I have a 2001 Dodge truck with a 360 gasser and AT. It developed what turns out to be a typical problem with that transmission. At highway speeds and going up inclines it pulses (I should say pulsed, it is all better now) in and out of overdrive. That causes lots of problems in the long run. Turns out it is just a gunked up screen on the overdrive solenoid, or something like that. If you catch it early enough the can of seafoam cleans it right up. If you wait a little bit then it is $200 + labor for new overdrive solenoids. If you wait even longer it will cost you a transmission rebuild. I caught it early. $5 and the problem faded away over the next 1000 miles. It has been 10,000+ now and the problem has not reared it's ugly head again. A couple more thousand miles and I will be ready for my 60,000 miles transmission flush, filter, & fluid.

Seafoam transmission tune is a solid product. The injector cleaner works well also.

-Jim

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1995 S350D, Green with black leather interior.
Bought January 2008 w/ 233,xxx miles.
I did 22,000 miles during the first year of ownership.