The 1981 Avanti Ii has 55 drivetrain parts with verified fitment on this page — 7 part types and 11 brands, covering the 5.0L 305cid V8 engine. Each part includes a manufacturer part number and application notes.
On the 1981 Avanti Ii, the drivetrain system moves power from transmission to wheels through axles, CV joints, driveshafts, differentials and wheel-end hardware. 43 parts of the 55 listed are Differential Pinion Bearing / Race (21 parts), Differential Carrier Bearing / Race (12 parts) and Universal Joint (10 parts). The other 4 part types cover the remaining 12 parts.
The 1981 Avanti Ii came with a single engine, the 5.0L 305cid V8, and every part is verified against it.
11 brands supply drivetrain parts for the 1981 Avanti Ii, led by WJB / INMOTION PARTS (13 parts), BCA (8 parts) and TIMKEN (7 parts), plus 8 more brands. Quality grades include Standard Replacement, Economy and Heavy Duty.
A "Popular" badge means the source catalog flagged the part as frequently chosen for the 1981 Avanti Ii. 12 parts have it, including NATIONAL 25523 (Differential Carrier Bearing / Race) and NATIONAL 02872 (Differential Pinion Bearing / Race). Each part number opens a page with every vehicle that part fits.
Differential Carrier Bearing / Race
Economy
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| WJB / INMOTION PARTS | WT25523 | 🇺🇸 US 🇨🇦 CA | Race | View on Amazon |
| WJB / INMOTION PARTS | WT25577 | 🇺🇸 US 🇨🇦 CA | Rearwith 8.5 IN Ring Gear | View on Amazon |
Standard Replacement
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| NATIONAL Popular | 25523 | 🇺🇸 US 🇨🇦 CA | Race | View on Amazon |
| TIMKEN Popular | 25523 | 🇺🇸 US 🇨🇦 CA | Race | View on Amazon |
| TIMKEN Popular | 25577 | 🇺🇸 US 🇨🇦 CA | Rear | View on Amazon |
| BCA | NB25523 | 🇺🇸 US 🇨🇦 CA | Race | View on Amazon |
| BCA | NB25577 | 🇺🇸 US 🇨🇦 CA | Rearwith Spicer 44 Axle(S) | View on Amazon |
| NATIONAL | 25577 | 🇺🇸 US 🇨🇦 CA | Rearwith 8.5 IN Ring Gear | View on Amazon |
| SCHAEFFLER | 25523 | 🇺🇸 US 🇨🇦 CA | Race | View on Amazon |
| SCHAEFFLER | K25577 | 🇺🇸 US 🇨🇦 CA | Rear25.4 mm Width | View on Amazon |
| SKF | BR25523 | 🇺🇸 US 🇨🇦 CA | Race | View on Amazon |
| SKF | BR25577 | 🇺🇸 US 🇨🇦 CA | with 3.2650 In. Outside Diameter Bearing(S)3.2650" Width | View on Amazon |
This table covers the bearings and races that support the differential carrier.
12 Differential Carrier Bearing / Race parts are listed for the 1981 Avanti Ii, from WJB / INMOTION PARTS, NATIONAL, TIMKEN and 3 other brands. NATIONAL 25523 carries the "Popular" badge.
In the Economy grade, WJB / INMOTION PARTS supplies 2 parts: the catalog's value-priced group. A representative part number is WJB / INMOTION PARTS WT25523.
The Standard Replacement section lists 10 options from NATIONAL, TIMKEN, BCA and 2 other brands — built to original-equipment specification. NATIONAL 25523 is listed in this group.
Differential Cover Gasket
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| FEL-PRO | RDS6629 | 🇺🇸 US 🇨🇦 CA | Rearwith Spicer 44 Axle(S) | View on Amazon |
| VICTOR REINZ | 711481100 | 🇺🇸 US 🇨🇦 CA | Rearwith Dana 44 Axle(S) | View on Amazon |
This table covers the gaskets that seal the Differential Cover. Typical signs include seepage at the joint, a burnt-oil smell, or a leak that appears only after a long drive. Clean both flanges and torque in the sequence the notes or the manual call for.
2 Differential Cover Gasket parts are listed for the 1981 Avanti Ii, from FEL-PRO and VICTOR REINZ.
Part numbers include FEL-PRO RDS6629 and VICTOR REINZ 711481100.
