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OEM 3344755 Synchronizer for Eaton FSO4405 Gearbox-PairGears
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| Categories | Gears and Shafts of Eaton Series |
| Trademark/Brand | PairGears Precision Gear Manufacturer |
| Model | PGEA548 |
| OEM No. | 3344755, 2P0311243 |
| Teeth | Z=57/57 |
| Size | OD:159.8 mm H:23.2 mm |
| Weight(Kg) | 1.6469 |
| Process | Grinding Teeth |
| Meterial | 20CrMnTi |
| Heat Treatment | Carburizing |
| Hardness | 58-63HRC |
| Surface Treatment | Shot Peening |
| Update Time | Dec 13,2025 |
Detail Information
PRODUCT DESCRIPTION
Eaton Gearbox FSO4405 Synchronizer 3344755, 2P0311243
The synchronizer OEM No 3344755, 2P0311243 is fit for:
Eaton Gearbox Model: FSO4405.
It is a critical component for maintaining the proper functioning of trucks. It is essential for ensuring the smooth operation of the truck's transmission system.
Pairgears is committed to providing customers with high-precision, efficient transmission, strong durability, low noise, safe and reliable gear products.For quotation or other information, please contact us and we will be happy to help you.
Application
This synchronizer assembly is designed to be compatible with Eaton FSO4405 5-speed transmissions. It works as the 1st/2nd speed synchronizer, allowing the driver to engage the low gears smoothly when starting off or driving at low speed, while protecting the gear teeth from impact.
• Transmission: Eaton FSO4405 gearbox.
• Position: 1st/2nd speed synchronizer assembly on the mainshaft.
• Function: Equalizes the speed of the 1st and 2nd speed gears with the mainshaft, providing smooth, precise shifting in the low gears and helping prevent gear clash.
• Typical use: Medium-duty trucks and distribution vehicles equipped with Eaton FSO4405 transmissions.
Complete Gear & Shaft Coverage for FSO4405
PairGears has developed a complete range of precision gears, shafts and synchronizer components for Eaton FSO4405 5-speed transmissions. Each part is engineered as a drop-in replacement based on the original dimensions and load requirements, helping workshops and fleets restore gearbox performance with confidence.
The exploded view and FSO4405 Parts Summary below show the main components we supply for this transmission. By using the illustration together with the parts list, you can quickly identify the corresponding PairGears part numbers and OEM reference codes required for your overhaul, repair or spare-parts program. If you need a component that is not listed, please contact us with your drawing or sample for further support.
FSO4405 Transmission Exploded View
FSO4405 Parts Summary
No. | PairGears No. | OEM No. | Part Name | Mating Gear | Online Product Page |
1 | PGEA123 | 3361224 | Synchronizer 5A | ||
2 | PGEA547 | 3344765 | Synchronizer 3/4 | ||
3 | PGEA548 | 3344755 | Synchronizer 1/2 | ||
4 | PGEA132 | 3344768 | Synchro Ring 3/4/5 | ||
5 | PGEA129 | 3344778 | Synchro Ring 3/4 | ||
6 | PGEA130 | 3344534 | Synchro Ring 1/2 | ||
7 | PGEA103 | 3344701 | 3rd Speed Gear - Mainshaft | 3341184 | |
8 | PGEA102 | 3344769 | 5th Speed Gear - Mainshaft | 3341107 | |
9 | PGEA108 | 3344777 | Reverse Gear - Mainshaft | 3341182 | |
10 | PGEA120 | 3344260 | Input Shaft | 3341109 | |
11 | PGEA114 | 3344641 | 2nd Speed Gear - Mainshaft | 3341390 | |
12 | PGEA107 | 3344522 | 1st Speed Gear - Mainshaft | 3341390 | |
13 | PGEA117 | 3341164 | Mainshaft | ||
14 | PGEA112 | 3341107 | 5th - Countershaft | 3344769 | |
15 | PGEA116 | 3341109 | Drive Gear - Countershaft | 3344260 | |
16 | PGEA101 | 3341184 | 3rd Gear - Countershaft | 3344701 | |
17 | PGEA118 | 3341390 | Countershaft | 3344522/3344641 |
COMPANY DETAILS
Focus on Precision Gears for 20+ Years
PairGears is a technology-driven precision gear manufacturer focused on the R&D, manufacturing, and sales of transmission gears and shafts for trucks, passenger vehicles, agricultural machinery and construction equipment. We pair application engineering with robust production to deliver reliable gearbox components built for high torque, long duty cycles, and demanding field conditions.
Over the years, we have built a vertically integrated operation with 300+ sets of equipment, including CNC lathes, gear hobbing and shaving machines, gear grinders, and in-house heat-treatment lines. Our production and metrology systems—sourced from Germany, the United States, and Japan—underpin consistent quality and strong development capability in gear design, process optimization, and measurement.
Gear Machining Service
BROACHING
High-throughput broaching of internal/external splines and keyways; consistent profiles for precise shaft–hub fits.
GRINDING
Finish grinding to ISO Grade 4–6; improves finish, cuts noise, boosts load/contact uniformity—ideal for high-speed, high-load.
HOBBING
Flexible hobbing for spur/helical gears; stable indexing with consistent pitch and tooth form for volume runs.
HEAT TREATMENT
Carburizing, induction hardening, and nitriding with controlled case depth for hardness and core toughness.
LASER CUTTING
Rapid laser blanking and feature cutting; clean edges, minimal HAZ—ideal for prototypes and small batches.
