Drive Axle - 7.5" - 9.5" GMC Jimmy Typhoon

MODEL IDENTIFICATION

Vehicle model can be identified by fifth character of Vehicle Identification Number (VIN), stamped on metal pad on top of left end of instrument panel, near windshield. See MODEL IDENTIFICATION table.

MODEL IDENTIFICATION

AXLE RATIO & IDENTIFICATION

To identify vehicle differential ring gear size and drive axle ratio, see DRIVE AXLE RATIO IDENTIFICATION article in the DRIVE AXLES Section.

DESCRIPTION

Note. 8 1/2" ring gear differential is also used as front drive axle on K15/25 models. K15/25 models may also be equipped with a Dana front drive axle. See DRIVE AXLE - DANA FULL-FLOATING article in the DRIVE AXLES Section.

Note. Some models are equipped with limited-slip or locking differentials. For testing and overhaul procedures for these units, see DRIVE AXLE - EATON LOCKING DIFFERENTIAL TYPE article in the DRIVE AXLES Section.

Drive axle assembly is hypoid gear type with integral carrier housing. This type assembly is used on Light Duty emission vehicles with semi-floating axles. Differential side bearing preload adjustment and drive pinion depth adjustment are made by using shims. Pinion bearing preload is made with a collapsible spacer.

A removable differential cover permits inspection and minor servicing of differential without removing axle assembly from vehicle. Service procedures are same for all assemblies, except for torque specifications and special tool numbers. Astro and Safari use 7 5/8" ring gear. "S" and "T" Series use 7 1/2" and 7 5/8" ring gears. All other models use 8 1/2" and 9 1/2" ring gears.

LUBRICATION

Fill differential with 80W or 80W-90 GL-5 gear lubricant to 1/4" (6 mm) below edge of filler hole. On models equipped with limited-slip or locking differentials, add 4 ozs (.12 L) of limited slip additive.

TROUBLE SHOOTING

Note. See TROUBLE SHOOTING - BASIC PROCEDURES article in the GENERAL TROUBLE SHOOTING section.

Scheme 19

Scheme 20

Scheme 21

1. Raise vehicle and support. Remove rear wheels and brake drums. Place drain pan below differential cover. Loosen but do not remove differential cover bolts. Break cover loose and catch lubricant in drain pan. Remove differential cover bolts and remove cover. Remove differential pinion shaft lock bolt.
2. On non-locking differential drive axle assemblies (without thrust block and clutch packs), remove differential pinion shaft. Push outer flanged end of axle shaft toward center of vehicle. Remove "C" lock from axle shaft groove and from counterbore recess in side gear. Remove axle shaft from axle housing.
3. On locking differential drive axle assemblies (with thrust block and clutch packs), partially remove pinion shaft from differential case. Rotate differential case until pinion shaft touches edge of carrier housing. (Scheme 19)
4. Reach into case using screwdriver and rotate "C" lock until its open end points directly inward toward thrust block and "C" lock is aligned with thrust block sides. (Scheme 20) When "C" lock is correctly positioned, push outer flanged end of axle shaft toward center of vehicle. This will move "C" lock out of counterbore recess in side gear and allow it to be removed from thrust block and from axle shaft groove. Remove axle shaft from axle housing. (Scheme 20) CAUTION: DO NOT hammer on axle shaft flange. Axle shaft should slide inward easily when "C" lock is correctly aligned with thrust block. When removing pinion shaft from differential case on 9 1/2" ring gear axle, be sure pinion gear thrust washer does not slip out.
5. On all assemblies, with axle shaft removed, insert Axle Bearing & Seal Remover (J-22813-01 ) for 7 1/2" and 7 5/8", (J-23689 ) for 8 1/2" or (J-29712 ) for 9 1/2" ring gears into axle housing behind bearing. Attach Slide Hammer (J-2619 ) and Adapter (J-2619-4 ) for 7 1/2" and 7 5/8" or (J-2619-01 ) for 8 1/2" and 9 1/2" ring gears to bearing remover. Remove axle bearing and axle seal. (Scheme 21) CAUTION: On "S" Series with 7.5" ring gear, 2 different replacement seal/bearing assemblies are available. These assemblies are not interchangeable.

