Servicing - A/t GMC Sonoma Syclone

IDENTIFICATION

TRANSMISSION APPLICATION

Transmission

Check transmission fluid level at each engine oil change. On vehicles under 8600 Gross Vehicle Weight Rating (GVWR), change transmission fluid and filter at 30,000 mile intervals. On vehicles over 8600 GVWR, change transmission fluid and filter at 24,000 miles.

If vehicle is used in severe service conditions (commercial use, trailer pulling, constant stop-and-go driving), change fluid and filter every 15,000 miles on vehicles under 8600 GVWR and at 12,000 miles on vehicles over 8600 GVWR.

Transfer Case

Check transfer case lubricant every oil change or every 12 months. Check more frequently under severe conditions.

CHECKING FLUID LEVEL

Note. Vehicle must be at normal operating temperature when checking fluid level. One pint of fluid raises level from ADD to FULL mark on dipstick in a hot transmission. DO NOT overfill.

With vehicle parked on a level surface and engine at idle, move selector lever through all positions, ending in Park. Remove dipstick, wipe clean and check fluid level. Fluid level should be between ADD and FULL marks on dipstick.

If vehicle has been operated for an extended time at high speed, in city traffic, or pulling a trailer, an accurate fluid level cannot be immediately determined. Transmission must cool for about 30 minutes after vehicle is parked before fluid level can be accurately checked.

Remove fill plug. Check oil level. If level is not up to fill plug opening, add lubricant until it is.

RECOMMENDED FLUID

Transmissions and transfer cases use Dexron-II ATF.

Transfer Case & Transmission

The transmission refill capacities are approximate. See TRANSMISSION REFILL CAPACITIES and TRANSFER CASE REFILL CAPACITIES . Determine correct fluid level by marks on dipstick. DO NOT overfill transmission.

TRANSMISSION REFILL CAPACITIES

TRANSFER CASE REFILL CAPACITIES

1. Raise and support vehicle. Loosen transmission oil pan bolts. Slowly pry pan loose with a large screwdriver and allow fluid to drain. Remove oil pan and gasket. Remove filter or filter screen. Replace paper element filter (if used).
2. Clean filter screen (if equipped) and pan with solvent. Blow dry with compressed air. Install oil pan with new gasket.
3. Add 3 quarts of Dexron-II. Start engine and recheck level. Add fluid until level is between FULL and ADD marks on dipstick. Test drive vehicle and recheck fluid level.

Remove drain plug from transfer case. Remove fill plug for easier draining. With fluid fully drained, reinstall drain plug. Fill transfer case to fill plug opening with Dexron-II.

HYDRA-MATIC 4L60 (THM 700-R4)

Depress readjust tab on cable adjuster and hold. (Scheme 358) Move slider back through fitting away from throttle body lever until slider stops at fitting. Release readjust tab and open throttle body lever to full throttle stop. This automatically adjusts slider to correct setting.

Scheme 358

Diesel

1. Loosen vacuum regulator valve-to-injection pump bolts enough to allow for regulator valve rotation. Attach vacuum pump to bottom vacuum port of valve (vacuum gauge to top port). (Scheme 359)
2. Insert.646" (16.4 mm) Gauge Block (J-33043) between gauge boss on injection pump and wide open stop screw on throttle lever. Rotate throttle shaft against block.
3. Apply 18-21 in. Hg vacuum to VRV. Slowly rotate VRV body clockwise (facing valve) until vacuum gauge reads 10.9-12.1 in. Hg. Hold valve body in this position and tighten mounting screws. NOTE: Set valve while rotating in a CLOCKWISE direction only.
4. Check adjustment by allowing throttle shaft to return to idle position, then rotate shaft back against gauge block. If vacuum gauge reading is not 10.9-12.1 in. Hg, readjust valve.
5. With vacuum regulator valve vacuum set, confirm detent switch point by reading resistance between ignition terminal and detent terminal. Attach an ohmmeter across ignition terminal (Pink/Black wire) and detent terminal (Orange wire).
6. Insert Gauge Bar (J-36142) between gauge boss on pump and wide open stop screw on throttle shaft. (Scheme 359) Rotate and hold throttle lever against gauge bar. There should be no continuity (infinite resistance).
7. Release throttle lever and allow it to return to idle position. Remove gauge bar. Rotate throttle lever to Wide Open Throttle (WOT) position. Check switch for continuity. There should be continuity before throttle reaches WOT position. If switch does not meet specification, return to step 1).

Scheme 359

Lumina APV, Silhouette & Trans Sport

1. To adjust shift cable, place shift lever in Neutral. Turn transaxle lever clockwise from Park through Reverse to Neutral.
2. Place shift control assembly in Neutral position. Push tab on cable adjuster to adjust cable in cable mounting bracket.

Except Lumina APV, Silhouette & Trans Sport

1. Ensure shift tube and lever are free in steering column. To adjust linkage, remove screw and spring washer from swivel. Turn transmission lever clockwise to stop, then counterclockwise 2 detents. This is Neutral position.
2. Place selector lever in Neutral. Locate proper position using mechanical stops, NOT shift indicator pointer. Hold swivel against shift lever. Install spring washer and screw and tighten finger tight. Avoid applying force in either direction (along shift rod or lever) while tightening screw to 17 ft. lbs. (23 N.m).

Column-Mounted Switch

1. Place gearshift selector lever in Neutral, and loosen switch attaching screws. Rotate switch on column until a 3/32" (2.5 mm) drill bit will insert into switch gauge hole to a depth of .4" (10 mm).
2. Tighten switch attaching screws and remove gauge pin. Check for engine starting in Neutral and Park only.

Transmission-Mounted Switch

1. Raise and support vehicle. Loosen neutral safety switch mounting bolts. Align hole in switch lever with hole in switch assembly. Insert a 3/32" (2.5 mm) drill bit through switch holes to hold switch in Neutral.
2. With selector lever on transmission in Neutral detent position, tighten switch mounting bolts and remove gauge pin. Lower vehicle and check switch operation, ensuring vehicle will NOT start in any forward or reverse gear.

Identifying Hydra-Matic 3T40 (THM 125-C) Oil Pan Gasket. Scheme 360

Identifying Hydra-Matic 3L30 (THM 180-C) Oil Pan Gasket. Scheme 361

Identifying Hydra-Matic 4L80-E Oil Pan Gasket. Scheme 362

Identifying Hydra-Matic 4L60 (THM 700-R4) Oil Pan Gasket. Scheme 363

See also:
• TRANSMISSION REFILL CAPACITIES