Cummins 4B, 6B, ISB Used Machine-Split Connecting Rod | Replaces 3901566, J942581

Overview

We stand behind every part we sell — new, rebuilt, or used. While RF Engine is not the manufacturer of any product we sell, we are committed to ensuring that each part is accurately represented, inspected where applicable, and delivered in the condition described at the time of sale.

New Parts

All new parts are warranted by the original manufacturer only and are subject to that manufacturer's specific terms and conditions. RF Engine and its subsidiaries do not offer any additional warranty or guarantee of any type, express or implied, on new products. Due to the vast number of manufacturers we work with, no specific warranty details can be outlined here. Please contact us for warranty information pertaining to your specific product.

Rebuilt, Remanufactured & Reconditioned Parts

Rebuilt, remanufactured, and reconditioned parts are used components that have been machined, reassembled, or otherwise restored toward original specifications by a third-party machine shop — not by RF Engine. These parts carry an inspection-only warranty unless otherwise expressly stated in writing by RF Engine at the time of sale. All products must be inspected before installation. By installing the product, the customer is expressly accepting, completely and without reserve, the product and all liability from the point of receipt forward.

Used Parts

Used parts are sold strictly on a representation basis. RF Engine attests that used parts are accurately described and within usable, serviceable condition at the time of sale. No warranty of performance, longevity, or fitness for a particular use is expressed or implied. Used parts are not refurbished, remanufactured, or restored to like-new condition and may exhibit signs of wear, surface rust, blemishes, old gaskets, residue, or other cosmetic imperfections. Further cleaning or machining prior to installation may be required.

No original equipment manufacturer warranties used parts to secondary purchasers, and RF Engine does not extend any warranty beyond accurate representation of condition.

First-Party Purchaser Only

All warranties, representations, and assurances of quality or fitment extended by RF Engine apply exclusively to the original, direct purchaser. These do not transfer to any third party, whether through resale, gifting, or use of the part in a third-party repair or service. RF Engine assumes no obligation or liability to anyone other than the original buyer.

Claims

All claims must be submitted to RF Engine in writing, immediately following any issue and before performing any disassembly or repairs of any type. Unauthorized disassembly, repair, or a delay in claim notification will void any applicable warranty. RF Engine reserves the right to inspect all products involved in any warranty claim. All products being returned for inspection must be sent freight pre-paid.

At no time will any reimbursement exceed the original purchase price of the product in question. Freight charges incurred by the customer will not be refunded under any circumstances. Where a manufacturer's warranty applies, RF Engine will assist the buyer through the claim process; however, the final determination of any warranty claim is made by the manufacturer, not by RF Engine.

Limitation of Liability

RF Engine and its subsidiaries offer no warranty of any kind, either express or implied, with regard to the merchantability or fitness for a particular use of any product sold. RF Engine acts only as a broker with regard to any machine work or outside labor. Any warranty or claim against machine work or outside labor is to be taken up directly with the individual or organization that performed the work.

In no event shall RF Engine be liable for any incidental, consequential, or special damages, including but not limited to engine damage, equipment downtime, labor costs, lost revenue, or any other costs arising from the use or inability to use any product sold by RF Engine, regardless of whether RF Engine has been advised of the possibility of such damages.

Installation & Responsibility

We strongly recommend that all parts be inspected prior to installation and that installation be performed by a qualified heavy-duty diesel mechanic. By installing any product purchased from RF Engine, the customer expressly accepts the product and assumes all liability from the point of installation forward.

Questions?

If you have questions about a part's condition, warranty coverage, or our claims process, feel free to contact us. We're here to help.

Last Updated: June 22, 2025