Scheme 22

1. On "S" Series with 7.5" ring gear assembly, there are 2 different seal/bearing assemblies available that are not interchangeable. If axle code fourth digit is a "K", use part numbers 26029139 (seal) and 26024326 (bearing kit). If axle code fourth digit is a "C", use part numbers 26029137 (seal) and 26023822 (bearing kit). (Scheme 22)
2. Using Bearing Installer (J-23765 ) for 7.5" ring gear, install axle shaft bearing into housing until bearing installer bottoms against housing shoulder. Using Seal Installer (J23771 ), on "K" axle models, install axle shaft seal into housing until seal is flush with outer edge of axle tube. (Scheme 22) On "C" axle models, install axle shaft seal into housing until seal outer flange seats itself with outer edge of axle tube.
3. Install axle shaft and "C" lock. Pull axle shaft outward to seat "C" lock into side gear counterbore recess. Install pinion shaft and pinion shaft lock bolt. Tighten bolt to specification. See «TORQUE SPECIFICATIONS»(/gmc/jimmy-typhoon/1992-1993/remont/differentials-drive-axles/#drive-axle-75-95) table. To complete installation, reverse removal procedure.

Installation (Except "S" Series)

1. Using Bearing Installer (J-23765 for 7 1/2" and 7 5/8", J-23690 for 8 1/2" or J-29709 for 9 1/2" ring gears), install axle shaft bearing into housing until bearing installer bottoms against housing shoulder.
2. Using Seal Installer (J-23771 ) for 7 1/2" and 7 5/8", (J-21128 ) for 8 1/2" or (J-29713 ) for 9 1/2" ring gears, install axle shaft seal into housing until seal is flush with outer edge of axle tube. Install axle shaft and "C" lock. Pull axle shaft outward to seat "C" lock into side gear counterbore recess.
3. Install pinion shaft and pinion shaft lock bolt. Tighten lock bolt to specification. See «TORQUE SPECIFICATIONS»(/gmc/jimmy-typhoon/1992-1993/remont/differentials-drive-axles/#drive-axle-75-95) table. To complete installation, reverse removal procedure.

PINION FLANGE & OIL SEAL

Note. If replacing pinion and ring gear, discard original pinion flange after removal. Replacement pinion, ring gear and pinion flange are balanced as an assembly.

Scheme 23

1. Raise vehicle and support. Allow rear hub and carrier assembly to hang free. Remove drive shaft from pinion flange. Wrap tape around all "U" joint caps to retain caps in place. Position drive shaft out of way.
2. Using an INCH-pound torque wrench with proper size socket connected to pinion flange nut, rotate pinion several revolutions. Stop and start rotation several times to note and record pinion bearing preload.
3. Ensure relationship of pinion-to-pinion flange nut-to-pinion flange is marked for reassembly purposes. Count and record number of exposed threads on pinion.
4. Hold pinion flange with Companion Flange Holder/Remover (J-8614-01 or J-8614-1 ). (Scheme 23) Remove pinion self-locking nut. Install Pinion Flange Remover (J-8614-1, J-8614-2 and J-8614-3 ) through companion flange holder and remover. Tighten pinion flange remover. Remove pinion flange from pinion. Pry pinion seal from housing. DO NOT damage differential carrier or seal running surface on pinion when removing pinion seal. CAUTION: DO NOT hammer flange onto pinion shaft to install, as ring gear and pinion will be damaged.

Installation

1. Inspect pinion flange oil seal surface, drive splines, flange ears and bearing contact surface. Replace pinion flange if damaged. Lubricate inside diameter of seal. Place pinion seal in housing bore.
2. Using Seal Installer (J-23911 for 7 1/2" and 7 5/8" ring gears, J-23836 for 8 1/2" ring gear or J-22388 for 9 1/2" ring gear), install pinion seal into bore until seal is flush with outer edge of housing. Ensure oil seal is square in housing.
3. Install a non-hardening sealer to pinion splines or internal splines of pinion flange. Install flange on pinion shaft, aligning scribe marks made previously. If required, use only soft-faced (rubber) hammer to tap flange onto pinion.
4. Install washer and self-locking nut to pinion, and snug tighten, taking note of scribe marks and number of exposed threads. Measure pinion preload. Using companion flange holder and remover, and socket/torque wrench assembly, tighten self-locking nut in small increments. Measure pinion preload until preload exceeds original figure by 3-5 INCH lbs. (.3-.6 N.m). If preload exceeds specification, remove pinion and replace collapsible sleeve. Install drive shaft. Add gear oil as needed.

