Transmission Speedometer Port Plug for GM TH400

Name: Transmission Speedometer Port Plug for GM TH400
Brand: B&M
SKU: 130-20301
Price: 44.96 USD
Availability: InStock

^$44⁹⁶$49.95You Save$4.99

3 left in stock

Ships on Sep 08, 2026

Lowest Price Guarantee

Transmission Speedometer Port Plug

Fits GM TH400 Transmission

Billet Aluminum with Engraved B&M Logo

Mil-Spec Black Anodized Finish

Sold Individually

B&M 20310 Features:

Includes (2) Stainless Steel Mounting Bolts, (1) O-Ring, and (1) Washer
Protects your Transmission from Contaminants During use or Storage
Perfect for Electronic Speedometer Conversions
Replaceable O-Ring Seal for Leak Prevention and Maintenance

Note:

Does NOT fit B.O.P (Buick, Oldsmobile & Pontiac) TH-400 transmissions.

Billet Aluminum Speedometer Plugs

When upgrading to an electronic speedometer, B&M billet aluminum Transmission Speedometer Port Plugs prevent contaminants from entering your transmission by blocking the mechanical speedometer gear port. These durable block-off port plugs are available to fit various transmission styles.

Part TypePlug Fitting

Product LineB&M Transmission Speedometer Port Plug

BrandB&M

Package Height1.0

Package Width5.0

Package Length7.0

Weight0.3 PG

Part CategoryPerformance Parts

QuantitySold individually

MaterialBillet Aluminum

Part FitmentSemi Universal

Vendor Part Number20301