Hard shifting

Mrfin

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If your transmission shifts really hard and your overdrive light flashes everyone is calling it limp mode.
it’s in the instrument cluster
A sensor in your instrument cluster is not sending the correct voltage to the shift sensor in the rear end.
I ordered Another instrument cluster off eBay problem solved shifts smooth.
1993 F350
 

franklin2

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The rearend sends the signal to the cluster, not the other way around. The cluster takes the raw signal from the rearend and converts it to a speed signal which is then sent to the transmission computer, the ABS computer, and the cruise control box. They call the thing in the cluster a PSOM module that converts the sensor signal to the vehicle speed signal. Yours must have been bad. Glad you got it fixed.
 

BW42

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Well, been tracing a limp mode problem for a couple of years on my 93 F350, 7.3 idi, no turbo, E4OD tranny. This is the first time someone has suggested the PSOM module. Where exactly is it located on the instrument cluster?? Many years ago, the instrument cluster went crazy during a trip to Alabama. After returning to OK, replaced the speed sensor on the rear axle -- fixed that. Now it jumps to limp mode, mostly during damp weather. Most fixit books don't identify "minor" items like this -- don't want to take the whole truck apart to find this module -- BW
 

Reggie f250

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The psom is on the back of the speedometer. The cluster needs to be taken apart to access it. There is a lot of discussion about them. There are also utube videos about fixing them if you are up for soldering small parts.
 

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