Differential Pinion Bearing / Race
Economy
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| WJB / INMOTION PARTS | WT02820 | 🇺🇸 US 🇨🇦 CA | Race | View on Amazon |
| WJB / INMOTION PARTS | WT31520 | 🇺🇸 US 🇨🇦 CA | Race | View on Amazon |
| WJB / INMOTION PARTS | WT02872 | 🇺🇸 US 🇨🇦 CA | Rear Outerwith 8.5 IN Ring Gear | View on Amazon |
| WJB / INMOTION PARTS | WT31594 | 🇺🇸 US 🇨🇦 CA | Rear Innerwith 8.5 IN Ring Gear | View on Amazon |
Standard Replacement
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| NATIONAL Popular | 02872 | 🇺🇸 US 🇨🇦 CA | Rear Outerwith 8.5 IN Ring Gear | View on Amazon |
| TIMKEN Popular | 02820 | 🇺🇸 US 🇨🇦 CA | Race | View on Amazon |
| TIMKEN Popular | 31520 | 🇺🇸 US 🇨🇦 CA | Race | View on Amazon |
| TIMKEN Popular | 02872 | 🇺🇸 US 🇨🇦 CA | Rear Outer | View on Amazon |
| TIMKEN Popular | 31594 | 🇺🇸 US 🇨🇦 CA | Rear Inner | View on Amazon |
| BCA | NB02820 | 🇺🇸 US 🇨🇦 CA | Race | View on Amazon |
| BCA | NB31520 | 🇺🇸 US 🇨🇦 CA | Race | View on Amazon |
| BCA | NB02872 | 🇺🇸 US 🇨🇦 CA | Rear Outerwith Spicer 44 Axle(S) | View on Amazon |
| BCA | NB31594 | 🇺🇸 US 🇨🇦 CA | Rear Innerwith Spicer 44 Axle(S) | View on Amazon |
| NATIONAL | 02820 | 🇺🇸 US 🇨🇦 CA | Race | View on Amazon |
| NATIONAL | 31594 | 🇺🇸 US 🇨🇦 CA | Rear Innerwith 8.5 IN Ring Gear | View on Amazon |
| SCHAEFFLER | K2872 | 🇺🇸 US 🇨🇦 CA | Rear Outer22.225 mm Width | View on Amazon |
| SCHAEFFLER | 2820 | 🇺🇸 US 🇨🇦 CA | Race | View on Amazon |
| SCHAEFFLER | 31520 | 🇺🇸 US 🇨🇦 CA | Race | View on Amazon |
| SKF | BR02820 | 🇺🇸 US 🇨🇦 CA | Race | View on Amazon |
| SKF | BR31520 | 🇺🇸 US 🇨🇦 CA | Race | View on Amazon |
| SKF | BR31594 | 🇺🇸 US 🇨🇦 CA | with 1.3750 In. Bearing Inside Diameter | View on Amazon |
This table covers the bearings and races on the differential pinion.
21 Differential Pinion Bearing / Race parts for the 1981 Avanti Ii come from 6 brands — WJB / INMOTION PARTS, TIMKEN, BCA and 3 other brands. The "Popular" part is NATIONAL 02872.
The Economy section: 4 options from WJB / INMOTION PARTS. WJB / INMOTION PARTS WT02820 is listed in this group.
Standard Replacement: 17 parts, from TIMKEN, BCA, NATIONAL and 2 other brands. A representative part number is NATIONAL 02872.
Differential Pinion Repair Sleeve
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| SCHAEFFLER | SR3481 | 🇺🇸 US 🇨🇦 CA | Rear14.3 mm Width | View on Amazon |
| WJB / INMOTION PARTS | WS99155 | 🇺🇸 US 🇨🇦 CA | Rear Outerwith 8.5 IN Ring Gear | View on Amazon |
This table covers the wear sleeves used to restore a grooved pinion seal surface.
2 Differential Pinion Repair Sleeve parts are listed for the 1981 Avanti Ii, from SCHAEFFLER and WJB / INMOTION PARTS.
This group includes SCHAEFFLER SR3481 and WJB / INMOTION PARTS WS99155.
Differential Pinion Seal
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| SKF Popular | 15788 | 🇺🇸 US 🇨🇦 CA | Rear | View on Amazon |
| WJB / INMOTION PARTS Popular | WS5778 | 🇺🇸 US 🇨🇦 CA | Nitrile | View on Amazon |
| BCA | NS5778 | 🇺🇸 US 🇨🇦 CA | Nitrile | View on Amazon |
| BCA | NS5778V | 🇺🇸 US 🇨🇦 CA | Viton | View on Amazon |
| SCHAEFFLER | SS2633 | 🇺🇸 US 🇨🇦 CA | Rear16.891 mm Width | View on Amazon |
| TIMKEN | 5778 | 🇺🇸 US 🇨🇦 CA | Rear | View on Amazon |
This table covers the seals at the differential pinion yoke. Typical signs include a wet housing, a drip after sitting, or fluid flung off a rotating shaft. Fix the surface the seal rides on. A new seal on a grooved shaft will leak again.
6 Differential Pinion Seal parts are listed for the 1981 Avanti Ii, from BCA, SKF, WJB / INMOTION PARTS and 2 other brands. SKF 15788 carries the "Popular" badge.
This group includes SKF 15788, WJB / INMOTION PARTS WS5778 and BCA NS5778 and the remaining parts above.
