Have a 91 Dodge B250 van. Local mechanic back-flushed transmission instead of replacing filter and fluid like I asked. Needless to say that is when I started having problems such as slipping and eratic shifts especially when in overdrive, could hardly pull a hill. He stated that this was a common problem with Dodge, he assumed because the odometer read 140+ miles that the torque convertor was the problem or the catalitic convertor and would not even look at the problem. He not knowing that we just two years before had the transmission professionally rebuilt all the way through with a new torque convertor. Being half- way mechinically minded I could not see how it was the cat/convertor or the torque convertor since we had no problems before we took in for oil/trans/filter and state inspection. So since he would not deal with the problem I changed the trans fluid and filter and still had a slipping problem, figuring he dislodged some trash somewhere and it was now stuck in a valve, so I decided I had nothing to lose and purchased your transmission repair. I added the entire contents in Advance Auto's parking lot, reading the part "Effects Felt Immediately", yeah right I thought, but like I said I had nothing to lose. Sure enough by the time I went around the corner out of the lot and pulled onto the highway the tranny shifted just as if it were brand new, being a heavy van it still would not spin the wheels but there was an immediate effect of good pulling ability and shifting points. Not to long, not to short, but sharp points, the down shifts were also greatly improved. The first hill I encountered only a 1/2 mile away would be where the real test would come in, usually the van would drop out of O.D. and really slip and the engine rev up while pulling this hill. Wow stayed in O.D. no drop in mph or or higher rpms. Pulled great. I still believe that this deal of back flushing should include the filter being changed, I can't see taking a chance of breaking loose particiles in tranny without changing a $12 filter & gasket. Next time I will change filter & fluid myself and add a bottle of your tranmission additive myself. Would not have believed it if I had not done it myself, I have always been against adding other fluids thinking if that they actually worked the oil companies would add them themselves, was I wrong. Thanks you may have saved me a lot of money even without anyone looking at tranny.