Removal & Installation

1. Raise vehicle and support at frame. Allow rear hub and carrier assembly to hang free. Drain lubricant. Remove rear wheels and brake drums. Remove parking brake cable. Disconnect drive shaft and brake lines. Disconnect vent hose from vent fitting on axle housing. Support axle housing using floor jack under center of carrier assembly. Disconnect height sensing and brake proportional valve linkage (if equipped).
2. Disconnect shock absorbers at axle housing. Remove stabilizer shaft (if equipped) from housing. Remove "U" bolt nuts, washers, spacers and spring plates from axle assembly. Note angle position of wedge type spring plates (if equipped). Slowly lower floor jack. Remove axle assembly from vehicle.
3. To install rear hub and carrier assembly, reverse removal procedure. Bleed brake system. Adjust height sensing and brake proportional valve linkage (if equipped).

DIFFERENTIAL ASSEMBLY

Note. Check and record ring gear backlash and pinion bearing preload before disassembly.

Disassembly

1. Remove axle shafts. See «AXLE SHAFT & BEARING»(/gmc/jimmy-typhoon/1992-1993/remont/differentials-drive-axles/#drive-axle-75-95) under REMOVAL & INSTALLATION. Roll out differential pinions and thrust washers. Mark pinions and thrust washers (left and right) for reassembly purposes. Remove side gears and thrust washers. Mark side gears and thrust washers (left and right) for reassembly purposes.
2. Mark differential case side bearing caps and housing for reassembly reference. Loosen bearing cap bolts and tap bearing cap surfaces to loosen caps. Remove caps, mark shims, spacers, and side bearing races. Using pry bar inserted into differential case, pry against housing at differential window to remove case. CAUTION: Differential case side bearings are preloaded. Differential case will fall free after being pried past a certain point.
3. After removing differential case, place loose shims with appropriate left and right bearing races. Using Differential Side Bearing Puller/Remover (J-22888 ) and Adapter (J-8107-2 ) for 7 1/2" and 7 5/8" ring gears, (J-8107-4 ) for 8 1/2" or (J-8107-3 ) for 9 1/2" ring gears, remove differential case side bearings. DO NOT pull on bearing cage, pull on bearing cone.
4. Ring gear bolts have left-hand threads. Remove ring gear bolts. Tap ring gear off carrier using a soft drift and hammer. Using an INCH lb. torque wrench and proper socket, check torque required to rotate drive pinion. If no preload reading is obtained, check for looseness of pinion assembly. Looseness indicates pinion bearings and collapsible sleeve should be replaced.
5. Remove pinion flange. See «PINION FLANGE & OIL SEAL»(/gmc/jimmy-typhoon/1992-1993/remont/differentials-drive-axles/#drive-axle-75-95__pinion-flange-oil-seal) under REMOVAL & INSTALLATION. Install pinion nut back onto pinion. Install rear differential cover using 2 bolts to keep pinion from falling out. Tap end of pinion (using soft drift and hammer) to remove pinion from front bearing. CAUTION: Use care not to damage pinion bearings when removing pinion from differential housing.
6. Remove differential cover and pinion assembly. Remove pinion oil seal and front bearing from housing. Remove collapsible spacer from pinion. Remove inner bearing from pinion using a press and Bearing Remover Clamp (J-25320 for 7 1/2" and 7 5/8", J-8612-B for 8 1/2" or J-22912-01 for 9 1/2" ring gears). Press bearing from pinion, and remove shim.
7. Remove pinion bearing races from axle housing using hammer and punch. Inspect bearings and bearing races. Replace as required. Discard and replace pinion oil seal, pinion self-locking nut and collapsible spacer.