Universal Joint
Economy
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| WJB / INMOTION PARTS | UJT269 | 🇺🇸 US 🇨🇦 CA | Grade Type: Performance-Non-Greaseable | View on Amazon |
| WJB / INMOTION PARTS | UJT369 | 🇺🇸 US 🇨🇦 CA | Grade Type: STD-Greaseable | View on Amazon |
| WJB / INMOTION PARTS | UJT280 | 🇺🇸 US 🇨🇦 CA | Grade Type: Performance-Bearing Greaseable | View on Amazon |
Heavy Duty
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| MOOG Popular | 269 | 🇺🇸 US 🇨🇦 CA | Super StrengthNon-Greasable | View on Amazon |
| ACDELCO | 45U0111 | 🇺🇸 US 🇨🇦 CA | Greasable Super StrengthIncludes Flush Type Lube Fitting | View on Amazon |
| GMB | 2150153 | 🇺🇸 US 🇨🇦 CA | PerformanceGreasable | View on Amazon |
| MOOG | 280 | 🇺🇸 US 🇨🇦 CA | Super StrengthGreasable | View on Amazon |
Standard Replacement
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| MOOG Popular | 369 | 🇺🇸 US 🇨🇦 CA | Greasable | View on Amazon |
| ACDELCO | 45U0107 | 🇺🇸 US 🇨🇦 CA | GoldGreasable | View on Amazon |
| GMB | 2100153 | 🇺🇸 US 🇨🇦 CA | GreasableGrease Fitting in Cross | View on Amazon |
This table covers the U-joints in the driveshaft.
10 Universal Joint parts are listed for the 1981 Avanti Ii, from WJB / INMOTION PARTS, MOOG, ACDELCO and 1 other brand. MOOG 269 carries the "Popular" badge.
Economy: 3 parts, from WJB / INMOTION PARTS. A representative part number is WJB / INMOTION PARTS UJT269.
The Heavy Duty section lists 4 options from MOOG, ACDELCO and GMB — rated for severe service. MOOG 269 is listed in this group.
The Standard Replacement section: 3 options from MOOG, ACDELCO and GMB. MOOG 369 is listed in this group.
Universal Joint Strap Kit
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| WJB / INMOTION PARTS | UJT43710 | 🇺🇸 US 🇨🇦 CA | Rear Shaft All Joints1/4-28 Bolts | View on Amazon |
| WJB / INMOTION PARTS | UJT36010 | 🇺🇸 US 🇨🇦 CA | Rear Shaft All Joints5/16-24 Bolts | View on Amazon |
This table covers the Universal Joint Strap kits.
WJB / INMOTION PARTS supplies both parts for the 1981 Avanti Ii.
Listed part numbers: WJB / INMOTION PARTS UJT43710 and WJB / INMOTION PARTS UJT36010.
Buying Drivetrain Parts for a 1981 Avanti Ii
On this vehicle, the drivetrain system moves power from transmission to wheels through axles, CV joints, driveshafts, differentials and wheel-end hardware.
- Confirm you have the 5.0L 305cid V8 engine — every part on this page is matched to it.
- Read the notes on each row for position, trim and spec qualifiers before you order.
- Where labor overlaps, replace the differential or transfer-case fluid with any axle or seal job while everything is already open.
- Cross-reference the manufacturer part number against your old part or a service-manual listing.
Start with the largest groups on this page: Differential Pinion Bearing / Race and Differential Carrier Bearing / Race .
Frequently Asked Questions
How many drivetrain parts fit the 1981 Avanti Ii?
Our catalog currently lists 55 drivetrain parts for the 1981 Avanti Ii across 7 subcategories and 11 brands, covering the 5.0L 305cid V8 engine. Each part is matched to the engine(s) it fits.
What are the signs of drivetrain problems on a 1981 Avanti Ii?
Common symptoms include clicking in tight turns, a clunk when shifting between drive and reverse, vibration that builds with speed, or gear oil on the inside of a wheel. If you notice any of these, identify the affected subcategory above and cross-reference the part numbers listed.
What should I replace at the same time?
Where labor overlaps, replace the differential or transfer-case fluid with any axle or seal job while everything is already open.
What do the market flags (US, CA, MX) on each part mean?
They show the market for which the manufacturer published application data for that part — where the vehicle was first sold, not where the part was made. If your 1981 Avanti Ii was originally sold in the US, the safest choice is a part marked for the US market.
How do I make sure a part fits my 1981 Avanti Ii?
Every part on this page is matched to the 5.0L 305cid V8 engine. Then a torn CV boot caught early is a cheap boot kit; caught late it is a whole axle — inspect before deciding which to buy. The notes column carries position and trim qualifiers where they apply.
Other Parts for the 1981 Avanti Ii
Drivetrain Parts for Other Avanti Ii Years
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