. The new oil pan is thicker and has a raised continuous rib on the flange (refer to Figure 2). The bolts are a hex head screw and conical washer assembly (refer to Figure 3). The new gasket is thicker than previous designs.

3. Units built after model and I.D. number AJ3907 and AL1020 use a metal sprocket cover with a raised continuous rib on the flange (refer to Figure 2). Hex head screw conical washer bolt assemblies are also used along with a thick cork gasket.

When servicing 1982-1983 Eldorados and Sevilles equipped with THM 325-4L for oil leaks in these areas, it is recommended you use the listed service procedures and parts information.

Service Procedures

1. Refer to Section 7A of the 1984 Service Information Manual for the proper removal and installation procedures for the affected parts.

2. Visually inspect (A) the pan or cover and (B) the bolts to determine if the new parts have been used.

3. Assure that all new service parts are used. If new parts have been used, you should need only the new gasket.

NOTICE: A. Do not use RTV with the new type oil pan or sprocket cover.

B. Do not overtorque bolts when reassembling, split or cracked gaskets may result. Oil pan bolts should be torqued to 11 N-m (8 ft.lbs.). Sprocket cover bolts to 13 N-m (9 ft.lbs.) maximum.

C. When servicing a transmission of the earlier case design, it will be necessary to drill and tap the case to accommodate the new hole in the #1 position only. Do not drill the case in the #2 position, the area behind the case flange is a high pressure passage. If drilled too deep, case leaks may result. For case modification procedures, refer to the following steps:

1. Place the new steel sprocket cover onto the case and align the bolt holes.

FIGURE 1 - TWO ADDITIONAL HOLE POSITIONS:

2. Mark the location of the #1 hole (refer to Figure 1) onto the case flange.

3. Remove the cover and drill through the case using a No. 3 standard (.213 in.) drill bit.

4. Tap the new bolt hole using an M6 x 1.0 metric tap.

Parts Information - 325-4L

KIT NO. 8635959 KIT NO. 8635964

Qty Description P/N Qty Description P/N

1 Oil Pan 8635854 1 Sprocket Cover 8635855
1 Gasket, Oil Pan 8635884 1 Gasket, Sprocket Cover 8639726
15 Bolt Assembly 8643693 18 Bolt Assembly 8639743
1 Instruction Sheet 1 Instruction Sheet

All parts are available separately or as a kit from GMWDD.

For warranty purposes, use the following:

Oil Pan/Gasket Labor Operation Number K6500 for .5 hour.
Sprocket Cover/Gasket Labor Operation Number K7510 for 3.8 hours. ADD: If necessary
to drill and tap holes ('82 only) - .2 hour.