Cleaning & Inspection

Clean all parts in cleaning solvent. Inspect all bearings and races for chipping, cracks, brinelling or excessive wear. Inspect axle shaft splines, ring gear and pinion teeth for scoring, cracking or chipping. Inspect differential case side gears, thrust washers and pinion shaft for cracks or excessive wear. Inspect pinion flange oil seal surface, drive splines, flange ears and bearing contact surface. Replace components as required.

Reassembly

1. If installing new ring gear and pinion, and/or pinion bearings, see «DRIVE PINION DEPTH»(/gmc/jimmy-typhoon/1992-1993/remont/differentials-drive-axles/#drive-axle-75-95) and «SIDE BEARING PRELOAD»(/gmc/jimmy-typhoon/1992-1993/remont/differentials-drive-axles/#drive-axle-75-95__side-bearing-preload) under ADJUSTMENTS. After installing original pinion shims onto pinion, install inner pinion bearing onto pinion using Bearing Installer (J-5590 ). Drive bearing onto pinion until bearing is tightly seated against pinion shims.
2. Install a NEW collapsible spacer onto pinion. Lubricate pinion bearings. Install pinion into axle housing. Install outer bearing onto pinion using Bearing Installer (J-5590 ). Hold pinion in position inside housing while driving bearing onto pinion. To install pinion oil seal and pinion flange, see «PINION FLANGE & OIL SEAL»(/gmc/jimmy-typhoon/1992-1993/remont/differentials-drive-axles/#drive-axle-75-95__pinion-flange-oil-seal) under REMOVAL & INSTALLATION.
3. Install ring gear squarely onto differential case. Tighten ring gear bolts evenly and alternately to specification. Ring gear bolts are left-hand thread. See «TORQUE SPECIFICATIONS»(/gmc/jimmy-typhoon/1992-1993/remont/differentials-drive-axles/#drive-axle-75-95) table.
4. Lubricate pinion gears and side gears with gear oil. Install left and right gears and thrust washers into case as marked in disassembly. Install one pinion gear onto side gears and rotate gears until pinion gear is exactly opposite. Place second pinion gear onto side gears so that pinion gear holes are exactly opposite each other.
5. Verify pinion shaft fits through both pinion gears for alignment purposes. Install pinion gear thrust washers. Hold pinion gears in position and carefully remove pinion shaft. Rotate side gears to position pinion gears in alignment with differential case holes. Install pinion shaft and pinion shaft lock bolt. Temporarily snug tighten lock bolt.
6. If side bearings were removed, install side bearings to differential case using Press or Bearing Installer (J-25299 ). Using Bearing Installer (J-25299 ), first install Adapter (J-8107-2 ) to opposite bearing end of differential case to protect case surface. Drive bearing onto case using hammer, Bearing Installer (J-25299 ) and Adapter (J-8092 ). Repeat for opposite side.
7. Lubricate side bearings and install races. Install differential case into carrier housing. Install spacer between each bearing race and housing with chamfered edge of spacer against housing. Install right bearing cap and loosely tighten bolts so that differential case is free to move but will not fall out of housing. To complete installation, see «SIDE BEARING PRELOAD»(/gmc/jimmy-typhoon/1992-1993/remont/differentials-drive-axles/#drive-axle-75-95__side-bearing-preload) under ADJUSTMENTS.

