Specs, fluids & service · 1973–1991
Chevrolet/GMC Suburban (1973–1991 square body) specs, fluids and service intervals
The numbers you need in the garage, on one page: spec sheet, capacities and service intervals, wheels and tires, and the parts to order. Sourced from owners, specialists and the factory; tags marked confirm in manual haven't been checked against a factory source yet.
Spec sheet
| MODEL YEARS | 1973–1991 |
|---|---|
| 4x4 SERIES | K10 / K20 (GMC K15 / K25) → V10 / V20, V1500 / V2500 (1987–91) |
| WHEELBASE | 129.5 in (3,289 mm) |
| LENGTH / WIDTH | 219.1 in / 79.6 in |
| DOORS | 4 side doors + double rear doors or tailgate |
| SEATING | Up to 9 |
| 4x4 ENGINES | 250 I6 · 307 · 350 · 400 V8 · 6.2 diesel V8 (1982–91) |
| TRANSMISSIONS | 3- and 4-spd manuals · TH350 · TH400 · 700R4 (1981+) · 4L80-E (1991) |
| TRANSFER CASE | NP205 · NP203 full-time (1973–79) · NP208 (1981+) |
| GVW | 5,400–8,200 lb (1973) |
| STOCK TIRES | P215/75R15 (K10) · LT235/85R16 (K20), 1982 |
| TOWING (GCWR) | 11,000 lb K10 · 12,000 lb K20 (1982, gas) |
| WHEEL BOLT PATTERN | 6 x 5.5 in (half-ton 4x4) |
By year
| YEARS | PLATFORM | ENGINE | OUTPUT | NOTES |
|---|---|---|---|---|
| 1973–1974 | K10 / K20 (GMC K15 / K25) | 250 I6 · 307 V8 (1973) · 350 V8 | 350: 175 hp / 275 lb-ft (4-bbl) | New four-door body. NP205 part-time or NP203 full-time. Custom Deluxe and Cheyenne Super trims. |
| 1975–1980 | K10 / K20 | 350 V8 · 400 V8 (K only) | 400: 185 hp / 300 lb-ft | Scottsdale and Silverado trims from 1975. Estate woodgrain package to 1979. Full-time 4WD dropped for 1980. |
| 1981–1986 | K10 / K20 | 350 V8 · 6.2 diesel V8 (from 1982) | 6.2: 130–148 hp | Facelift with rectangular lamps. NP208 with auto-locking hubs. 700R4 four-speed automatic available. |
| 1987–1988 | V10 / V20 (V1500 / V2500) | 5.7 L TBI V8 · 6.2 diesel | TBI 350: 210 hp / 300 lb-ft (10 series) | R/V naming. Throttle-body fuel injection on all gasoline engines. |
| 1989–1991 | V1500 / V2500 | 5.7 L TBI V8 · 6.2 diesel | As above | Flush black grille and new steering wheel (1989). Rear ABS option (1990). 4L80-E for 1991, per Wikipedia. |
| 1973–1991 | C/R 2WD (for comparison) | 454 V8 option | 230 hp | The big block was only a factory option on 2WD Suburbans. |
Fluids, capacities & service intervals
These trucks are 35 to 50 years old, so assume every fluid, hose and bushing is overdue. Identify what you actually have (transfer case, engine, half- or three-quarter-ton), because the service differs. We couldn't verify factory capacities, so confirm them in the GM shop manual.
| ITEM | SPEC / CAPACITY | INTERVAL | NOTES & PARTS |
|---|---|---|---|
| Engine oil & filter | Grade and capacity confirm in manual · the 6.2 diesel takes a diesel-rated oil and more of it | Now, then every 3,000–5,000 mi confirm in manual | Check for leaks at the rear main seal and oil pan.1985 Suburban filters by engine · RockAuto ↗ |
| Ignition (gas) or glow plugs (6.2 diesel) | Plugs, cap, rotor and wires · or glow plugs and controller | Now | Hard cold starts on a diesel usually mean glow plugs or the controller.1989 V10 Suburban ignition and glow plug parts · RockAuto ↗ |
| Coolant, hoses, radiator & fan clutch | Coolant type and capacity confirm in manual | Flush now, then every 2 years | Towing and big tires load the cooling system. On a 6.2, check the harmonic balancer while the front of the engine is accessible (Wikipedia lists balancer-related crank failures).1985 Suburban cooling parts · RockAuto ↗ |
| Automatic transmission fluid & filter | TH350 / TH400 / 700R4 / 4L80-E confirm in manual | Pan drop and filter now | Recall 93V016 added a longer transmission vent hose to 1988–91 trucks after heat pushed fluid out of the vent. Check yours has it.1989 V10 Suburban transmission parts · RockAuto ↗ |
| Transfer case fluid | NP208: Dexron ATF · NP205: 80W-90 gear oil · NP203: CK5 members use 10W-30 motor oil (debated) | Now | Identify the case first. The 203 is long, in four sections and full-time; the 205 is one piece of iron; the 208 is aluminum (ORD, Wikipedia).Remanufactured GM 6-bolt NP205 · Offroad Design ↗ |
