What could cause my standard transmission to gear down on it's own? on 1994 Dodge Ram 2500

When driving on the highway, the transmission will jump from 5th to 4th on it's own.

by in Point Roberts, WA on April 08, 2009
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3 answers 1 comment
ANSWER by , April 08, 2009
Do you have an overdrive switch for this transmission? Is it possible it is shifting out of overdrive?
COMMENT by , June 22, 2010
Sounds like a synchro gear is bad.
ANSWER by , September 11, 2010
check brake light switch on fuel petal it down shift when you hit brakes
ANSWER by , July 26, 2010
had same problem and sometimes it took very high rpm s to get it to shift up. took it to a transmission shop they replaced 2 sensors in the transmission. $300 bucks. 2000 miles later it started doing it again..it ended up being the computer (ecm) and i never had that problem again.