---
product_id: 321925241
title: "Stone River Products Castrol TranSynd 668 Allison 2021 Updated SPEC 1 GALLON ONLY BY DOXA WORLDWIDE"
brand: "castrol"
price: "NT$5080"
currency: TWD
in_stock: true
reviews_count: 13
category: "Castrol"
url: https://www.desertcart.tw/products/321925241-stone-river-products-castrol-transynd-668-allison-2021-updated-spec
store_origin: TW
region: Taiwan
---

# Thermal & oxidative stability Superior gear protection Extended clutch & anti-shudder durability Stone River Products Castrol TranSynd 668 Allison 2021 Updated SPEC 1 GALLON ONLY BY DOXA WORLDWIDE

**Brand:** castrol
**Price:** NT$5080
**Availability:** ✅ In Stock

## Summary

> 🛠️ Elevate your transmission game with Castrol TranSynd 668 — where durability meets precision.

## Quick Answers

- **What is this?** Stone River Products Castrol TranSynd 668 Allison 2021 Updated SPEC 1 GALLON ONLY BY DOXA WORLDWIDE by castrol
- **How much does it cost?** NT$5080 with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.tw](https://www.desertcart.tw/products/321925241-stone-river-products-castrol-transynd-668-allison-2021-updated-spec)

## 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

- • **Thermal Mastery:** Outstanding thermal and oxidative stability prevents oil thickening and deposit buildup, ensuring consistent fluidity in extreme conditions.
- • **Next-Level Durability:** Extended anti-shudder and clutch-friction resistance means fewer maintenance worries and peak performance under pressure.
- • **Unmatched Gear Defense:** Engineered to deliver top-tier protection against wear and tear, keeping your transmission running smoother, longer.
- • **Corrosion & Foam Fighter:** Advanced formula resists corrosion and foaming, safeguarding your transmission’s internal components for lasting reliability.
- • **Universal Fit, Premium Synthetic:** Versatile compatibility with Allison, GM 4L80, 6L90, and more — the synthetic upgrade your heavy-duty vehicle deserves.

## Overview

Castrol TranSynd 668 Allison 2021 Updated SPEC is a premium synthetic transmission fluid designed for heavy-duty trucks and GM transmissions. It offers superior gear protection, extended clutch and anti-shudder durability, excellent corrosion and foam resistance, and outstanding thermal and oxidative stability. Compatible with a wide range of vehicles, this 1-gallon bottle delivers reliable, long-lasting performance trusted by professionals.

## Description

desertcart.com: Stone River Products Castrol TranSynd 668 Allison 2021 Updated SPEC 1 GALLON ONLY BY DOXA WORLDWIDE : Everything Else

Review: Great Transmission Fluid - TranSynd 668 is one of the best transmission fluids available on the market currently. Developed specifically to meet rigorous Allison specifications for heavy-duty working trucks. Also works in GM transmissions like 4L80 and 6L90 and has better performance than standard ACDelco or GM Dexron VI or III fluids. OK to mix with Dex until the next fluid change. TranSynd is considered a more versatile premium synthetic option that meets a wider range of specifications and has a higher shear resistance. It can withstand more shearing forces without breaking down, making it a better choice for applications requiring extreme durability. Been running it in all of my GM and Allison transmissions for many years. Recommended.
Review: Great quality you can trust - This is the only transmission fluid I will use on my truck period !!

## 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 | #5,262 in Automotive ( See Top 100 in Automotive ) #20 in Transmission Fluids |
| Brand | Castrol |
| Customer Reviews | 4.9 4.9 out of 5 stars (943) |
| Date First Available | May 25, 2021 |
| Item Form | Liquid |
| Item Weight | 7.5 pounds |
| Liquid Volume | 1 Gallons |
| Manufacturer Part Number | TES 668 |
| Material | Synthetic |
| Number of Items | 1 |
| Package Dimensions | 10.83 x 8.15 x 4.37 inches |
| Package Information | Bottle |
| Recommended Uses For Product | Automotive |
| UPC | 079191219164 |
| Unit Count | 128.0 Fluid Ounces |

## Product Details

- **Brand:** Castrol
- **Item Weight:** 3.41 Kilograms
- **Liquid Volume:** 1 Gallons
- **Material:** Synthetic
- **Package Information:** Bottle

## Images

![Stone River Products Castrol TranSynd 668 Allison 2021 Updated SPEC 1 GALLON ONLY BY DOXA WORLDWIDE - Image 1](https://m.media-amazon.com/images/I/71RP2LrvVRL.jpg)

## 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

### ⭐⭐⭐⭐⭐ Great Transmission Fluid
*by B***L on January 20, 2025*

TranSynd 668 is one of the best transmission fluids available on the market currently. Developed specifically to meet rigorous Allison specifications for heavy-duty working trucks. Also works in GM transmissions like 4L80 and 6L90 and has better performance than standard ACDelco or GM Dexron VI or III fluids. OK to mix with Dex until the next fluid change. TranSynd is considered a more versatile premium synthetic option that meets a wider range of specifications and has a higher shear resistance. It can withstand more shearing forces without breaking down, making it a better choice for applications requiring extreme durability. Been running it in all of my GM and Allison transmissions for many years. Recommended.

### ⭐⭐⭐⭐⭐ Great quality you can trust
*by C***N on December 15, 2025*

This is the only transmission fluid I will use on my truck period !!

### ⭐⭐⭐⭐⭐ great sale
*by A***S on October 19, 2025*

good price for the gallon

## 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

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**Shop now:** [https://www.desertcart.tw/products/321925241-stone-river-products-castrol-transynd-668-allison-2021-updated-spec](https://www.desertcart.tw/products/321925241-stone-river-products-castrol-transynd-668-allison-2021-updated-spec)

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*Product available on Desertcart Taiwan*
*Store origin: TW*
*Last updated: 2026-02-01*