Scheme 24

1. Drive pinion rear bearing shim thickness must be determined whenever a new axle housing, ring gear and pinion, or pinion bearings is installed. Shim pack thickness is determined by using Pinion Setting Gauge Set (J-21777 ). (Scheme 24)
2. Install pinion bearing races into housing (if previously removed). Install lubricated rear pinion bearing through rear of housing. Position Gauging Plate (J-23597-11 for 7 1/2" and 7 5/8", J-21777-29 for 8 1/2" or J-21777-85 for 9 1/2" ring gears) to rear pinion bearing. Install stud bolt and washer through gauging plate and rear pinion bearing, pointing stud bolt toward front pinion bearing position. (Scheme 24)
3. Install lubricated front pinion bearing into race. Install Bearing Disc (J-21777-42 ) to outside of front pinion bearing. Install and tighten stud bolt hex nut until snug. Rotate gauge plate and bearings to insure proper seating, while snugging hex nut. Hold stud bolt head stationary with a wrench. Using INCH lb. torque wrench, tighten hex nut in small increments until 20 INCH lbs. (2.2 N.m) of torque is required to rotate gauge plate and bearings. (Scheme 24)
4. Mount side bearing Gauging Discs (J-21777-45 ) for 7 1/2", 7 5/8" and 8 1/2" ring gears or (J-21777-86 ) for 9 1/2" ring gear on ends of arbor. Place arbor into carrier side bearing recesses making sure gauging discs are properly seated. Install side bearing caps and bolts. Snug tighten bolts to avoid arbor movement.
5. Position dial indicator on mounting post of arbor with contact button resting on top surface of plunger. Set dial indicator to zero. Push indicator down on indicator shaft until needle rotates 3-4 revolutions to right, and then tighten in this position.
6. Place plunger onto gauging area of pinion gauge plate. Rock plunger rod slowly back and forth across gauging area until dial indicator reads greatest deflection.
7. At point of greatest deflection, set indicator to zero. Repeat rocking action several times to verify setting. Once zero reading is obtained, rotate gauge shaft to remove plunger from gauging area.
8. Dial indicator will now read required pinion shim thickness for nominal pinion setting. Record this reading. Check drive pinion for painted or stamped markings on pinion stems, or for a stamped code number on small end of pinion gear.
9. If marking is a plus (+), add that many thousandths of an inch to recorded indicator reading. If marking is a minus (-), subtract that many thousandths of an inch from indicator reading. This measurement will then be required thickness of rear pinion bearing shim pack. NOTE: If no markings are found on pinion, use dial indicator reading as shim thickness.
10. Remove bearing caps and all gauging tools from housing. Place selected shim pack on pinion gear. Using a press, install lubricated pinion bearing onto pinion shaft.
11. Install a NEW collapsible spacer over pinion gear shaft. Install pinion assembly into position from rear of housing. While holding pinion in position, carefully drive front pinion bearing onto pinion gear shaft until a few threads are exposed.
12. Install pinion seal, pinion flange, washer and nut. Ensure pinion flange alignment mark is properly aligned with pinion shaft end mark. Using Companion Flange Holder/Remover (J-8614-01 ), tighten pinion self-locking nut until all end play is removed. Rotate pinion several times to seat bearings. Check preload using an INCH-pound torque wrench.
13. Continue tightening nut and checking preload until specified preload is obtained. See «AXLE ASSEMBLY SPECIFICATIONS»(/gmc/jimmy-typhoon/1992-1993/remont/differentials-drive-axles/#drive-axle-75-95) table. DO NOT back off nut to lessen preload.
14. If preload is exceeded, install a NEW collapsible spacer and retighten self-locking nut until proper preload is obtained.

SIDE BEARING PRELOAD

Note. Adjust drive pinion depth prior to performing side bearing preload adjustment.

Scheme 25

1. Side bearing preload and backlash adjustment are adjusted by varying thickness of both left and right side bearing shims. Side bearings must be previously installed to differential case. Lubricate side bearings and install races.
2. Place differential case assembly into position in housing. Position ring gear tightly against pinion so backlash is.000-.001" (0-.025 mm). Hold assembly in place by hand temporarily. Install Bearing Strap (J-22799-6 ) to left side bearing race.
3. Install Side Bearing Backlash Gauge (J-22779 ) between left side bearing race and carrier housing. (Scheme 25) While moving gauge up and down, tighten gauge adjusting nut until a slight drag is felt. Tighten lock bolt on side of gauge, and leave gauge in position.
4. Install service adjustment spacer and shim between right bearing race and carrier housing. Determine bearing preload by inserting progressively larger feeler gauges between carrier and shim. The point just before feeler gauge drag begins is the correct feeler gauge thickness. This is the zero setting without preload.
5. Remove gauge from left side. Using a micrometer, measure gauge in 3 places and average readings. Record measurements.
6. Add together measurements of right side shim, spacer and feeler gauge. Subtract.010" (.25 mm) from ring gear (left) side measurement and add.010" (.25 mm) to opposite (right) side measurement. This allows for initial backlash adjustment.
7. To obtain correct preload, add.004" (.10 mm) to both measurements. Total measurement is correct shim pack thickness for each side. Example: Ring Gear Side (Left) Shim Pack.250" (Gauging Tool Measurement) -.010" (Backlash Adjustment) +.004" (Bearing Preload) =.244" (Ring Gear Side Shim Pack) Example: Opposite Ring Gear Side (Right) Shim Pack.265" (Combined Measurement Total) +.010" (Backlash Adjustment) +.004" (Bearing Preload) =.279" (Opposite Ring Gear Side Shim Pack) NOTE: If shim is not chamfered enough and scrapes spacer when it is installed, file or grind chamfer before installation.
8. Install ring gear side shim first. Wedge opposite side shim between bearing cup and spacer. Install shim so chamfered side is against spacer. It may be necessary to partially remove differential case to install right side shim. If necessary, carefully tap shim into place with a soft-faced hammer. Tighten bearing cap bolts to specifications. See «TORQUE SPECIFICATIONS»(/gmc/jimmy-typhoon/1992-1993/remont/differentials-drive-axles/#drive-axle-75-95) table. Check backlash. See «BACKLASH & FINAL ASSEMBLY»(/gmc/jimmy-typhoon/1992-1993/remont/differentials-drive-axles/#drive-axle-75-95__backlash-final-assembly).

