(231) 267-5221 5780 Moore Road, Williamsburg, MI   49690
Functional Plastics - Grand Traverse
100% Ontime


Tier 1 and Tier 2

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IATF:16949:2016 Certified

We have served the automotive industry since our founding in 1981, delivering to the exacting standards of global OEMs and Tier 1 suppliers. As the complexity of parts and assemblies has evolved, so too have our engineering and technical capabilities, all in-step with the demands of today’s vehicles and their intricate systems. Automotive customers rely on our rapid prototyping, additive manufacturing, material knowledge and most importantly, our deep experience in converting metal parts to plastic.

GTP’s product portfolio includes a variety of engine, transmission, fluid handling, and other critical use functional plastics. Key assemblies include engine and rocker covers, internal engine parts, oil fill tube caps and assemblies and transmission closeouts.

Recently, we have begun to investigate a multitude of applications for Hybrid and Battery Electric Vehicles, notably in the areas of thermal management, battery containment, lighting, electrical and interior applications – all of which require specialty resins and manufacturing knowledge.

-   Active and Passive Safety

To help satisfy the requirements needed for these safety-critical components, GTP utilizes an extensive APQP Process. We begin with encouraging collaborative engineering with our customers using the latest in design and simulation software to evaluate part and mold design prior to proceeding to production tooling. This includes Mold Flow Analysis to simulate the flow of the plastic material for optimum product quality and dimensional stability.

+   Underhood

GTP is a leading supplier of Engine Covers, Fuel Rail Covers and other underhood plastics to the OEM’s. With a proven track record of producing and supplying cost-effective solutions which blend high-temperature resins, insulating material, fasteners and other value-add components GTP provides underhood plastic injection molded components that offer Class A surfaces for enhanced appearance, are capable of withstanding the high-heat underhood environment and also offer sound dampening from the noise that engine may generate.

Key to our success in this market segment is our material and engineering experts working hand-in-hand with OEM engineers to develop high-quality, high-performing components and assemblies at optimal costs.

+   Air/Fluid/Gas Management

This has been a segment of significant growth for GTP. We draw upon our experience and expertise to focus on parts for internal and external engine applications that transport oil and coolants, utilizing resins designed to resist corrosive fluids and heat which also incorporate proprietary sealing components that meet performance specifications at competitive pricing.

Typical applications for this growing market segment are Oil Fill Caps/Tube Assemblies, Oil Galley Plugs, Quick Connects (Fuel), Air Intake Manifolds, Air Intake Tubes, Filter Housings, Coolant Valves-Housings, Coolant Bypass Tubes, and others.

+   Electrical

From the beginning, GTP has produced and supplied a wide range of injection molded parts for electrical system applications. Our experience in this area includes connectors for larger powertrain modules, Battery Trays/Covers/Boxes, PCM Brackets, complete Fuse Box assemblies or sheathing for wire harnesses, we have the experience and expertise to mold intricate parts required for today’s intricate electrical systems.

+   Structural

GTP has lead a number of metal-to-plastic conversions in the area of structural vehicle components. These components have included various brackets, radiator supports, structural components, substrates, module covers, Housings. In these instances, GTP used our extensive material knowledge and supply base to specify resin formulations that provided the strength required but with less weight and cost.

This afforded GTP to provide solutions to our customers which offered a high strength-to-weight ratio, boosted fuel economy and no corrosion or degradation when chemically exposed or exposed to harsh climates.

Active and Passive Safety Underhood Air/Fluid/Gas Management

Grand Traverse Plastics

Provider of engineered plastic solutions for both production and prototype applications. We offer extensive engineering and component design, material expertise and sourcing.


1734 Crooks Road
  Troy, MI 48084


5780 Moore Road
  Williamsburg, MI   49690