My brothers gears in his rear end went out so we where talking to our mechanic about it among with the other list of things wrong with the truck lol and he brought up the symptom of a trans shutter when going about 45. I told him I have that problem and he gave me this 2 oz tube of Dr. Tranny and he said it should fix the problem. He says the shutter is the torque converter engaging and disengaging excessively. He has never steered me wrong so I decided to put it in, it just goes in where you add transmission fluid and it fixed my problem. I did about a 90-100 mile trip today (2 different trip, 1 about 90 and the other about 10) and my problem is absolutely gone.

So at the end of story time we always have questions lol, but my question is what does this stuff do? Obviously it fixed the shutter, but how?

 

It might work very well. - Might.

Basically Friction modifier...very much like. Yep, like the rear end stuff.

A sort of old trick that has worked many times in the past. So, -it's a valid fix, - if that's the problem and the correct amount is used.

 

Yup, friction modifier that helps the clutches in the tranny slip differently and stops/reduces shudder.
Yes it works, but it does not fix the problem, just masks it, but probably really will not make a difference in longevity.

 

It actually doesnt effect the transmission or longevity one bit. It just stops the torque converter clutch from slipping. Which is what causes the shudder you are feeling.

 

So since it stops the converter clutch from slipping, won't that elongate the life because it is now not slipping? Or is this basically making the shutter go away but it is still slipping?

 

Its wont prolong the life of the converter. There are still certain situations that the converter will slip. Especially under heavy load in 3rd gear. It will still slip. It just wont shudder.