9 1/2" Ring Gear

1. Differential side bearing preload is adjusted by adjusting nut in right differential bearing bore and by adjusting shims in left bearing bore. Bore and bearing cap provide mating threads for preload adjusting nut.
2. Install bearing races to differential bearings. Install differential case into axle housing assembly and temporarily hold in position by hand. Install bearing shims so chamfered side is against spacer.
3. Push differential case away from pinion and install adjusting nut. Tighten right side preload adjusting nut using Spanner Wrench (J-24429 ). Turn pinion to seat differential case bearings.
4. Back off adjusting nut slightly. Install bearing caps and snug tighten bolts. Turn adjusting nut until nut contacts shim. Note nut position and tighten nut 3 additional slots.
5. Tighten bearing cap bolts to specification. Install adjusting nut lock bolt and tighten to specification. Refer to the «TORQUE SPECIFICATIONS»(/gmc/jimmy-typhoon/1992-1993/remont/differentials-drive-axles/#drive-axle-75-95) table. Check backlash adjustment. See «BACKLASH & FINAL ASSEMBLY»(/gmc/jimmy-typhoon/1992-1993/remont/differentials-drive-axles/#drive-axle-75-95__backlash-final-assembly) .

BACKLASH & FINAL ASSEMBLY

1. Rotate pinion and differential case several times to seat bearings. Using a dial indicator mounted to axle housing, check ring gear backlash at 4 different teeth locations around ring gear. Install indicator in line with gear rotation and perpendicular to tooth angle.
2. Pinion flange must be locked in position or held rigid while taking each backlash reading. Four backlash readings should not vary more than.002" (.05 mm).
3. Total backlash reading should be.005-.009" (.13-.23 mm). If backlash is incorrect, adjust side bearing shims as necessary. After backlash adjustment is completed, perform gear tooth contact pattern check. See «GEAR TOOTH CONTACT PATTERNS»(/gmc/jimmy-typhoon/1992-1993/remont/drivelineaxles/#gear-tooth-contact-patterns-general-information) article in the GENERAL INFORMATION section.
4. If pattern is incorrect, adjust pinion or ring gear as required. Install axle shafts, "C" locks, pinion shaft and lock bolt. Install rear housing cover and add gear oil. (Scheme 26) NOTE: DO NOT change total shim pack thickness for each side bearing. If a shim is removed from one side, add same thickness shim to other side.

AXLE ASSEMBLY SPECIFICATIONS

AXLE ASSEMBLY SPECIFICATIONS

TORQUE SPECIFICATIONS

TORQUE SPECIFICATIONS

Scheme 26

See also:
• DRIVE AXLE RATIO IDENTIFICATION
• DRIVE AXLE - EATON LOCKING DIFFERENTIAL TYPE
• TROUBLE SHOOTING - BASIC PROCEDURES
• GEAR TOOTH CONTACT PATTERNS
• MODEL IDENTIFICATION
• PINION FLANGE & OIL SEAL
• SIDE BEARING PRELOAD
• BACKLASH & FINAL ASSEMBLY