BlueDevil Transmission Sealer – 16 oz | Seals Leaks in Automatic & Manual Transmissions | Restores Seals & Prevents Fluid Loss

Good quality and price

Transmission started leaking about 2 weeks ago. Wife called me and said there is oil on the garage floor after Ieft. Cleaned it up. The next morning there was oil on the floor again. After investigating I realized it was transmission fluid. Went to Amazon to see if there was anything available to stop the leak. There was several options, seemed like the Blue Devil had the best reviews so I ordered. Took a few days to get it. By the time I got it car was leaking a lot. My car holds 12 quarts of fluid so per recommendation I put 12 oz of Blue Devil in. I then topped of the transmission with 5 quarts of Transmission fluid. So in 2 weeks I had lost about 6 quarts of fluid, so quite the leak. Had my doubts but after driving several hundred miles it looks like the leak has completely stopped. Now if it holds up I will be amazed.

While it's been less than a week since added to leaky 30 yo trans, no sign of leakage yet.

Good price

Well shortly after adding this product my transmission started acting up. Mostly the reverse would shake the entire vehicle and not get into gear. Just got a call from the shop and his first question - did you use an additive? I say yes and he says that the additive swelled all the rubber in the transmission to more than double their original size, causing the issues. Total $4000 to fix what this $13 bottle of pure junk did. Reaching out to the company to ask if they have any guarantees....not expecting much. Do NOT use this product, you've been warned...

This looked like it worked for some folks guess it depends on the situation. Didn't make a bit of difference for me though.

My 1986 Suburban had a bad drip from the transmission, I'd lose about a quart every 200 miles. It was likely the front seal which a shop quoted me over $1000 to replace so figured I'd give this stuff a try and it actually worked! Put a piece of cardboard under my truck and after two weeks there's only three drops when befo addedre the cardboard would've had a large spot. I warmed my truck up, shut it off, added the whole bottle and drove 100 miles to go camping. The next day, drove 100 miles home and the leak has slowed to almost nothing!

I had a very long post and now lost it all. So this post is the condensed version!I have 1995 GMC Jimmy with 240,000 miles, it had a terrible transfer case input seal leak, leaking transmission fluid into the transfer case. Leaking about quart of transmission fluid into transfer case every 120 miles.. This happened after the Jimmy sat a year and was not drove. Leak was so bad that transfer case would get over filled and then transmission fluid would leak out the vent that is attached to the transmission fill and dipstick tube..Well it cost 350$ to get it fixed so I wanted to try transmission fluid sealers.1.) I first tried Lucas brand Transmission fix/sealer, it did not fix the leak. (it is good stuff though, all of their products)2.) Then I tried a petroleum based Transmission sealer I bought from Walmart, can't remember brand for about $6. It did not stop the leak.3.) Then I did a large amount of research online and found a general leak sealer that by it 300 reviews on amazon.com sounded awesome. It was ATP AT-205 Re-Seal Stops Leaks, 8 Ounce Bottle for about $11. It did not stop the leak. (may be good stuff for other applications, but didn't work)4.) THEN WITH MORE RESEARCH I FOUND: Blue Devil Transmission Sealer for about $12.50, and seen great reviews for it. I put the Blue Devil Transmission Sealer in and drove to work two days in a row at about 230 miles total AND IT SEALED MY VERY BAD LEAKING TRANSFER CASE INPUT SEAL!!! It hasn't leaked since and I have checked it everyday I have drove now for about 2 weeks.