{"product_id":"motorbymotor-universal-window-crank-shaft-extension-for-gm-16-spline-shafts-5-8-11-16-length-increase-c-clip-compatible","title":"MotorbyMotor Universal Window Crank Shaft Extension for GM 16-Spline Shafts — 5\/8\"–11\/16\" Length Increase, C-Clip Compatible","description":"\u003cstrong\u003eMotorbyMotor Universal Window Crank Shaft Extension lengthens a splined window or door latch shaft by 5\/8\"–11\/16\" to restore handle reach on classic GM and many other vehicles.\u003c\/strong\u003e\n\n\u003cp\u003eIf your original window crank or door latch handle sits too close to the door panel after restoration or a new regulator was installed, this compact spline extension gives you the extra length needed without replacing the entire shaft. Designed around the common GM-style splined shafts, it provides a straightforward, reversible solution for older American cars and a surprisingly wide range of domestic and import vehicles.\u003c\/p\u003e\n\n\u003ch3\u003eWill this extension work with my car’s splined shaft?\u003c\/h3\u003e\n\u003cp\u003eThe extension is made for splined shafts commonly found on many 1950–1990 General Motors models and several other makes. It mates to shafts around 1\/2\" diameter and uses the standard 16-spline pattern where a C-clip secures the handle. If your shaft measures roughly .41 to .46 inches in diameter and uses a C-clip attachment, compatibility is very likely.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eFits 16-spline shafts with C-clip handle attachment\u003c\/li\u003e\n  \u003cli\u003eDesigned for ~1\/2\" splined shaft diameters (.41–.46\" GM spec)\u003c\/li\u003e\n  \u003cli\u003eCommon on Chevrolet, GMC, Pontiac, Buick, Olds, Cadillac\u003c\/li\u003e\n  \u003cli\u003eOften compatible with various domestic and many import models\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eHow much extra length does the extension add and can I trim it?\u003c\/h3\u003e\n\u003cp\u003eThis specific extension increases the shaft length by roughly 5\/8\" to 11\/16\"—enough to clear thicker door panels, insulation, or aftermarket door cards. It is manufactured to that fixed length to ensure a secure spline engagement and reliable fit; shorter versions are not offered, and trimming is not recommended because it may compromise spline engagement or retention.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eAdds approximately 5\/8\"–11\/16\" of usable shaft length\u003c\/li\u003e\n  \u003cli\u003eFixed length for secure spline engagement\u003c\/li\u003e\n  \u003cli\u003eNot supplied in shorter sizes; cutting can weaken fit\u003c\/li\u003e\n  \u003cli\u003eInstalls without replacing the regulator or handle\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eWhat vehicles does this extension fit and where is it typically used?\u003c\/h3\u003e\n\u003cp\u003eThe part was developed with broad compatibility in mind: most GM cars and trucks from the 1950s through the 1990s, plus many domestic makes and some import vehicles that adopted similar splined shaft designs. Typical applications include window cranks, door latch release shafts, wing vent cranks and door locks where a 16-spline, C-clip style handle attaches.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eDesigned for Chevy, Camaro, Corvette, Buick, Pontiac, Olds, Cadillac and GM trucks\u003c\/li\u003e\n  \u003cli\u003eCompatible with many Jeep, Dodge, Chrysler, Toyota, Honda and other models using similar splines\u003c\/li\u003e\n  \u003cli\u003eUsed on window regulators, door latch shafts, vent cranks and locks\u003c\/li\u003e\n  \u003cli\u003eIdeal for restorations and repairs where handle clearance is insufficient\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003eWho is this for: This extension is aimed at classic-car enthusiasts, restorers, mechanics and DIYers who need a simple, reversible way to gain a small but crucial amount of shaft length so handles clear panels or aftermarket materials. It’s especially useful when reassembling older GM vehicles or adapting a regulator and handle setup that leaves the crank too recessed. The product is a low-cost, low-effort alternative to replacing shafts or regulators, and it keeps the original handle attachment method intact for an authentic look and feel.\u003c\/p\u003e\n\u003csection class=\"product-faq-snippet\"\u003e\u003ch3\u003eFAQ\u003c\/h3\u003e\n\u003cdiv class=\"faq-item\"\u003e\n\u003cp class=\"faq-q\"\u003eQ: Does this extension fit 16-spline GM window shafts?\u003c\/p\u003e\n\u003cp class=\"faq-a\"\u003eA: Yes. It’s made for 16-spline shafts and C-clip handle attachment common on many GM models from 1950–1990.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"faq-item\"\u003e\n\u003cp class=\"faq-q\"\u003eQ: How much length does the extension add?\u003c\/p\u003e\n\u003cp class=\"faq-a\"\u003eA: The extension adds approximately 5\/8\" to 11\/16\" of shaft length; shorter sizes are not available.\u003c\/p\u003e\n\u003c\/div\u003e\u003c\/section\u003e","brand":"MotorbyMotor","offers":[{"title":"Default Title","offer_id":48085884895390,"sku":"B08K8GTR5B","price":45.42,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0781\/2041\/9486\/files\/motorbymotor-extension-front-view.jpg?v=1785879424","url":"https:\/\/northtrailauto.ca\/products\/motorbymotor-universal-window-crank-shaft-extension-for-gm-16-spline-shafts-5-8-11-16-length-increase-c-clip-compatible","provider":"North Trail Auto","version":"1.0","type":"link"}