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My experience as a young man driving old cars was that additives were almost always a waste of money. When a mechanic I trust told me a couple of years ago that this 2-oz tube contained the friction modifiers that distinguished Mercon V from previous formulations of transmission fluids, I thought it might be worth a try--particularly since a full flush and refill with Mercon V on my Ford product's 4R70W would cost about $180 where I live. (My trans fliud was still bright red, didn't smell burned, and didn't show particles in it.)Dr. Tranny's stopped the torque-converter lock-up shudder. Don't know for how long, but it's completely gone.If you own a Mercury Grand Marquis, Ford Crown Vic, F-150, Explorer, Mustang, Lincoln Town Car, or anything with Ford's 4R70W transmission, I'd certainly try it. Those are, on the whole, good vehicles, but that trans since 1998 is notorious for this shudder problem as early as 60,000 miles. About other vehicles, I have no...Read more

Buy it, it works for the shudder. My wifes 98 Explorer had a terrible shudder for about three months and I was dreading taking it in for repairs. When reading about transmission shudder all over the internet a lot of people suggested Dr. Trannys Instant Shudder Fixx, I ordered some and put it in and within ONE mile the shudder was COMPLETELY gone. WOOHOO! I hear that it has something to do with the torque converter not locking up completly but after adding this it shifts smoothly and no more washboard shudder! Try it, it's only about six bucks. Oh, yeah, just pour it in the transmission filler tube while running with the transmission in "PARK"Follow up review SIX YEARS LATER!!!Still working great, have not had shudder since, tranny is fine! Can't believe it!

I've been around mechanical contraptions all my life, worked as an equipment technician for a large state agency for 30 years and I've seen my share of "fixits in a tube", pretty much none of which that ever worked. I have a Chevy Avalanche (1500, 4L60E trans.), I love this truck and I baby the thing...in spite of the fact that it puked the transmission at 36,000 miles. The dealer rebuilt it, 30,000 miles later I had a synthetic flush performed, figured I was doing everything right. A few months ago, around 90,000 miles, it developed that dreaded torque converter shudder! Right at highway speed under light cruise the truck would kick and buck steadily and the TCC would disengage at the slightest incline...which is the only time at least that it wouldn't buck. It was terrible. I did an internet search and kept seeing all these discussions on "Dr. Tranny's Instant Shudder Fixx". At six bucks (and I found it at the local parts place) I figured there sure wasn't much to lose. I dumped it...Read more