Low-Reverse Clutch

Place transmission in a vertical position. Ensure piston is same dimension as that removed if replacement is required. Different thickness pistons are used. Install seals on low-reverse clutch piston. Coat seals with petroleum jelly. Install piston into transmission case.
Align piston with notch in bottom of transmission case. Ensure piston is fully seated and parking pawl aligns with opening in piston wall. Install spring assembly with flat side of retainer upward. Using Spring Compressor (J-23327), compress springs past ring groove in case hub. Install retainer ring.
Remove spring compressor. Coat bearing assembly with petroleum jelly. Install bearing assembly on case hub with outside bearing race toward case hub. Install internal reaction gear and support. Install bearing assembly onto support with outside bearing race toward support. Install oil deflector (if equipped) and reaction carrier assembly in case. See Figure . Ensure clutch plates are proper thickness.

Install correct number of clutch plates. See LOW-REVERSE CLUTCH PLATE USAGE . Ensure clutch plates align with splines of reaction carrier and case and that steel plates are aligned. Place waved plate on work bench. Install 5 composition plates and 4 steel plates alternately, starting with composition plate.

LOW-REVERSE CLUTCH PLATE USAGE

Type	No. Used	Thickness: In. (mm)
Flat Steel	4	.069 (1.75)
Composition	5	.088 (2.24)

Install low-reverse support. Apply light pressure to low-reverse support. DO NOT apply excessive pressure or waved plate will start to flatten, resulting in inaccurate measurement. Measure height of clutch pack from work bench to top of low-reverse support. Using height dimension, determine proper selective spacer plate to be used. See SPACER PLATE SELECTION .

SPACER PLATE SELECTION

Measured Clutch Pack Height In. (mm) ⁽²⁾

⁽¹⁾ Plate Thickness In. (mm)

1.136-1.164 (28.85-29.57)

.066-.073 (1.67-1.85)

1.107-1.136 (28.12-28.85)

.094-.101 (2.39-2.57)

1.079-1.107 (27.41-28.12)

.122-.129 (3.10-3.28)

⁽¹⁾	Spacer plates are available in select sizes. Plate (8680439) has no identifying marks and is .066-.073" (1.67-1.85 mm) thick. All other plates have same GM part number (8680440) but are different thicknesses and have one of following stamped identifying marks: "0", "4" or "8".

⁽²⁾	Clutch pack height is measured without spacer plate in position.

Place spacer plate between waved plate and first composition clutch plate with identification facing upward. Measure overall height of clutch pack. Overall height should be 1.20-1.24" (30.5-31.5 mm). Install clutch pack assembly in transmission case.
Install low-reverse support in case with hub downward. Install inner race by pushing downward while rotating until it is fully engaged. Bottom tangs will be flush with hub when fully installed. Install spring retainer in case between case lug and open notch in support. Install low-reverse retainer ring.