--- product_id: 321925241 title: "TranSynd 668 Synthetic Automatic Transmission Fluid, 1 gal" brand: "castrol" price: "€ 196.93" currency: EUR in_stock: true reviews_count: 13 category: "Castrol" url: https://www.desertcart.fi/products/321925241-transynd-668-synthetic-automatic-transmission-fluid-1-gal store_origin: FI region: Finland --- # Superior thermal stability Advanced gear protection Extended anti-shudder & clutch durability TranSynd 668 Synthetic Automatic Transmission Fluid, 1 gal **Brand:** castrol **Price:** € 196.93 **Availability:** ✅ In Stock ## Summary > ⚙️ Shift into the future with Castrol TranSynd 668 – where performance meets precision. ## Quick Answers - **What is this?** TranSynd 668 Synthetic Automatic Transmission Fluid, 1 gal by castrol - **How much does it cost?** € 196.93 with free shipping - **Is it available?** Yes, in stock and ready to ship - **Where can I buy it?** [www.desertcart.fi](https://www.desertcart.fi/products/321925241-transynd-668-synthetic-automatic-transmission-fluid-1-gal) ## Best For - castrol enthusiasts ## Why This Product - Trusted castrol brand quality - Free international shipping included - Worldwide delivery with tracking - 15-day hassle-free returns ## Key Features - • **Clutch Confidence:** Enhanced clutch-friction durability ensures reliable, consistent shifting under pressure. - • **Unrivaled Gear Defense:** Protect your transmission with cutting-edge synthetic formula designed for peak performance. - • **Long-Lasting Smoothness:** Experience extended anti-shudder durability that keeps your drive silky smooth mile after mile. - • **Corrosion & Foam Fighter:** Built-in resistance to corrosion and foaming protects your transmission’s longevity. - • **Universal Fit, Ultimate Convenience:** One synthetic fluid to rule them all—compatible with a wide range of automatic transmissions. ## Overview Castrol TranSynd 668 Synthetic Automatic Transmission Fluid is a premium 1-gallon synthetic fluid engineered to deliver superior gear protection, extended anti-shudder and clutch-friction durability, and excellent resistance to corrosion and foaming. Its advanced thermal and oxidative stability prevents deposits and oil thickening, ensuring smooth, reliable transmission performance across a universal fit range. ## Description Buy Castrol TranSynd 668 Synthetic Automatic Transmission Fluid, 1 gal: Fuel Additives - desertcart.com ✓ FREE DELIVERY possible on eligible purchases Review: Can’t go wrong with this transmission fluid - Best trans fluid for my Duramax with the Allison 1000 Came over night and less cost than the auto stores that don’t even stock it Review: Only fluid to use in any Allison transmission - Started using Tes fluids 8 years ago in my 2005 duramax. Trans developed a shudder and jerking motion going downhill in cruise control. Called Allison tech support. Was told Dex VI wasn't good enough to protect 1000 series trans internals and seals. Changed to Tes 295 and all trans symptoms disappeared. Did forward system flush to get all Dex VI out of the system. 4 gal. Now I'm using 668. 322,000 mi and the trans shifts like new. Can be used in NP and Magna 263 and 261 transfer cases . I do a pan drain every 2 years and canister filter every 12 mo. The cleaner the fluid the cooler it runs. ## Features - Delivers improved gear protection. - Delivers extended anti-shudder durability. - Delivers extended clutch-friction durability. - Excellent corrosion and foaming resistance. - Excellent thermal and oxidative stability that helps to prevent deposits and oil thickening. - Fit type: Universal ## Technical Specifications | Specification | Value | |---------------|-------| | ASIN | B095SZB2DK | | Best Sellers Rank | #5,261 in Automotive ( See Top 100 in Automotive ) #22 in Transmission Fluids | | Brand | Castrol | | Brand Name | Castrol | | Container Type | Bottle | | Customer Reviews | 4.8 out of 5 stars 1,059 Reviews | | Item Form | Liquid | | Liquid Volume | 1 gallons | | Material | Synthetic | | Number of Items | 1 | | Package Information | Bottle | | Part Number | TES 668 | | Recommended Uses For Product | Automotive | | UPC | 079191219164 | | Unit Count | 128 Fluid Ounces | ## Product Details - **Brand:** Castrol - **Liquid Volume:** 1 gallons - **Material:** Synthetic - **Package Information:** Bottle - **Recommended Uses For Product:** Automotive ## Images ![TranSynd 668 Synthetic Automatic Transmission Fluid, 1 gal - Image 1](https://m.media-amazon.com/images/I/71RP2LrvVRL.jpg) ## Available Options This product comes in different **Number Of Items** options. ## Questions & Answers **Q: Can I use this in my 2001 silverado 2500hd with an allison transmission?** A: Yes, I recommend flushing and filter (Both) try to remove as much of the Dino oil as possible. Transcend works wonderfully in my '01 and '05 Chev Allisons **Q: Can this be use with nissan rogue 2017?** A: no **Q: Ok for Genesis 80 2017** A: no **Q: I am trying to find the color of the fluid. Not able to find it on the product description. Any comments?** A: It's red. Just like the older version. ## Customer Reviews ### ⭐⭐⭐⭐⭐ Can’t go wrong with this transmission fluid *by R***F on May 25, 2026* Best trans fluid for my Duramax with the Allison 1000 Came over night and less cost than the auto stores that don’t even stock it ### ⭐⭐⭐⭐⭐ Only fluid to use in any Allison transmission *by M***5 on February 26, 2026* Started using Tes fluids 8 years ago in my 2005 duramax. Trans developed a shudder and jerking motion going downhill in cruise control. Called Allison tech support. Was told Dex VI wasn't good enough to protect 1000 series trans internals and seals. Changed to Tes 295 and all trans symptoms disappeared. Did forward system flush to get all Dex VI out of the system. 4 gal. Now I'm using 668. 322,000 mi and the trans shifts like new. Can be used in NP and Magna 263 and 261 transfer cases . I do a pan drain every 2 years and canister filter every 12 mo. The cleaner the fluid the cooler it runs. ### ⭐⭐⭐⭐⭐ Great for the Allison *by J***N on January 7, 2026* Great fluid. Chevy shifting so much better now. ## Frequently Bought Together - Stone River Products Castrol TranSynd 668 Allison 2021 Updated SPEC 1 GALLON ONLY BY DOXA WORLDWIDE - Allison 29539579 Screw-on Filter with Magnet Filter Kit replacing filter for Allison transmission per OEM Specs, For utility terrain vehicles - ACDelco GM Original Equipment PF2232 Engine Oil Filter --- ## Why Shop on Desertcart? - 🛒 **Trusted by 1.3+ Million Shoppers** — Serving international shoppers since 2016 - 🌍 **Shop Globally** — Access 737+ million products across 21 categories - 💰 **No Hidden Fees** — All customs, duties, and taxes included in the price - 🔄 **15-Day Free Returns** — Hassle-free returns (30 days for PRO members) - 🔒 **Secure Payments** — Trusted payment options with buyer protection - ⭐ **TrustPilot Rated 4.5/5** — Based on 8,000+ happy customer reviews **Shop now:** [https://www.desertcart.fi/products/321925241-transynd-668-synthetic-automatic-transmission-fluid-1-gal](https://www.desertcart.fi/products/321925241-transynd-668-synthetic-automatic-transmission-fluid-1-gal) --- *Product available on Desertcart Finland* *Store origin: FI* *Last updated: 2026-09-07*