SHAPING
Shaping for internal teeth, splines, blind hubs; keeps form/concentricity under constraints—for small batches, complex parts.
SHAVING
Pre-finish shaving refines flank topology, lowering noise and improving accuracy before heat-treat/grinding.
MILLING
CNC milling of blanks and datum faces; precise allowance and concentricity for downstream gear machining.
Precision Gear Customization Process
Step 1 — Requirement Collection
Customers share design requirements for custom precision gears and shafts—drawings, specs, load cases, or samples.
Step 2 — Drawing Design
PairGears runs DFM, optimizes geometry from 2D/3D or samples, then sends transmission gear drawings for confirmation.
Step 3 — Product Quotation
After drawings are confirmed, we provide an accurate quote covering material, heat treatment, tolerances, and delivery for precision gears.
Step 4 — Tooling & Mold Making
Upon price confirmation, we produce tooling/fixtures/molds. Tooling costs are paid upfront and refunded after bulk orders.
Step 5 — First Sample Approval
First-article sample in ~30 days for inspection and functional tests; customer checks fitment and gives feedback until approval.
Step 6 — Mass Production
With the approved sample, PairGears schedules batch manufacturing of precision gears and shafts to meet your demand plan.
Step 7 — Finished-Product Inspection
Inspect hardness, key dimensions, runout, tooth profile/lead, surface roughness to ensure 100% compliance; full reports provided.
Step 8 — Shipping Arrangement
After QC pass and customer confirmation, we book and ship globally for ag machinery, truck, and construction gearbox parts.
COOPERATIVE BRAND
John Deere
Case IH
Valtra
Massey Ferguson
Caterpillar
Eaton
ZF
BYD
EXHIBITION
PairGears At The Exhibition
PairGears is a technology-driven precision gear supplier. At shows in the Americas, Europe, and Asia, we meet OEMs and distributors, listen to needs, and introduce our custom gears and shafts for agriculture, trucks, construction equipment, and EVs.
What You’ll See At Our Booth
Real parts you can hold and compare—spur/helical gears, bevel sets, planetary parts, and gearbox shafts. Our team will provide a detailed introduction to the processing methods, commonly used materials and approximate delivery dates, and will also answer any questions you have.
How We Help On Site
Bring a drawing, gear photo, or rough specs. We’ll discuss feasibility, suggest practical options, and outline next steps for quotation or sampling.
Stay Updated
FAQ
Q: Which truck platforms are supported?
A : We cover ZF, Eaton/Fuller, Mercedes-Benz, Volvo, Scania, IVECO, DAF, Volkswagen, Sinotruk, MAN manual/AMT platforms. Fitment by OEM part number and gearbox model.
Q: What gear/shaft types do you supply for heavy-duty trucks?
A : We supply spur/helical/bevel/worm gears, synchronizers, input/intermediate/output shafts, crown wheel & pinion sets, PTO gears, planetary gear sets, differential gears.
Q: What materials and heat treatments are used for Truck gears?
A : Materials include 20MnCr5, 20CrMnTi, 18CrNiMo7-6, 42CrMo; heat treatments carburizing, induction hardening, nitriding, followed by tempering and grinding/superfinishing for load and wear resistance.
Q: How do you ensure accuracy grades and inspection?
A : We meet ISO 1328 targets: typically Grade 6–8 for shaved gears and Grade 4–6 for ground gears. Reports include profile/lead, runout, over-pins/balls span, spline gauges, with full records.
Q: What are the MOQ and lead times?
A : We support MOQ = 1 pc for prototypes and spares. Typical timing: samples 2–3 weeks, production 3–6 weeks depending on drawings, materials and heat treatment; capacity can be reserved in peak seasons.
Q: How to confirm fitment with our truck/gearbox?
A : Three ways:
(1) search by OEM P/N;
(2) verify by machine/gearbox model + position;
(3) send a sample or drawing (module, teeth, pressure angle, helix, face width, hardness, profile shift, etc.) for reverse-measurement and validation.
Q: Do you cover both early and current production classic models?
A : Yes. We have long provided compatible replacement gears for both early and currently manufactured models, and we continuously update our database.
Q: What Accompanying Quality Inspection/Technical Documents Can You Provide?
A : We can provide documents such as hardness test records, critical dimension inspection reports, material and heat treatment certificates, etc., according to the project, to meet the compliance requirements of truck spare parts channels and OEMs/Tier 1 suppliers.
AFTER-SALES SUPPORT
Scope
Covers typical issues with installation, fitment, noise, and wear for precision gears, agricultural gears, and transmission shafts.
How To Reach Us
Contact our team via form / email / phone. We respond promptly on business days with practical next steps.
What To Include
PO/Part No. (or OEM No.), machine/gearbox model, issue description (when/conditions), and photos or a short video.
Response & Resolution
Initial assessment → actionable advice (install checks, lubrication, replacement options) → if needed, re-inspection or remake/replacement.
Warranty Summary
Follows your contract/PI. Manufacturing-related defects are handled by repair or replacement as agreed. Overload, poor lubrication, or mis-installation are excluded.
On Receipt & Shipping
Please inspect on arrival. For shipping damage or discrepancies, contact support immediately for assistance.
Our Promise
Clear, plain-language guidance and realistic, workable timelines to reduce downtime and communication costs.
PACKAGING
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Join Our Distributors
Are you looking for a partnership with huge market potential and generous profit margins? As our distributor, you will receive comprehensive market support, high-quality product resources, and professional business training. Contact us now to learn more about becoming our distributor and start your journey to success!
- *Name
- Mobile Phone
- *Title
- *Content