| Front & rear differential oil | Gear oil grade confirm in manual | Now, and after deep water | Many trucks have the G80 automatic locking rear differential, which locks itself below about 20 mph when a wheel slips (Wikipedia). Don't mistake its clunk for a failure.10-bolt front axle parts · Offroad Design ↗ |
| Front wheel bearings, spindle seals & hubs | Repack with wheel-bearing grease | Now | On 1981-and-later trucks, check that the automatic hubs engage and release.GM Dana 44 / 10-bolt wheel bearing kit (per side) · Offroad Design ↗Warn internal-style locking hubs · Offroad Design ↗ |
| Brake fluid, lines, rotors & hoses | DOT 3 confirm in manual | Flush now, then every 2 years | Recall 93V119 replaced front rotors on 1988–91 Chevrolets, because road salt could separate the steel hat from the cast outer section. Inspect the rotors on salt-belt trucks.Stainless braided brake lines · Offroad Design ↗1989 V10 Suburban brake parts · RockAuto ↗ |
| Steering box mount, box & linkage | Inspect the frame · check box and linkage for play | Now | Lifted trucks on big tires need the box mount braced (Hagerty, ORD).Bolt-in steering box frame brace, 1973–91 4WD · Offroad Design ↗ |
| Spring & shackle bushings, shocks | Inspect for cracking and sag | Now | Measure ride height at all four corners; Suburbans commonly sag at the rear.Universal 1969–1991 full vehicle bushing kit · Offroad Design ↗ |
| Driveshaft U-joints & slip yokes | Grease the serviceable joints | Every oil change | The long rear shaft and any lift change the driveshaft angles. ORD has a tech page on driveshaft angles.1985 Suburban driveline parts · RockAuto ↗ |
| Fuel filter, pump & tank | Inline filter (TBI) or carburetor filter | Now, then yearly | Recall 06E043 covers certain FRAM G3727 replacement filters with 2005–06 date codes sold for 1987–91 trucks. Check what's fitted.1989 V10 Suburban fuel system parts · RockAuto ↗ |
| Front & rear heat and A/C | Function check · refrigerant type depends on year and any conversion | Now | Hagerty warns that the Suburban-only rear HVAC parts can be hard to fix.1985 Suburban heating and A/C parts · RockAuto ↗ |
| Tailgate glass, rear doors & seals | Operate the glass · water-test the seals | Now | The power glass won't rise unless the tailgate is latched (Wikipedia).73–91 Suburban tailgate parts (search) · Auto Metal Direct ↗ |
Capability
| Towing | 11,000 lb GCWR (K10) · 12,000 lb GCWR (K20) 1982, gasoline 350 with trailering package. The 1973 brochure claims up to 14,000 lb combined for a Series 20 |
|---|---|
| GVW | 5,400–8,200 lb (1973) · 6,100–6,800 lb K10, 8,600 lb K20 (1982) |
| Payload | Up to 3,325 lb 1973 brochure |
| Cargo space | Up to 144 cu ft 1973 brochure |
| Seating | Up to 9 |
| Wheelbase | 129.5 in (3,289 mm) |
| Length | 219.1 in (5,565 mm) |
| Height | 73.8 in (V10) · 76.1 in (V20) |
| Rear door opening | 40 in high × 59.6 in wide 1973 brochure, panel doors |
| Curb weight | 5,837 lb (2,648 kg) Wikipedia infobox figure; varies by series and equipment |
Wheels & tires
| Factory tire | P215/75R15 (K10/V10, 1982 and 1987) · LT235/85R16 (K20/V20, 1982 and 1987) |
|---|---|
| Bolt pattern | 6x139.7 (6x5.5") on half-ton 4x4s |
| Biggest tire · Stock | 31x10.50R15 |
| Biggest tire · 3 in F / 4 in R | 33x12.50R15 |
| Biggest tire · 6 in | 35x12.50 |
Open the Chevrolet/GMC Suburban (1973–1991 square body) in the tire fitment tool →
Common Chevrolet/GMC Suburban (1973–1991 square body) repairs
- Brace or repair the frame at the steering boxDIFFICULTY 3 / 5
- Replace rotten rockers and floor supportsDIFFICULTY 4 / 5
- Convert automatic locking hubs to manual hubsDIFFICULTY 2 / 5
- Repack front wheel bearings and replace spindle sealsDIFFICULTY 3 / 5
- Fix a power tailgate window that won't moveDIFFICULTY 3 / 5
- Rebush the leaf springs and cure the sagDIFFICULTY 3 / 5
- Replace a cracked dash padDIFFICULTY 2 / 5
Always confirm torque figures, fluids and capacities against the factory service manual for your VIN. See the disclaimer; some parts links are affiliate links.