Best Transmission Fluid Additives of 2025

"I was skeptical at first, but after using the Lubegard 19610 Dr. Tranny Instant Shudder Fixx, I felt like I had a new transmission. My car drives smoothly now, and the shuddering has disappeared. I can't believe something so small made such a big difference!"

"I didn't expect much from the product, but I was pleasantly surprised. Right after adding it to our 2020 Traverse, I noticed the shuttering was gone almost immediately. My wife even remarked on how smooth the car felt, which is impressive given she usually doesn't notice such changes!"

"I am so happy! After adding 5 ounces of Shift Restore to my F1 transmission, I noticed smooth shifts within 30 miles. The grinding between shifts is completely gone. It's like my car is brand new! I was initially hesitant but contacted the manufacturer, and they reassured me that it wouldn't harm my transmission. The previous owner sold me a lemon, but this product freed up my rusty clutch plates and got everything working smoothly again."

"At my age, I've tried many additives, but this product is remarkable. The improvement was noticeable just a few miles after adding it to my transmission. If it can enhance my old transmission this much, I might joke about drinking some myself!"

"I added just 200ml to my transmission and it resolved the issue where my auto transmission was struggling to shift from 1st to 2nd. I’m impressed with how effective it was!"

"I recently changed the transmission fluid in my Honda CR-V using the Honda FBA_08200-9008 Automatic Transmission Fluid. The fluid poured easily from the well-designed quart bottles. After the change, I felt an immediate improvement in shifting performance—the transmission was much smoother and more responsive. This fluid provides excellent lubrication and protection, preventing wear and ensuring the longevity of my transmission. The 4-quart pack is perfect for DIY maintenance. Overall, I highly recommend this product for anyone wanting to keep their Honda running smoothly!"

"I had been ignoring the signs of my 2003 Honda Odyssey having transmission issues. After experiencing shuddering and grinding sounds, I finally bought this Honda-spec transmission fluid and changed it myself. The process was simple, and now, after the fluid change, my van runs smoothly with no shuddering! I’ve done multiple changes since, and the performance remains like new. I genuinely believe this fluid has saved my old transmission!"

"This Honda ATF is essential; it's simply the only fluid to use for my Honda transmission. I ordered it and received it earlier than expected. After using it, the chattering in my 2012 Honda Civic disappeared completely, and shifting is smoother than ever. I’ll definitely keep an eye on it and update if anything changes."

"I added this product to my 2006 Civic Hybrid with 180K miles, and it fixed the ruddling and sluggish transmission. It's been 3 months, and it’s still working beautifully. I’m amazed at the difference—magical product!"

"I own a 2006 Mitsubishi Lancer. After facing reverse and drive slipping issues, I used this product, and the reverse slipping was instantly fixed. I even spilled some, but it still reduced the noise when shifting gears. The effect was nearly immediate for me!"

"I used this product in my 06 Volvo XC90 before replacing the valve body. Initially, I noticed a slight increase in shifting issues, but after some time, it improved about 10%. I also tried Lucas, which helped more, but this product does have its merits for extending transmission life."

"I own a busy auto repair shop, and I've found this product works as stated. It has resolved many transmission shift issues when added to the transmission fluid. Just a note: not for CVT transmissions."

"I have used this product in my Honda vehicles. After noticing a judder at 35-40 mph, I was hesitant to try it, but it worked incredibly well. I added it without changing the fluid first, and the judder disappeared. Now, it's my go-to solution for five vehicles!"

"I paid $1200 for a torque converter replacement on my 2013 Ford Edge. Instead, I decided to try this product, and after putting in two tubes, the shudder was gone in about 40-60 miles. I couldn't believe how effective it was!"

"I was initially skeptical about this product, but after using it in my 2005 Mazda 3, which had issues with 4th gear slipping, I drove for exactly 140 miles, and then it started performing normally again. I'm truly impressed!"

"I had a transmission issue with my F150 and decided to give this a shot. After changing the oil and adding this product, the difference was astounding! The shifting became smooth, the noise disappeared, and I regained the power I thought I lost."

"At first, I didn't believe in additives, but after trying this one in my Jeep with the 722.6 transmission, I was amazed. After about 500 kilometers, the rough shifting disappeared completely. For the price, it’s definitely worth trying if you're experiencing similar issues."

"I purchased this product to extend the life of my CVT fluid until I could afford a change. It made my transmission operate more quietly and improved performance significantly. I was initially worried about my 2009 Murano's fragile CVT, but this was a perfect temporary fix. I didn’t add another bottle with the new fluid as it seemed unnecessary."

"After struggling with significant hesitation in my 9-year-old Murano, I decided to try this product on my mechanic's suggestion. I noticed a remarkable improvement in just 30 miles. The engine starts better, runs smoothly, and the hesitation is almost gone. I’m impressed enough to have accidentally ordered two bottles! Not only that, but my fuel efficiency has increased from around 15 mpg to 20 mpg!"

"For two weeks, I've used this product in my 2010 Nissan Maxima. It has noticeably improved my throttle response and reduced the transmission shudder I was experiencing. Although I've still felt a slight shudder occasionally, overall, I'm happy with this product and optimistic about prolonging my transmission's life."

"After someone hit my car, I noticed a terrible shifting issue. I tried Prolong, and after adding it, my transmission felt significantly better. Now there's no notching, and it shifts smoothly into all gears!"

"I was experiencing hard shifting and thought my transmission was damaged. After changing the fluid and adding Prolong, it started shifting normally again. It's been running great for months!"

"With my 2010 Hyundai Accent, I was skeptical but decided to try Prolong. I can't believe how smooth the shifts are now, even when the engine is cold. I feel confident I can keep this car for another 75,000 miles!"

"I found Bar's concentrate transmission stop leak to be very effective on my pneumatic BB and pellet guns. Just two or three drops on the pump seal made a noticeable difference on the chronograph, just like Tom Gaylord mentioned."

"I used this product for my 73 Buick with a significant leak at the main seal. I was skeptical, but after using twice the recommended amount, it actually worked! I'm amazed at how well it performed!"

"I applied this stop leak to my manual transmission and within just two hours, the leak was completely gone. By the time I drove the recommended mileage, there was no sign of the leak. This is a great price for such effective results!"

"I used this product in my 2006 Murano, which had a minor transmission seal leak. Surprisingly, after monitoring the leak and adding the product gradually, I noticed a slowdown in the leak. While it didn't completely eliminate the issue, it helped and caused no negative effects on my transmission."

"I have a 2010 Nissan Rogue with a CVT transmission that was failing. To my surprise, after using this product, I felt an immediate difference, and within 50 miles, my transmission was functioning perfectly again. It was a last-ditch effort, but it worked!"

"I applied this product to my CVT transmission, which was overheating and having trouble shifting. After using it, the problem vanished immediately, and I've tested it multiple times without any recurrence. This product really delivered!"